PRODUCTION OF OLIGOSACCHARIDE MIXTURES BY A CELL

Abstract

This disclosure is in the technical field of synthetic biology and metabolic engineering. More particularly, this disclosure is in the technical field of cultivation or fermentation of metabolically engineered cells. This disclosure provides a method for the production of a mixture of at least two different oligosaccharides by a cell as well as the purification of at least one of the oligosaccharides from the cultivation. In addition, this disclosure provides a method for the production of a mixture of at least two different oligosaccharides by a metabolically engineered cell as well as the purification of at least one of the oligosaccharides from the cultivation.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase entry under 35 U.S.C. § 371 of International Patent Application PCT/EP2021/072268, filed Aug. 10, 2021, designating the United States of America and published as International Patent Publication WO 2022/034074 A1 on Feb. 17, 2022, which claims the benefit under Article 8 of the Patent Cooperation Treaty to European Patent Application Serial No. 20190198.0, filed Aug. 10, 2020, to European Patent Application Serial No. 20190200.4, filed Aug. 10, 2020, to European Patent Application Serial No. 20190201.2, filed Aug. 10, 2020, to European Patent Application Serial No. 20190202.0, filed Aug. 10, 2020, to European Patent Application Serial No. 20190203.8, filed Aug. 10, 2020, to European Patent Application Serial No. 20190204.6, filed Aug. 10, 2020, to European Patent Application Serial No. 20190205.3, filed Aug. 10, 2020, to European Patent Application Serial No. 20190206.1, filed Aug. 10, 2020, to European Patent Application Serial No. 20190207.9, filed Aug. 10, 2020, to European Patent Application Serial No. 20190208.7, filed Aug. 10, 2020, to European Patent Application Serial No. 21168997.1, filed Apr. 16, 2021, to European Patent Application Serial No. 21186202.4, filed Jul. 16, 2021, and to European Patent Application Serial No. 21186203.2, filed Jul. 16, 2021.

TECHNICAL FIELD

This disclosure is in the technical field of synthetic biology and metabolic engineering. More particularly, this disclosure is in the technical field of cultivation or fermentation of metabolically engineered cells. This disclosure provides a method for the production of a mixture of at least two different oligosaccharides by a cell as well as the purification of at least one of the oligosaccharides from the cultivation. In addition, this disclosure provides a method for the production of a mixture of at least two different oligosaccharides by a metabolically engineered cell as well as the purification of at least one of the oligosaccharides from the cultivation.

BACKGROUND

Oligosaccharides, often present as glyco-conjugated forms to proteins and lipids, are involved in many vital phenomena such as differentiation, development and biological recognition processes related to the development and progress of fertilization, embryogenesis, inflammation, metastasis and host pathogen adhesion. Oligosaccharides can also be present as unconjugated glycans in body fluids and human milk wherein they also modulate important developmental and immunological processes (Bode, Early Hum. Dev. 1-4 (2015); Reily et al., Nat. Rev. Nephrol. 15, 346-366 (2019); Varki, Glycobiology 27, 3-49 (2017)). There is large scientific and commercial interest in oligosaccharide mixtures due to the wide functional spectrum of oligosaccharides. Yet, the availability of oligosaccharide mixtures is limited as production relies on chemical or chemo-enzymatic synthesis or on purification from natural sources such as e.g., animal milk. Chemical synthesis methods are laborious and time-consuming and because of the large number of steps involved they are difficult to scale-up. Enzymatic approaches using glycosyltransferases offer many advantages above chemical synthesis. Glycosyltransferases catalyze the transfer of a sugar moiety from an activated nucleotide-sugar donor onto saccharide or non-saccharide acceptors (Coutinho et al., J. Mol. Biol. 328 (2003) 307-317). These glycosyltransferases are the source for biotechnologists to synthesize oligosaccharides and are used both in (chemo)enzymatic approaches as well as in cell-based production systems. However, stereospecificity and regioselectivity of glycosyltransferases are still a formidable challenge. In addition, chemo-enzymatic approaches need to regenerate in situ nucleotide-sugar donors. Cellular production of oligosaccharides needs tight control of spatiotemporal availability of adequate levels of nucleotide-sugar donors in proximity of complementary glycosyltransferases. Due to these difficulties, current methods often result in the synthesis of a single oligosaccharide instead of an oligosaccharide mixture.

BRIEF SUMMARY

Provided are tools and methods by means of which an oligosaccharide mixture comprising at least two different oligosaccharides can be produced by a cell, preferably a single cell, in an efficient, time and cost-effective way and if needed, continuous process.

Provided are a cell and a method for the production of an oligosaccharide mixture comprising at least two different oligosaccharides wherein the cell is metabolically engineered for the production of the oligosaccharides.

Surprisingly, it has now been found that it is possible to produce oligosaccharide mixtures comprising at least two different oligosaccharides by a single cell. This disclosure provides a method for the production of an oligosaccharide mixture comprising at least two different oligosaccharides. The method comprises the steps of providing a cell that expresses at least one glycosyltransferase and is capable to synthesize a nucleotide-sugar that is donor for the glycosyltransferase, wherein the cell is cultivated with at least two acceptors for the oligosaccharide production, wherein any one of the acceptors is a di- or oligosaccharide. This disclosure also provides methods to separate at least one of the produced oligosaccharides from the oligosaccharide mixture. Furthermore, this disclosure provides a cell metabolically engineered for production of an oligosaccharide mixture comprising at least two different oligosaccharides.

Definitions

The words used in this specification to describe this disclosure and its various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification structure, material or acts beyond the scope of the commonly defined meanings. Thus, if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself.

The various embodiments and aspects of embodiments of this disclosure disclosed herein are to be understood not only in the order and context specifically described in this specification, but to include any order and any combination thereof. Whenever the context requires, all words used in the singular number shall be deemed to include the plural and vice versa. Unless defined otherwise, all technical and scientific terms used herein generally have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein and the laboratory procedures in cell culture, molecular genetics, organic chemistry and nucleic acid chemistry and hybridization described herein are those well-known and commonly employed in the art. Standard techniques are used for nucleic acid and peptide synthesis. Generally, purification steps are performed according to the manufacturer's specifications.

In the specification, there have been disclosed embodiments of this disclosure, and although specific terms are employed, the terms are used in a descriptive sense only and not for purposes of limitation, the scope of this disclosure being set forth in the following claims. It must be understood that the illustrated embodiments have been set forth only for the purposes of example and that it should not be taken as limiting this disclosure. It will be apparent to those skilled in the art that alterations, other embodiments, improvements, details and uses can be made consistent with the letter and spirit of this disclosure herein and within the scope of this invention, which is limited only by the claims, construed in accordance with the patent law, including the doctrine of equivalents. In the claims that follow, reference characters used to designate claim steps are provided for convenience of description only, and are not intended to imply any particular order for performing the steps.

In this document and in its claims, the verb “to comprise” and its conjugations is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. In addition the verb “to consist” may be replaced by “to consist essentially of” meaning that a composition as defined herein may comprise additional component(s) than the ones specifically identified, the additional component(s) not altering the unique characteristic of this disclosure. In addition, reference to an element by the indefinite article “a” or “an” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. The indefinite article “a” or “an” thus usually means “at least one.” Throughout this disclosure, unless explicitly stated otherwise, the articles “a” and “an” are preferably replaced by “at least two,” more preferably by “at least three,” even more preferably by “at least four,” even more preferably by “at least five,” even more preferably by “at least six,” most preferably by “at least two.”

Each embodiment as identified herein may be combined together unless otherwise indicated. All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. The full content of the priority applications, including EP20190198, EP20190200, EP20190204 and EP20190205, are also incorporated by reference to the same extent as if the priority applications were specifically and individually indicated to be incorporated by reference.

According to this disclosure, the term “polynucleotide(s)” generally refers to any polyribonucleotide or polydeoxyribonucleotide, which may be unmodified RNA or DNA or modified RNA or DNA. “Polynucleotide(s)” include, without limitation, single- and double-stranded DNA, DNA that is a mixture of single- and double-stranded regions or single-, double- and triple-stranded regions, single- and double-stranded RNA, and RNA that is mixture of single- and double-stranded regions, hybrid molecules comprising DNA and RNA that may be single-stranded or, more typically, double-stranded, or triple-stranded regions, or a mixture of single- and double-stranded regions. In addition, “polynucleotide” as used herein refers to triple-stranded regions comprising RNA or DNA or both RNA and DNA. The strands in such regions may be from the same molecule or from different molecules. The regions may include all of one or more of the molecules, but more typically involve only a region of some of the molecules. One of the molecules of a triple-helical region often is an oligonucleotide. As used herein, the term “polynucleotide(s)” also includes DNAs or RNAs as described above that contain one or more modified bases. Thus, DNAs or RNAs with backbones modified for stability or for other reasons are “polynucleotide(s)” according to this disclosure. Moreover, DNAs or RNAs comprising unusual bases, such as inosine, or modified bases, such as tritylated bases, are to be understood to be covered by the term “polynucleotides.” It will be appreciated that a great variety of modifications have been made to DNA and RNA that serve many useful purposes known to those of skill in the art. The term “polynucleotide(s)” as it is employed herein embraces such chemically, enzymatically or metabolically modified forms of polynucleotides, as well as the chemical forms of DNA and RNA characteristic of viruses and cells, including, for example, simple and complex cells. The term “polynucleotide(s)” also embraces short polynucleotides often referred to as oligonucleotide(s).

“Polypeptide(s)” refers to any peptide or protein comprising two or more amino acids joined to each other by peptide bonds or modified peptide bonds. “Polypeptide(s)” refers to both short chains, commonly referred to as peptides, oligopeptides and oligomers and to longer chains generally referred to as proteins. Polypeptides may contain amino acids other than the 20 gene encoded amino acids. “Polypeptide(s)” include those modified either by natural processes, such as processing and other post-translational modifications, but also by chemical modification techniques. Such modifications are well described in basic texts and in more detailed monographs, as well as in a voluminous research literature, and they are well known to the skilled person. The same type of modification may be present in the same or varying degree at several sites in a given polypeptide. Furthermore, a given polypeptide may contain many types of modifications. Modifications can occur anywhere in a polypeptide, including the peptide backbone, the amino acid sidechains, and the amino or carboxyl termini. Modifications include, for example, acetylation, acylation, ADP-ribosylation, amidation, covalent attachment of flavin, covalent attachment of a heme moiety, covalent attachment of a nucleotide or nucleotide derivative, covalent attachment of a lipid or lipid derivative, covalent attachment of phosphotidylinositol, cross-linking, cyclization, disulfide bond formation, demethylation, formation of covalent cross-links, formation of pyroglutamate, formylation, gamma-carboxylation, glycosylation, GPI anchor formation, hydroxylation, iodination, methylation, myristoylation, oxidation, proteolytic processing, phosphorylation, prenylation, racemization, lipid attachment, sulfation, gamma-carboxylation of glutamic acid residues, hydroxylation and ADP-ribosylation, selenoylation, transfer-RNA mediated addition of amino acids to proteins, such as arginylation, and ubiquitination. Polypeptides may be branched or cyclic, with or without branching. Cyclic, branched and branched circular polypeptides may result from post-translational natural processes and may be made by entirely synthetic methods, as well.

The term “polynucleotide encoding a polypeptide” as used herein encompasses polynucleotides that include a sequence encoding a polypeptide of this disclosure. The term also encompasses polynucleotides that include a single continuous region or discontinuous regions encoding the polypeptide (for example, interrupted by integrated phage or an insertion sequence or editing) together with additional regions that also may contain coding and/or non-coding sequences.

“Isolated” means altered “by the hand of man” from its natural state, i.e., if it occurs in nature, it has been changed or removed from its original environment, or both. For example, a polynucleotide or a polypeptide naturally present in a living organism is not “isolated,” but the same polynucleotide or polypeptide separated from the coexisting materials of its natural state is “isolated,” as the term is employed herein. Similarly, a “synthetic” sequence, as the term is used herein, means any sequence that has been generated synthetically and not directly isolated from a natural source. “Synthesized,” as the term is used herein, means any synthetically generated sequence and not directly isolated from a natural source.

The terms “recombinant” or “transgenic” or “metabolically engineered” or “genetically modified,” as used herein with reference to a cell or host cell are used interchangeably and indicates that the cell replicates a heterologous nucleic acid, or expresses a peptide or protein encoded by a heterologous nucleic acid (i.e., a sequence “foreign to the cell” or a sequence “foreign to the location or environment in the cell”). Such cells are described to be transformed with at least one heterologous or exogenous gene, or are described to be transformed by the introduction of at least one heterologous or exogenous gene. Metabolically engineered or recombinant or transgenic cells can contain genes that are not found within the native (non-recombinant) form of the cell. Recombinant cells can also contain genes found in the native form of the cell wherein the genes are modified and re-introduced into the cell by artificial means. The terms also encompass cells that contain a nucleic acid endogenous to the cell that has been modified or its expression or activity has been modified without removing the nucleic acid from the cell; such modifications include those obtained by gene replacement, replacement of a promoter; site-specific mutation; and related techniques. Accordingly, a “recombinant polypeptide” is one which has been produced by a recombinant cell. A “heterologous sequence” or a “heterologous nucleic acid,” as used herein, is one that originates from a source foreign to the particular cell (e.g., from a different species), or, if from the same source, is modified from its original form or place in the genome. Thus, a heterologous nucleic acid operably linked to a promoter is from a source different from that from which the promoter was derived, or, if from the same source, is modified from its original form or place in the genome. The heterologous sequence may be stably introduced, e.g., by transfection, transformation, conjugation or transduction, into the genome of the host microorganism cell, wherein techniques may be applied that will depend on the cell and the sequence that is to be introduced. Various techniques are known to a person skilled in the art and are, e.g., disclosed in Sambrook et al., Molecular Cloning: A Laboratory Manual, 2nd Ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y. (1989). The term “mutant” cell or microorganism as used within the context of this disclosure refers to a cell or microorganism that is genetically modified.

The term “endogenous,” within the context of this disclosure refers to any polynucleotide, polypeptide or protein sequence that is a natural part of a cell and is occurring at its natural location in the cell chromosome and of which the control of expression has not been altered compared to the natural control mechanism acting on its expression. The term “exogenous” refers to any polynucleotide, polypeptide or protein sequence that originates from outside the cell under study and not a natural part of the cell or that is not occurring at its natural location in the cell chromosome or plasmid.

The term “heterologous” when used in reference to a polynucleotide, gene, nucleic acid, polypeptide, or enzyme refers to a polynucleotide, gene, nucleic acid, polypeptide, or enzyme that is from a source or derived from a source other than the host organism species. In contrast a “homologous” polynucleotide, gene, nucleic acid, polypeptide, or enzyme is used herein to denote a polynucleotide, gene, nucleic acid, polypeptide, or enzyme that is derived from the host organism species. When referring to a gene regulatory sequence or to an auxiliary nucleic acid sequence used for maintaining or manipulating a gene sequence (e.g., a promoter, a 5′ untranslated region, 3′ untranslated region, poly A addition sequence, intron sequence, splice site, ribosome binding site, internal ribosome entry sequence, genome homology region, recombination site, etc.), “heterologous” means that the regulatory sequence or auxiliary sequence is not naturally associated with the gene with which the regulatory or auxiliary nucleic acid sequence is juxtaposed in a construct, genome, chromosome, or episome. Thus, a promoter operably linked to a gene to which it is not operably linked to in its natural state (i.e., in the genome of a non-genetically engineered organism) is referred to herein as a “heterologous promoter,” even though the promoter may be derived from the same species (or, in some cases, the same organism) as the gene to which it is linked.

The term “modified activity” of a protein or an enzyme relates to a change in activity of the protein or the enzyme compared to the wild type, i.e., natural, activity of the protein or enzyme. The modified activity can either be an abolished, impaired, reduced or delayed activity of the protein or enzyme compared to the wild type activity of the protein or the enzyme but can also be an accelerated or an enhanced activity of the protein or the enzyme compared to the wild type activity of the protein or the enzyme. A modified activity of a protein or an enzyme is obtained by modified expression of the protein or enzyme or is obtained by expression of a modified, i.e., mutant form of the protein or enzyme. A modified activity of an enzyme further relates to a modification in the apparent Michaelis constant Km and/or the apparent maximal velocity (Vmax) of the enzyme.

The term “modified expression” of a gene relates to a change in expression compared to the wild type expression of the gene in any phase of the production process of the encoded protein. The modified expression is either a lower or higher expression compared to the wild type, wherein the term “higher expression” is also defined as “overexpression” of the gene in the case of an endogenous gene or “expression” in the case of a heterologous gene that is not present in the wild type strain. Lower expression or reduced expression is obtained by means of common well-known technologies for a skilled person (such as the usage of siRNA, CRISPR, CRISPRi, riboswitches, recombineering, homologous recombination, ssDNA mutagenesis, RNAi, miRNA, asRNA, mutating genes, knocking-out genes, transposon mutagenesis, . . . ) that are used to change the genes in such a way that they are less-able (i.e., statistically significantly ‘less-able’ compared to a functional wild-type gene) or completely unable (such as knocked-out genes) to produce functional final products. The term “riboswitch” as used herein is defined to be part of the messenger RNA that folds into intricate structures that block expression by interfering with translation. Binding of an effector molecule induces conformational change(s) permitting regulated expression post-transcriptionally. Next to changing the gene of interest in such a way that lower expression is obtained as described above, lower expression can also be obtained by changing the transcription unit, the promoter, an untranslated region, the ribosome binding site, the Shine Dalgarno sequence or the transcription terminator. Lower expression or reduced expression can be obtained, for instance, by mutating one or more base pairs in the promoter sequence or changing the promoter sequence fully to a constitutive promoter with a lower expression strength compared to the wild type or an inducible promoter that result in regulated expression or a repressible promoter that results in regulated expression Overexpression or expression is obtained by means of common well-known technologies for a skilled person (such as the usage of artificial transcription factors, de novo design of a promoter sequence, ribosome engineering, introduction or re-introduction of an expression module at euchromatin, usage of high-copy-number plasmids), wherein the gene is part of an “expression cassette” that relates to any sequence in which a promoter sequence, untranslated region sequence (containing either a ribosome binding sequence, Shine Dalgarno or Kozak sequence), a coding sequence and optionally a transcription terminator is present, and leading to the expression of a functional active protein. The expression is either constitutive or regulated.

The term “constitutive expression” is defined as expression that is not regulated by transcription factors other than the subunits of RNA polymerase (e.g., the bacterial sigma factors like σ⁷⁰, σ⁵⁴, or related σ-factors and the yeast mitochondrial RNA polymerase specificity factor MTF1 that co-associate with the RNA polymerase core enzyme) under certain growth conditions. Non-limiting examples of such transcription factors are CRP, Lad, ArcA, Cra, IclR in E. coli or, Aft2p, Crzlp, Skn7 in Saccharomyces cerevisiae, or, DeoR, GntR, Fur in B. subtilis. These transcription factors bind on a specific sequence and may block or enhance expression in certain growth conditions. The RNA polymerase is the catalytic machinery for the synthesis of RNA from a DNA template. RNA polymerase binds a specific sequence to initiate transcription, for instance, via a sigma factor in prokaryotic hosts or via MTF1 in yeasts. Constitutive expression offers a constant level of expression with no need for induction or repression.

The term “regulated expression” is defined as expression that is regulated by transcription factors other than the subunits of RNA polymerase (e.g., bacterial sigma factors) under certain growth conditions. Examples of such transcription factors are described above. Commonly expression regulation is obtained by means of an inducer or repressor, such as but not limited to IPTG, arabinose, rhamnose, fucose, allo-lactose or pH shifts, or temperature shifts or carbon depletion or acceptors or the produced product or chemical repression.

The term “expression by a natural inducer” is defined as a facultative or regulatory expression of a gene that is only expressed upon a certain natural condition of the host (e.g., organism being in labor, or during lactation), as a response to an environmental change (e.g., including but not limited to hormone, heat, cold, pH shifts, light, oxidative or osmotic stress/signaling), or dependent on the position of the developmental stage or the cell cycle of the host cell including but not limited to apoptosis and autophagy.

The term “inducible expression upon chemical treatment” is defined as a facultative or regulatory expression of a gene that is only expressed upon treatment with a chemical inducer or repressor, wherein the inducer and repressor comprise but are not limited to an alcohol (e.g., ethanol, methanol), a carbohydrate (e.g., glucose, galactose, glycerol, lactose, arabinose, rhamnose, fucose, allo-lactose), metal ions (e.g., aluminum, copper, zinc), nitrogen, phosphates, IPTG, acetate, formate, xylene. The term “control sequences” refers to sequences recognized by the cells transcriptional and translational systems, allowing transcription and translation of a polynucleotide sequence to a polypeptide. Such DNA sequences are thus necessary for the expression of an operably linked coding sequence in a particular cell or organism. Such control sequences can be, but are not limited to, promoter sequences, ribosome binding sequences, Shine Dalgarno sequences, Kozak sequences, transcription terminator sequences. The control sequences that are suitable for prokaryotes, for example, include a promoter, optionally an operator sequence, and a ribosome binding site. Eukaryotic cells are known to utilize promoters, polyadenylation signals, and enhancers. DNA for a presequence or secretory leader may be operably linked to DNA for a polypeptide if it is expressed as a preprotein that participates in the secretion of the polypeptide; a promoter or enhancer is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it affects the transcription of the sequence; or a ribosome binding site is operably linked to a coding sequence if it is positioned so as to facilitate translation. The control sequences can furthermore be controlled with external chemicals, such as, but not limited to, IPTG, arabinose, lactose, allo-lactose, rhamnose or fucose via an inducible promoter or via a genetic circuit that either induces or represses the transcription or translation of the polynucleotide to a polypeptide.

Generally, “operably linked” means that the DNA sequences being linked are contiguous, and, in the case of a secretory leader, contiguous and in reading phase. However, enhancers do not have to be contiguous.

The term “modified expression of a protein” as used herein refers to i) higher expression or overexpression of an endogenous protein, ii) expression of a heterologous protein or iii) expression and/or overexpression of a variant protein that has a higher activity compared to the wild-type (i.e., native) protein.

As used herein, the term “mammary cell(s)” generally refers to mammary epithelial cell(s), mammary-epithelial luminal cell(s), or mammalian epithelial alveolar cell(s), or any combination thereof. As used herein, the term “mammary-like cell(s)” generally refers to cell(s) having a phenotype/genotype similar (or substantially similar) to natural mammary cell(s) but is/are derived from non-mammary cell source(s). Such mammary-like cell(s) may be engineered to remove at least one undesired genetic component and/or to include at least one predetermined genetic construct that is typical of a mammary cell. Non-limiting examples of mammary-like cell(s) may include mammary epithelial-like cell(s), mammary epithelial luminal-like cell(s), non-mammary cell(s) that exhibits one or more characteristics of a cell of a mammary cell lineage, or any combination thereof. Further non-limiting examples of mammary-like cell(s) may include cell(s) having a phenotype similar (or substantially similar) to natural mammary cell(s), or more particularly a phenotype similar (or substantially similar) to natural mammary epithelial cell(s). A cell with a phenotype or that exhibits at least one characteristic similar to (or substantially similar to) a natural mammary cell or a mammary epithelial cell may comprise a cell (e.g., derived from a mammary cell lineage or a non-mammary cell lineage) that exhibits either naturally, or has been engineered to, be capable of expressing at least one milk component.

As used herein, the term “non-mammary cell(s)” may generally include any cell of non-mammary lineage. In the context of this disclosure, a non-mammary cell can be any mammalian cell capable of being engineered to express at least one milk component. Non-limiting examples of such non-mammary cell(s) include hepatocyte(s), blood cell(s), kidney cell(s), cord blood cell(s), epithelial cell(s), epidermal cell(s), myocyte(s), fibroblast(s), mesenchymal cell(s), or any combination thereof. In some instances, molecular biology and genome editing techniques can be engineered to eliminate, silence, or attenuate myriad genes simultaneously.

Throughout this disclosure, unless explicitly stated otherwise, the expressions “capable of . . . <verb>” and “capable to . . . <verb>” are preferably replaced with the active voice of the verb and vice versa. For example, the expression “capable of expressing” is preferably replaced with “expresses” and vice versa, i.e., “expresses” is preferably replaced with “capable of expressing.”

“Variant(s)” as the term is used herein, is a polynucleotide or polypeptide that differs from a reference polynucleotide or polypeptide, respectively, but retains essential properties. A typical variant of a polynucleotide differs in nucleotide sequence from another, reference polynucleotide. Changes in the nucleotide sequence of the variant may or may not alter the amino acid sequence of a polypeptide encoded by the reference polynucleotide. Nucleotide changes may result in amino acid substitutions, additions, deletions, fusions and truncations in the polypeptide encoded by the reference sequence, as discussed below. A typical variant of a polypeptide differs in amino acid sequence from another, reference polypeptide. Generally, differences are limited so that the sequences of the reference polypeptide and the variant are closely similar overall and, in many regions, identical. A variant and reference polypeptide may differ in amino acid sequence by one or more substitutions, additions, deletions in any combination. A substituted or inserted amino acid residue may or may not be one encoded by the genetic code. A variant of a polynucleotide or polypeptide may be a naturally occurring such as an allelic variant, or it may be a variant that is not known to occur naturally. Non-naturally occurring variants of polynucleotides and polypeptides may be made by mutagenesis techniques, by direct synthesis, and by other recombinant methods known to the persons skilled in the art.

The term “functional homolog” as used herein describes those molecules that have sequence similarity (in other words, homology) and also share at least one functional characteristic such as a biochemical activity (Altenhoff et al., PLoS Comput. Biol. 8 (2012) e1002514). Functional homologs will typically give rise to the same characteristics to a similar, but not necessarily the same, degree. Functionally homologous proteins give the same characteristics where the quantitative measurement produced by one homolog is at least 10 percent of the other; more typically, at least 20 percent, between about 30 percent and about 40 percent; for example, between about 50 percent and about 60 percent; between about 70 percent and about 80 percent; or between about 90 percent and about 95 percent; between about 98 percent and about 100 percent, or greater than 100 percent of that produced by the original molecule. Thus, where the molecule has enzymatic activity the functional homolog will have the above-recited percent enzymatic activities compared to the original enzyme. Where the molecule is a DNA-binding molecule (e.g., a polypeptide) the homolog will have the above-recited percentage of binding affinity as measured by weight of bound molecule compared to the original molecule.

A functional homolog and the reference polypeptide may be naturally occurring polypeptides, and the sequence similarity may be due to convergent or divergent evolutionary events. Functional homologs are sometimes referred to as orthologs, where “ortholog,” refers to a homologous gene or protein that is the functional equivalent of the referenced gene or protein in another species.

Orthologous genes are homologous genes in different species that originate by vertical descent from a single gene of the last common ancestor, wherein the gene and its main function are conserved. A homologous gene is a gene inherited in two species by a common ancestor.

The term “ortholog” when used in reference to an amino acid or nucleotide/nucleic acid sequence from a given species refers to the same amino acid or nucleotide/nucleic acid sequence from a different species. It should be understood that two sequences are orthologs of each other when they are derived from a common ancestor sequence via linear descent and/or are otherwise closely related in terms of both their sequence and their biological function. Orthologs will usually have a high degree of sequence identity but may not (and often will not) share 100% sequence identity.

Paralogous genes are homologous genes that originate by a gene duplication event. Paralogous genes often belong to the same species, but this is not necessary. Paralogs can be split into in-paralogs (paralogous pairs that arose after a speciation event) and out-paralogs (paralogous pairs that arose before a speciation event). Between species out-paralogs are pairs of paralogs that exist between two organisms due to duplication before speciation. Within species out-paralogs are pairs of paralogs that exist in the same organism, but whose duplication event happened after speciation. Paralogs typically have the same or similar function.

Functional homologs can be identified by analysis of nucleotide and polypeptide sequence alignments. For example, performing a query on a database of nucleotide or polypeptide sequences can identify homologs of the polypeptide of interest like e.g., a biomass-modulating polypeptide, a glycosyltransferase, a protein involved in nucleotide-activated sugar synthesis or a membrane transporter protein. Sequence analysis can involve BLAST, Reciprocal BLAST, or PSI-BLAST analysis of non-redundant databases using amino acid sequence of a biomass-modulating polypeptide, a glycosyltransferase, a protein involved in nucleotide-activated sugar synthesis or a membrane transporter protein, respectively, as the reference sequence. Amino acid sequence is, in some instances, deduced from the nucleotide sequence. Typically, those polypeptides in the database that have greater than 40 percent sequence identity are candidates for further evaluation for suitability as a biomass-modulating polypeptide, a glycosyltransferase, a protein involved in nucleotide-activated sugar synthesis or a membrane transporter protein, respectively. Amino acid sequence similarity allows for conservative amino acid substitutions, such as substitution of one hydrophobic residue for another or substitution of one polar residue for another or substitution of one acidic amino acid for another or substitution of one basic amino acid for another etc. Preferably, by conservative substitutions is intended combinations such as glycine by alanine and vice versa; valine, isoleucine and leucine by methionine and vice versa; aspartate by glutamate and vice versa; asparagine by glutamine and vice versa; serine by threonine and vice versa; lysine by arginine and vice versa; cysteine by methionine and vice versa; and phenylalanine and tyrosine by tryptophan and vice versa. If desired, manual inspection of such candidates can be carried out in order to narrow the number of candidates to be further evaluated. Manual inspection can be performed by selecting those candidates that appear to have domains present in productivity-modulating polypeptides, e.g., conserved functional domains. The term “glycosyltransferase” as used herein refers to an enzyme capable to catalyze the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds. The as such synthesized oligosaccharides can be of the linear type or of the branched type and can contain multiple monosaccharide building blocks. A classification of glycosyltransferases using nucleotide diphospho-sugar, nucleotide monophospho-sugar and sugar phosphates and related proteins into distinct sequence-based families has been described (Campbell et al., Biochem. J. 326, 929-939 (1997)) and is available on the CAZy (CArbohydrate-Active EnZymes) website (www.cazy.org).

As used herein the glycosyltransferase can be selected from the list comprising but not limited to: fucosyltransferases (e.g., alpha-1,2-fucosyltransferases, alpha-1,3/1,4-fucosyltransferases, alpha-1,6-fucosyltransferases), sialyltransferases (e.g., alpha-2,3-sialyltransferases, alpha-2,6-sialyltransferases, alpha-2,8-sialyltransferases), galactosyltransferases (e.g., beta-1,3-galactosyltransferases, beta-1,4-galactosyltransferases, alpha-1,3-galactosyltransferases, alpha-1,4-galactosyltransferases), N-acetylglucosaminyltransferases, N-acetylgalactosaminyltransferases, glucosyltransferases, mannosyltransferases, N-acetylmannosaminyltransferases, xylosyltransferases, glucuronyltransferases, galacturonyl transferases, glucosaminyltransferases, N-glycolylneuraminyltransferases, rhamnosyltransferases, N-acetylrhamnosyltransferases, UDP-4-amino-4,6-dideoxy-N-acetyl-beta-L-altrosamine transaminases, UDP-N-acetylglucosamine enolpyruvyl transferases and fucosaminyltransferases.

Fucosyltransferases are glycosyltransferases that transfer a fucose residue (Fuc) from a GDP-fucose (GDP-Fuc) donor onto a glycan acceptor. Fucosyltransferases comprise alpha-1,2-fucosyltransferases, alpha-1,3-fucosyltransferases, alpha-1,4-fucosyltransferases and alpha-1,6-fucosyltransferases that catalyze the transfer of a Fuc residue from GDP-Fuc onto a glycan acceptor via alpha-glycosidic bonds. Fucosyltransferases can be found but are not limited to the GT10, GT11, GT23, GT65 and GT68 CAZy families. Sialyltransferases are glycosyltransferases that transfer a sialyl group (like Neu5Ac or Neu5Gc) from a donor (like CMP-Neu5Ac or CMP-Neu5Gc) onto a glycan acceptor. Sialyltransferases comprise alpha-2,3-sialyltransferases, alpha-2,6-sialyltransferases and alpha-2,8-sialyltransferases that catalyze the transfer of a sialyl group onto a glycan acceptor via alpha-glycosidic bonds. Sialyltransferases can be found but are not limited to the GT29, GT42, GT80 and GT97 CAZy families. Galactosyltransferases are glycosyltransferases that transfer a galactosyl group (Gal) from an UDP-galactose (UDP-Gal) donor onto a glycan acceptor. Galactosyltransferases comprise beta-1,3-galactosyltransferases, beta-1,4-galactosyltransferases, alpha-1,3-galactosyltransferases and alpha-1,4-galactosyltransferases that transfer a Gal residue from UDP-Gal onto a glycan acceptor via alpha- or beta-glycosidic bonds. Galactosyltransferases can be found but are not limited to the GT2, GT6, GT8, GT25 and GT92 CAZy families. Glucosyltransferases are glycosyltransferases that transfer a glucosyl group (Glc) from an UDP-glucose (UDP-Glc) donor onto a glycan acceptor. Glucosyltransferases comprise alpha-glucosyltransferases, beta-1,2-glucosyltransferases, beta-1,3-glucosyltransferases and beta-1,4-glucosyltransferases that transfer a Glc residue from UDP-Glc onto a glycan acceptor via alpha- or beta-glycosidic bonds. Glucosyltransferases can be found but are not limited to the GT1, GT4 and GT25 CAZy families. Mannosyltransferases are glycosyltransferases that transfer a mannose group (Man) from a GDP-mannose (GDP-Man) donor onto a glycan acceptor. Mannosyltransferases comprise alpha-1,2-mannosyltransferases, alpha-1,3-mannosyltransferases and alpha-1,6-mannosyltransferases that transfer a Man residue from GDP-Man onto a glycan acceptor via alpha-glycosidic bonds. Mannosyltransferases can be found but are not limited to the GT22, GT39, GT62 and GT69 CAZy families. N-acetylglucosaminyltransferases are glycosyltransferases that transfer an N-acetylglucosamine group (GlcNAc) from an UDP-N-acetylglucosamine (UDP-GlcNAc) donor onto a glycan acceptor. N-acetylglucosaminyltransferases can be found but are not limited to GT2 and GT4 CAZy families.

N-acetylgalactosaminyltransferases are glycosyltransferases that transfer an N-acetylgalactosamine group (GalNAc) from an UDP-N-acetylgalactosamine (UDP-GalNAc) donor onto a glycan acceptor. N-acetylgalactosaminyltransferases can be found but are not limited to GT7, GT12 and GT27 CAZy families. N-acetylmannosaminyltransferases are glycosyltransferases that transfer an N-acetylmannosamine group (ManNAc) from an UDP-N-acetylmannosamine (UDP-ManNAc) donor onto a glycan acceptor. Xylosyltransferases are glycosyltransferases that transfer a xylose residue (Xyl) from an UDP-xylose (UDP-Xyl) donor onto a glycan acceptor. Xylosyltransferases can be found but are not limited to GT61 and GT77 CAZy families. Glucuronyltransferases are glycosyltransferases that transfer a glucuronate from an UDP-glucuronate donor onto a glycan acceptor via alpha- or beta-glycosidic bonds. Glucuronyltransferases can be found but are not limited to GT4, GT43 and GT93 CAZy families.

Galacturonyltransferases are glycosyltransferases that transfer a galacturonate from an UDP-galacturonate donor onto a glycan acceptor. N-glycolylneuraminyltransferases are glycosyltransferases that transfer an N-glycolylneuraminic acid group (Neu5Gc) from a CMP-Neu5Gc donor onto a glycan acceptor. Rhamnosyltransferases are glycosyltransferases that transfer a rhamnose residue from a GDP-rhamnose donor onto a glycan acceptor. Rhamnosyltransferases can be found but are not limited to the GT1, GT2 and GT102 CAZy families. N-acetylrhamnosyltransferases are glycosyltransferases that transfer an N-acetylrhamnosamine residue from an UDP-N-acetyl-L-rhamnosamine donor onto a glycan acceptor. UDP-4-amino-4,6-dideoxy-N-acetyl-beta-L-altrosamine transaminases are glycosyltransferases that use an UDP-2-acetamido-2,6-dideoxy-L-arabino-4-hexulose in the biosynthesis of pseudaminic acid, which is a sialic acid-like sugar that is used to modify flagellin. UDP-N-acetylglucosamine enolpyruvyl transferases (murA) are glycosyltransferases that transfer an enolpyruvyl group from phosphoenolpyruvate (PEP) to UDP-N-acetylglucosamine (UDPAG) to form UDP-N-acetylglucosamine enolpyruvate. Fucosaminyltransferases are glycosyltransferases that transfer an N-acetylfucosamine residue from a dTDP-N-acetylfucosamine or an UDP-N-acetylfucosamine donor onto a glycan acceptor.

The terms “nucleotide-sugar” or “activated sugar” as used herein refer to activated forms of monosaccharides. Examples of activated monosaccharides include but are not limited to UDP-galactose (UDP-Gal), UDP-N-acetylglucosamine (UDP-GlcNAc), UDP-N-acetylgalactosamine (UDP-GalNAc), UDP-N-acetylmannosamine (UDP-ManNAc), GDP-fucose (GDP-Fuc), GDP-mannose (GDP-Man), UDP-glucose (UDP-Glc), UDP-2-acetamido-2,6-dideoxy-L-arabino-4-hexulose, UDP-2-acetamido-2,6-dideoxy-L-lyxo-4-hexulose, UDP-N-acetyl-L-rhamnosamine (UDP-L-RhaNAc or UDP-2-acetamido-2,6-dideoxy-L-mannose), dTDP-N-acetylfucosamine, UDP-N-acetylfucosamine (UDP-L-FucNAc or UDP-2-acetamido-2,6-dideoxy-L-galactose), UDP-N-acetyl-L-pneumosamine (UDP-L-PneNAC or UDP-2-acetamido-2,6-dideoxy-L-talose), UDP-N-acetylmuramic acid, UDP-N-acetyl-L-quinovosamine (UDP-L-QuiNAc or UDP-2-acetamido-2,6-dideoxy-L-glucose), GDP-L-quinovose, CMP-N-acetylneuraminic acid (CMP-Neu5Ac), CMP-N-glycolylneuraminic acid (CMP-Neu5Gc), CMP-Neu4Ac, CMP-Neu5Ac9N₃, CMP-Neu4,5Ac₂, CMP-Neu5,7Ac₂, CMP-Neu5,9Ac₂, CMP-Neu5,7(8,9)Ac₂, UDP-glucuronate, GDP-rhamnose, or UDP-xylose. Nucleotide-sugars act as glycosyl donors in glycosylation reactions. Those reactions are catalyzed by glycosyltransferases.

“Oligosaccharide” as the term is used herein and as generally understood in the state of the art, refers to a saccharide polymer containing a small number, typically three to twenty, of simple sugars, i.e., monosaccharides. The monosaccharides as used herein are reducing sugars. The oligosaccharides can be reducing or non-reducing sugars and have a reducing and a non-reducing end. A reducing sugar is any sugar that is capable of reducing another compound and is oxidized itself, that is, the carbonyl carbon of the sugar is oxidized to a carboxyl group. The oligosaccharide as used in this disclosure can be a linear structure or can include branches. The linkage (e.g., glycosidic linkage, galactosidic linkage, glucosidic linkage, etc.) between two sugar units can be expressed, for example, as 1,4, 1->4, or (1-4), used interchangeably herein. For example, the terms “Gal-b1,4-Glc,” “β-Gal-(1->4)-Glc,” “Galbeta1-4-Glc” and “Gal-b(1-4)-Glc” have the same meaning, i.e., a beta-glycosidic bond links carbon-1 of galactose (Gal) with the carbon-4 of glucose (Glc). Each monosaccharide can be in the cyclic form (e.g., pyranose of furanose form). Linkages between the individual monosaccharide units may include alpha 1->2, alpha 1->3, alpha 1->4, alpha 1->6, alpha 2->1, alpha 2->3, alpha 2->4, alpha 2->6, beta 1->2, beta 1->3, beta 1->4, beta 1->6, beta 2->1, beta 2->3, beta 2->4, and beta 2->6. An oligosaccharide can contain both alpha- and beta-glycosidic bonds or can contain only beta-glycosidic bonds.

“Disaccharide” as the term is used herein and as generally understood in the state of the art, refers to a saccharide polymer containing two monosaccharides. Examples of disaccharides comprise lactose (Gal-b1,4-Glc), lacto-N-biose (Gal-b1,3-GlcNAc), N-acetyllactosamine (Gal-b1,4-GlcNAc), LacDiNAc (GalNAc-b1,4-GlcNAc), N-acetylgalactosaminylglucose (GalNAc-b1,4-Glc), Neu5Ac-a2,3-Gal, Neu5Ac-a2,6-Gal and fucopyranosyl-(1-4)-N-glycolylneuraminic acid (Fuc-(1-4)-Neu5Gc).

The term “monosaccharide” as used herein refers to a sugar that is not decomposable into simpler sugars by hydrolysis, is classed either an aldose or ketose, and contains one or more hydroxyl groups per molecule. Monosaccharides are saccharides containing only one simple sugar. Examples of monosaccharides comprise Hexose, D-Glucopyranose, D-Galactofuranose, D-Galactopyranose, L-Galactopyranose, D-Mannopyranose, D-Allopyranose, L-Altropyranose, D-Gulopyranose, L-Idopyranose, D-Talopyranose, D-Ribofuranose, D-Ribopyranose, D-Arabinofuranose, D-Arabinopyranose, L-Arabinofuranose, L-Arabinopyranose, D-Xylopyranose, D-Lyxopyranose, D-Erythrofuranose, D-Threofuranose, Heptose, L-glycero-D-manno-Heptopyranose (LDmanHep), D-glycero-D-manno-Heptopyranose (DDmanHep), 6-Deoxy-L-altropyranose, 6-Deoxy-D-gulopyranose, 6-Deoxy-D-talopyranose, 6-Deoxy-D-galactopyranose, 6-Deoxy-L-galactopyranose, 6-Deoxy-D-mannopyranose, 6-Deoxy-L-mannopyranose, 6-Deoxy-D-glucopyranose, 2-Deoxy-D-arabino-hexose, 2-Deoxy-D-erythro-pentose, 2,6-Dideoxy-D-arabino-hexopyranose, 3,6-Dideoxy-D-arabino-hexopyranose, 3,6-Dideoxy-L-arabino-hexopyranose, 3,6-Dideoxy-D-xylo-hexopyranose, 3,6-Dideoxy-D-ribo-hexopyranose, 2,6-Dideoxy-D-ribo-hexopyranose, 3,6-Dideoxy-L-xylo-hexopyranose, 2-Amino-2-deoxy-D-glucopyranose, 2-Amino-2-deoxy-D-galactopyranose, 2-Amino-2-deoxy-D-mannopyranose, 2-Amino-2-deoxy-D-allopyranose, 2-Amino-2-deoxy-L-altropyranose, 2-Amino-2-deoxy-D-gulopyranose, 2-Amino-2-deoxy-L-idopyranose, 2-Amino-2-deoxy-D-talopyranose, 2-Acetamido-2-deoxy-D-glucopyranose, 2-Acetamido-2-deoxy-D-galactopyranose, 2-Acetamido-2-deoxy-D-mannopyranose, 2-Acetamido-2-deoxy-D-allopyranose, 2-Acetamido-2-deoxy-L-altropyranose, 2-Acetamido-2-deoxy-D-gulopyranose, 2-Acetamido-2-deoxy-L-idopyranose, 2-Acetamido-2-deoxy-D-talopyranose, 2-Acetamido-2,6-dideoxy-D-galactopyranose, 2-Acetamido-2,6-dideoxy-L-galactopyranose, 2-Acetamido-2,6-dideoxy-L-mannopyranose, 2-Acetamido-2,6-dideoxy-D-glucopyranose, 2-Acetamido-2,6-dideoxy-L-altropyranose, 2-Acetamido-2,6-dideoxy-D-talopyranose, D-Glucopyranuronic acid, D-Galactopyranuronic acid, D-Mannopyranuronic acid, D-Allopyranuronic acid, L-Altropyranuronic acid, D-Gulopyranuronic acid, L-Gulopyranuronic acid, L-Idopyranuronic acid, D-Talopyranuronic acid, sialic acid, 5-Amino-3,5-dideoxy-D-glycero-D-galacto-non-2-ulosonic acid, 5-Acetamido-3,5-dideoxy-D-glycero-D-galacto-non-2-ulosonic acid, 5-Glycolylamido-3,5-dideoxy-D-glycero-D-galacto-non-2-ulosonic acid, Erythritol, Arabinitol, Xylitol, Ribitol, Glucitol, Galactitol, Mannitol, D-ribo-Hex-2-ulopyranose, D-arabino-Hex-2-ulofuranose (D-fructofuranose), D-arabino-Hex-2-ulopyranose, L-xylo-Hex-2-ulopyranose, D-lyxo-Hex-2-ulopyranose, D-threo-Pent-2-ulopyranose, D-altro-Hept-2-ulopyranose, 3-C-(Hydroxymethyl)-D-erythofuranose, 2,4,6-Trideoxy-2,4-diamino-D-glucopyranose, 6-Deoxy-3-O-methyl-D-glucose, 3-O-Methyl-D-rhamnose, 2,6-Dideoxy-3-methyl-D-ribo-hexose, 2-Amino-3-O-[(R)-1-carboxyethyl]-2-deoxy-D-glucopyranose, 2-Acetamido-3-O-[(R)-carboxyethyl]-2-deoxy-D-glucopyranose, 2-Glycolylamido-3-O-[(R)-1-carboxyethyl]-2-deoxy-D-glucopyranose, 3-Deoxy-D-lyxo-hept-2-ulopyranosaric acid, 3-Deoxy-D-manno-oct-2-ulopyranosonic acid, 3-Deoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid, 5,7-Diamino-3,5,7,9-tetradeoxy-L-glycero-L-manno-non-2-ulopyranosonic acid, 5,7-Diamino-3,5,7,9-tetradeoxy-L-glycero-L-altro-non-2-ulopyranosonic acid, 5,7-Diamino-3,5,7,9-tetradeoxy-D-glycero-D-galacto-non-2-ulopyranosonic acid, 5,7-Diamino-3,5,7,9-tetradeoxy-D-glycero-D-talo-non-2-ulopyranosonic acid, glucose, galactose, N-acetylglucosamine, glucosamine, mannose, xylose, N-acetylmannosamine, N-acetylneuraminic acid, N-glycolylneuraminic acid, N-acetylgalactosamine, galactosamine, fucose, rhamnose, glucuronic acid, gluconic acid, fructose and polyols.

With the term polyol is meant an alcohol containing multiple hydroxyl groups. For example, glycerol, sorbitol, or mannitol.

Oligosaccharides are glycan structures that are composed of three or more monosaccharide subunits that are linked to each other via glycosidic bonds in a linear or in a branched structure. Preferably, the oligosaccharide as described herein contains monosaccharides selected from the list as used herein above. Examples of oligosaccharides include but are not limited to Lewis-type antigen oligosaccharides, mammalian milk oligosaccharides and human milk oligosaccharides.

As used herein, “mammalian milk oligosaccharide” (MMO) refers to oligosaccharides such as but not limited to 3-fucosyllactose, 2′-fucosyllactose, 6-fucosyllactose, 2′,3-difucosyllactose, 2′,2-difucosyllactose, 3,4-difucosyllactose, 6′-sialyllactose, 3′-sialyllactose, 3,6-disialyllactose, 6,6′-disialyllactose, 8,3-disialyllactose, 3,6-disialyllacto-N-tetraose, lactodifucotetraose, lacto-N-tetraose, lacto-N-neotetraose, lacto-N-fucopentaose II, lacto-N-fucopentaose I, lacto-N-fucopentaose III, lacto-N-fucopentaose V, lacto-N-fucopentaose VI, sialyllacto-N-neotetraose c, sialyllacto-N-tetraose b, sialyllacto-N-tetraose a, lacto-N-difucohexaose I, lacto-N-difucohexaose II, lacto-N-hexaose, lacto-N-neohexaose, para-lacto-N-hexaose, monofucosylmonosialyllacto-N-neotetraose c, monofucosyl para-lacto-N-hexaose, monofucosyllacto-N-hexaose III, isomeric fucosylated lacto-N-hexaose III, isomeric fucosylated lacto-N-hexaose I, sialyllacto-N-hexaose, sialyllacto-N-neohexaose II, difucosyl-para-lacto-N-hexaose, difucosyllacto-N-hexaose, difucosyllacto-N-hexaose a, difucosyllacto-N-hexaose c, galactosylated chitosan, fucosylated oligosaccharides, neutral oligosaccharide and/or sialylated oligosaccharides. Mammalian milk oligosaccharides (MMOs) comprise oligosaccharides present in milk found in any phase during lactation including colostrum milk from humans (i.e., human milk oligosaccharides or HMOs) and mammals including but not limited to cows (Bos Taurus), sheep (Ovis aries), goats (Capra aegagrus hircus), bactrian camels (Camelus bactrianus), horses (Equus ferus caballus), pigs (Sus scropha), dogs (Canis lupus familiaris), ezo brown bears (Ursus arctos yesoensis), polar bear (Ursus maritimus), Japanese black bears (Ursus thibetanus japonicus), striped skunks (Mephitis mephitis), hooded seals (Cystophora cristata), Asian elephants (Elephas maximus), African elephant (Loxodonta africana), giant anteater (Myrmecophaga tridactyla), common bottlenose dolphins (Tursiops truncates), northern minke whales (Balaenoptera acutorostrata), tammar wallabies (Macropus eugenii), red kangaroos (Macropus rufus), common brushtail possum (Trichosurus Vulpecula), koalas (Phascolarctos cinereus), eastern quolls (Dasyurus viverrinus), platypus (Ornithorhynchus anatinus). Human milk oligosaccharides (HMOs) are also known as human identical milk oligosaccharides that are chemically identical to the human milk oligosaccharides found in human breast milk but that are biotechnologically-produced (e.g., using cell free systems or cells and organisms comprising a bacterium, a fungus, a yeast, a plant, animal, or protozoan cell, preferably genetically engineered cells and organisms). Human identical milk oligosaccharides are marketed under the name HiMO.

As used herein the term “Lewis-type antigens” comprise the following oligosaccharides: H1 antigen, which is Fucα1-2Galβ1-3GlcNAc, or in short 2′FLNB; Lewisa, which is the trisaccharide Galβ1-3[Fucα1-4]GlcNAc, or in short 4-FLNB; Lewisb, which is the tetrasaccharide Fucα1-2Galβ1-3[Fucα1-4]GlcNAc, or in short DiF-LNB; sialyl Lewisa, which is 5-acetylneuraminyl-(2-3)-galactosyl-(1-3)-(fucopyranosyl-(1-4))-N-acetylglucosamine, or written in short Neu5Acα2-3Galβ1-3[Fucα1-4]GlcNAc; H2 antigen, which is Fucα1-2Galβ1-4GlcNAc, or otherwise stated 2′fucosyl-N-acetyl-lactosamine, in short 2′FLacNAc; Lewisx, which is the trisaccharide Galβ1-4[Fucα1-3]GlcNAc, or otherwise known as 3-Fucosyl-N-acetyl-lactosamine, in short 3-FLacNAc, Lewisy, which is the tetrasaccharide Fucα1-2Galβ1-4[Fucα1-3]GlcNAc and sialyl Lewisx, which is 5-acetylneuraminyl-(2-3)-galactosyl-(1-4)-(fucopyranosyl-(1-3))-N-acetylglucosamine, or written in short Neu5Acα2-3Galβ1-4[Fucα1-3]GlcNAc.

A ‘fucosylated oligosaccharide’ as used herein and as generally understood in the state of the art is an oligosaccharide that is carrying a fucose-residue. Such fucosylated oligosaccharide is a saccharide structure comprising at least three monosaccharide subunits linked to each other via glycosidic bonds, wherein at least one of the monosaccharide subunit is a fucose. A fucosylated oligosaccharide can contain more than one fucose residue, e.g., two, three or more. A fucosylated oligosaccharide can be a neutral oligosaccharide or a charged oligosaccharide e.g., also comprising sialic acid structures. Fucose can be linked to other monosaccharide subunits comprising glucose, galactose, GlcNAc via alpha-glycosidic bonds comprising alpha-1,2 alpha-1,3, alpha-1,4, alpha-1,6 linkages.

Examples comprise 2′-fucosyllactose (2′FL), 3-fucosyllactose (3FL), 4-fucosyllactose (4FL), 6-fucosyllactose (6FL), difucosyllactose (diFL), lactodifucotetraose (LDFT), Lacto-N-fucopentaose I (LNFP I), Lacto-N-fucopentaose II (LNFP II), Lacto-N-fucopentaose III (LNFP III), lacto-N-fucopentaose V (LNFP V), lacto-N-fucopentaose VI (LNFP VI), lacto-N-neofucopentaose I, lacto-N-difucohexaose I (LDFH I), lacto-N-difucohexaose II (LDFH II), Monofucosyllacto-N-hexaose III (MFLNH III), Difucosyllacto-N-hexaose (DFLNHa), difucosyl-lacto-N-neohexaose.

The terms “alpha-1,2-fucosyltransferase,” “alpha 1,2 fucosyltransferase,” “2-fucosyltransferase, “α-1,2-fucosyltransferase,” “α 1,2 fucosyltransferase,” “2 fucosyltransferase, “2-FT” or “2FT” as used in this disclosure, are used interchangeably and refer to a glycosyltransferase that catalyzes the transfer of fucose from the donor GDP-L-fucose, to the acceptor molecule in an alpha-1,2-linkage. The terms “2′ fucosyllactose,” “2′-fucosyllactose,” “alpha-1,2-fucosyllactose,” “alpha 1,2 fucosyllactose,” “α-1,2-fucosyllactose,” “α 1,2 fucosyllactose,” “Galβ-4(Fucα1-2)Glc,” 2FL” or “2′FL” as used in this disclosure, are used interchangeably and refer to the product obtained by the catalysis of the alpha-1,2-fucosyltransferase transferring the fucose residue from GDP-L-fucose to lactose in an alpha-1,2-linkage. The terms “difucosyllactose,” “di-fucosyllactose,” “lactodifucotetraose,” “2′,3-difucosyllactose,” “2′,3 difucosyllactose,” “α-2′,3-fucosyllactose,” “α 2′,3 fucosyllactose, “Fucα1-2Galβ1-4(Fucα1-3)Glc,” “DFLac,” 2′,3 diFL,” “DFL,” “DiFL” or “diFL” as used in this disclosure, are used interchangeably.

The terms “alpha-1,3-fucosyltransferase,” “alpha 1,3 fucosyltransferase,” “3-fucosyltransferase, “α-1,3-fucosyltransferase,” “α 1,3 fucosyltransferase,” “3 fucosyltransferase, “3-FT” or “3FT” as used in this disclosure, are used interchangeably and refer to a glycosyltransferase that catalyzes the transfer of fucose from the donor GDP-L-fucose, to the acceptor molecule in an alpha-1,3-linkage. The terms “3-fucosyllactose,” “alpha-1,3-fucosyllactose,” “alpha 1,3 fucosyllactose,” “α-1,3-fucosyllactose,” “α 1,3 fucosyllactose,” “Galβ-4(Fucα1-3)Glc,” 3FL″ or “3-FL” as used in this disclosure, are used interchangeably and refer to the product obtained by the catalysis of the alpha-1,3-fucosyltransferase transferring the fucose residue from GDP-L-fucose to lactose in an alpha-1,3-linkage.

As used herein, a ‘sialylated oligosaccharide’ is to be understood as a charged sialic acid containing oligosaccharide, i.e., an oligosaccharide having a sialic acid residue. It has an acidic nature. A sialylated oligosaccharide contains at least one sialic acid monosaccharide subunit, like e.g., but not limited to Neu5Ac and Neu5Gc. The sialylated oligosaccharide is a saccharide structure comprising at least three monosaccharide subunits linked to each other via glycosidic bonds, wherein at least one of the monosaccharide subunit is a sialic acid. The sialylated oligosaccharide can contain more than one sialic acid residue, e.g., two, three or more. The sialic acid can be linked to other monosaccharide subunits comprising galactose, GlcNAc, sialic acid, via alpha-glycosidic bonds comprising alpha-2,3, alpha-2,6 linkages. Some examples are 3-SL (3′-sialyllactose or 3′-SL or Neu5Ac-a2,3-Gal-b1,4-Glc), 3′-sialyllactosamine, 6-SL (6′-sialyllactose or 6′-SL or Neu5Ac-a2,6-Gal-b1,4-Glc), 6′-sialyllactosamine, oligosaccharides comprising 6′-sialyllactose, 3,6-disialyllactose (Neu5Ac-a2,3-(Neu5Ac-a2,6)-Gal-b1,4-Glc), 6,6′-disialyllactose (Neu5Ac-a2,6-Gal-b1,4-(Neu5Ac-a2,6)-Glc), 8,3-disialyllactose (Neu5Ac-a2,8-Neu5Ac-a2,3-Gal-b1,4-Glc), SGG hexasaccharide (Neu5Acα-2,3Galβ-1,3GalNacβ-1,3Gala-1,4Galβ-1,4Gal), sialylated tetrasaccharide (Neu5Acα-2,3Galβ-1,4GlcNacβ-14GlcNAc), pentasaccharide LSTD (Neu5Acα-2,3Galβ-1,4GlcNacβ-1,3Galβ-1,4Glc), sialylated lacto-N-triose, sialylated lacto-N-tetraose, sialyllacto-N-neotetraose, monosialyllacto-N-hexaose, disialyllacto-N-hexaose I, monosialyllacto-N-neohexaose I, monosialyllacto-N-neohexaose II, disialyllacto-N-neohexaose, disialyllacto-N-tetraose, disialyllacto-N-hexaose II, sialyllacto-N-tetraose a, disialyllacto-N-hexaose I, sialyllacto-N-tetraose b, sialyllacto-N-neotetraose c, sialyllacto-N-neotetraose d, 3′-sialyl-3-fucosyllactose, di sialomonofucosyllacto-N-neohexaose, monofucosylmonosialyllacto-N-octaose (sialyl Lea), sialyllacto-N-fucohexaose II, disialyllacto-N-fucopentaose II, monofucosyldisialyllacto-N-tetraose and oligosaccharides bearing one or several sialic acid residue(s), including but not limited to: oligosaccharide moieties of the gangliosides selected from GM3 (3′ sialyllactose, Neu5Acα-2,3Galβ-4Glc) and oligosaccharides comprising the GM3 motif, GD3 Neu5Acα-2,8Neu5Acα-2,3Galβ-1,4Glc GT3 (Neu5Aca-2,8Neu5Acα-2,8Neu5Acα-2,3Galβ-1,4Glc); GM2 GalNAcβ-1,4(Neu5Acα-2,3)Galβ-1,4Glc, GM1 Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,3)Galβ-1,4Glc, GD 1a Neu5Acα-2,3Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,3)Galβ-1,4Glc, GT1a Neu5Acα-2,8Neu5Acα-2,3Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,3)Galβ-1,4Glc, GD2 GalNAcβ-1,4(Neu5Acα-2,8Neu5Acα2,3)Galβ-1,4Glc, GT2 GalNAcβ-1,4(Neu5Acα-2, 8Neu5Acα-2, 8Neu5Acα2,3)Galβ-1,4Glc, GD1b, Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,8Neu5Acα2,3)Galβ-1,4Glc, GT1b Neu5Acα-2,3Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,8Neu5Acα2,3)Galβ-1,4Glc, GQ1b Neu5Acα-2,8Neu5Acα-2,3Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,8Neu5Acα2,3)Galβ-1,4Glc, GT1c Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,8Neu5Acα-2,8Neu5Acα2,3)Galβ-1,4Glc, GQ1c Neu5Acα-2,3Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,8Neu5Acα-2,8Neu5Acα2,3)Galβ-1,4Glc, GP1c Neu5Acα-2,8Neu5Aca-2,3Galβ-1,3GalNAc β-1,4(Neu5Acα-2,8Neu5Acα-2,8Neu5Acα2,3)Galβ-1,4Glc, GD1a Neu5Acα-2,3Galβ-1,3(Neu5Acα-2,6)GalNAcβ-1,4Galβ-1,4Glc, Fucosyl-GM1 Fuca-1,2Galβ-1,3GalNAcβ-1,4(Neu5Acα-2,3)Galβ-1,4Glc; all of which may be extended to the production of the corresponding gangliosides by reacting the above oligosaccharide moieties with ceramide or synthetizing the above oligosaccharides on a ceramide.

The terms “alpha-2,3-sialyltransferase,” “alpha 2,3 sialyltransferase,” “3-sialyltransferase, “α-2,3-sialyltransferase,” “α 2,3 sialyltransferase,” “3 sialyltransferase, “3-ST” or “3 ST” as used in this disclosure, are used interchangeably and refer to a glycosyltransferase that catalyzes the transfer of sialic acid from the donor CMP-Neu5Ac, to the acceptor molecule in an alpha-2,3-linkage. The terms “3′ sialyllactose,” “3′-sialyllactose,” “alpha-2,3-sialyllactose,” “alpha 2,3 sialyllactose,” “α-2,3-sialyllactose,” “α 2,3 sialyllactose,” 3SL″ or “3′SL” as used in this disclosure, are used interchangeably and refer to the product obtained by the catalysis of the alpha-2,3-fucosyltransferase transferring the sialic acid group from CMP-Neu5Ac to lactose in an alpha-2,3-linkage. The terms “alpha-2,6-sialyltransferase,” “alpha 2,6 sialyltransferase,” “6-sialyltransferase, “α-2,6-sialyltransferase,” “α 2,6 sialyltransferase,” “6 sialyltransferase, “6-ST” or “6ST” as used in this disclosure, are used interchangeably and refer to a glycosyltransferase that catalyzes the transfer of sialic acid from the donor CMP-Neu5Ac, to the acceptor in an alpha-2,6-linkage. The terms “6′ sialyllactose,” “6′-sialyllactose,” “alpha-2,6-sialyllactose,” “alpha 2,6 sialyllactose,” “α-2,6-sialyllactose,” “α 2,6 sialyllactose,” 6SL″ or “6′SL” as used in this disclosure, are used interchangeably and refer to the product obtained by the catalysis of the alpha-2,6-fucosyltransferase transferring the sialic acid group from CMP-Neu5Ac to lactose in an alpha-2,6-linkage. The terms “alpha-2,8-sialyltransferase,” “alpha 2,8 sialyltransferase,” “8-sialyltransferase, “α-2,8-sialyltransferase,” “α 2,8 sialyltransferase,” “8 sialyltransferase, “8-ST” or “8ST” as used in this disclosure, are used interchangeably and refer to a glycosyltransferase that catalyzes the transfer of sialic acid from the donor CMP-Neu5Ac, to the acceptor in an alpha-2,8-linkage.

A ‘neutral oligosaccharide’ as used herein and as generally understood in the state of the art is an oligosaccharide that has no negative charge originating from a carboxylic acid group. Examples of such neutral oligosaccharide comprise 2′-fucosyllactose (2′FL), 3-fucosyllactose (3FL), 2′, 3-difucosyllactose (diFL), lacto-N-triose II, lacto-N-tetraose, lacto-N-neotetraose, lacto-N-fucopentaose I, lacto-N-neofucopentaose I, lacto-N-fucopentaose II, lacto-N-fucopentaose III, lacto-N-fucopentaose V, lacto-N-fucopentaose VI, lacto-N-neofucopentaose V, lacto-N-difucohexaose I, lacto-N-difucohexaose II, 6′-galactosyllactose, 3′-galactosyllactose, lacto-N-hexaose, lacto-N-neohexaose, para-lacto-N-hexaose, para-lacto-N-neohexaose, difucosyl-lacto-N-hexaose and difucosyl-lacto-N-neohexaose.

As used herein, an antigen of the human ABO blood group system is an oligosaccharide. Such antigens of the human ABO blood group system are not restricted to human structures. The structures involve the A determinant GalNAc-alpha1,3(Fuc-alpha1,2)-Gal-, the B determinant Gal-alpha1,3(Fuc-alpha1,2)-Gal- and the H determinant Fuc-alpha1,2-Gal- that are present on disaccharide core structures comprising Gal-beta1,3-GlcNAc, Gal-beta1,4-GlcNAc, Gal-beta1,3-GalNAc and Gal-beta1,4-Glc.

The terms “LNT II,” “LNT-II,” “LN3,” “lacto-N-triose II,” “lacto-N-triose II,” “lacto-N-triose,” “lacto-N-triose” or “GlcNAβ1-3Galβ1-4Glc” as used in this disclosure, are used interchangeably.

The terms “LNT,” “lacto-N-tetraose,” “lacto-N-tetraose” or “Galβ1-3GlcNAβ1-3Galβ1-4Glc” as used in this disclosure, are used interchangeably.

The terms “LNnT,” “lacto-N-neotetraose,” “lacto-N-neotetraose,” “neo-LNT” or “Galβ1-4GlcNAβ1-3Galβ1-4Glc” as used in this disclosure, are used interchangeably.

The terms “LSTa,” “LS-Tetrasaccharide a,” “Sialyl-lacto-N-tetraose a,” “sialyllacto-N-tetraose a” or “Neu5Ac-a2,3-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc” as used in this disclosure, are used interchangeably.

The terms “LSTb,” “LS-Tetrasaccharide b,” “Sialyl-lacto-N-tetraose b,” “sialyllacto-N-tetraose b” or “Gal-b1,3-(Neu5Ac-a2,6)-GlcNAc-b1,3-Gal-b1,4-Glc” as used in this disclosure, are used interchangeably.

The terms “LSTc,” “LS-Tetrasaccharide c,” “Sialyl-lacto-N-tetraose c,” “sialyllacto-N-tetraose c,” “sialyllacto-N-neotetraose c” or “Neu5Ac-a2,6-Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc” as used in this disclosure, are used interchangeably.

The terms “LSTd,” “LS-Tetrasaccharide d,” “Sialyl-lacto-N-tetraose d,” “sialyllacto-N-tetraose d,” “sialyllacto-N-neotetraose d” or “Neu5Ac-a2,3-Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc” as used in this disclosure, are used interchangeably.

The terms “DSLNnT” and “Disialyllacto-N-neotetraose” are used interchangeably and refer to Neu5Ac-a2,6-[Neu5Ac-a2,6-Gal-b1,4-GlcNAc-b1,3]-Gal-b1,4-Glc.

The terms “DSLNT” and “Disialyllacto-N-tetraose” are used interchangeably and refer to Neu5Ac-a2,6-[Neu5Ac-a2,3-Gal-b1,3-GlcNAc-b1,3]-Gal-b1,4-Glc. The terms “LNFP-I,” “lacto-N-fucopentaose I,” “LNFP I,” “LNF I OH type I determinant,” “LNF I,” “LNF1,” “LNF 1” and “Blood group H antigen pentaose type 1” are used interchangeably and refer to Fuc-a1,2-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc.

The terms “GalNAc-LNFP-I” and “blood group A antigen hexaose type I” are used interchangeably and refer to GalNAc-a1,3-(Fuc-a1,2)-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc.

The terms “LNFP-II” and “lacto-N-fucopentaose II” are used interchangeably and refer to Gal-b1,3-(Fuc-a1,4)-GlcNAc-b1,3-Gal-b1,4-Glc.

The terms “LNFP-III” and “lacto-N-fucopentaose III” are used interchangeably and refer to Gal-b1,4-(Fuc-a1,3)-GlcNAc-b1,3-Gal-b1,4-Glc.

The terms “LNFP-V” and “lacto-N-fucopentaose V” are used interchangeably and refer to Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-(Fuc-a1,3)-Glc.

The terms “LNFP-VI,” “LNnFP V” and “lacto-N-neofucopentaose V” are used interchangeably and refer to Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-(Fuc-a1,3)-Glc.

The terms “LNnFP I” and “Lacto-N-neofucopentaose I” are used interchangeably and refer to Fuc-a1,2-Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc.

The terms “LNDFH I,” “Lacto-N-difucohexaose I,” “LNDFH-I,” “LDFH I,” “Le^b-lactose” and “Lewis-b hexasaccharide” are used interchangeably and refer to Fuc-a1,2-Gal-b1,3-[Fuc-a1,4]-GlcNAc-b1,3-Gal-b1,4-Glc.

The terms “LNDFH II,” “Lacto-N-difucohexaose II,” “Lewis a-Lewis x” and “LDFH II” are used interchangeably and refer to Fuc-a1,4-(Gal-b1,3)-GlcNAc-b1,3-Gal-b1,4-(Fuc-a1,3)-Glc.

The terms “LNnDFH,” “Lacto-N-neoDiFucohexaose” and “Lewis x hexaose” are used interchangeably and refer to Gal-b1,4-(Fuc-a1,3)-GlcNAc-b1,3-Gal-b1,4-(Fuc-a1,3)-Glc.

The terms “alpha-tetrasaccharide” and “A-tetrasaccharide” are used interchangeably and refer to GalNAc-a1,3-(Fuc-a1,2)-Gal-b1,4-Glc.

A ‘fucosylation pathway’ as used herein is a biochemical pathway comprising the enzymes and their respective genes, mannose-6-phosphate isomerase, phosphomannomutase, mannose-1-phosphate guanylyltransferase, GDP-mannose 4,6-dehydratase, GDP-L-fucose synthase and/or the salvage pathway L-fucokinase/GDP-fucose pyrophosphorylase, combined with a fucosyltransferase leading to α 1,2; α 1,3 α 1,4 or α 1,6 fucosylated oligosaccharides.

A ‘sialylation pathway’ is a biochemical pathway comprising the enzymes and their respective genes, L-glutamine-D-fructose-6-phosphate aminotransferase, glucosamine-6-phosphate deaminase, phosphoglucosamine mutase, N-acetylglucosamine-6-phosphate deacetylase, N-acetylglucosamine epimerase, UDP-N-acetylglucosamine 2-epimerase, N-acetylglucosamine-6P 2-epimerase, Glucosamine 6-phosphate N-acetyltransferase, N-AcetylGlucosamine-6-phosphate phosphatase, N-acetylmannosamine-6-phosphate phosphatase, N-acetylmannosamine kinase, phosphoacetylglucosamine mutase, N-acetylglucosamine-1-phosphate uridyltransferase, glucosamine-1-phosphate acetyltransferase, sialic acid synthase, N-acetylneuraminate lyase, N-acylneuraminate-9-phosphate synthase, N-acylneuraminate-9-phosphate phosphatase, and/or CMP-sialic acid synthase, combined with a sialyltransferase leading to α 2,3; α 2,6 or α 2,8 sialylated oligosaccharides.

A ‘galactosylation pathway’ as used herein is a biochemical pathway comprising the enzymes and their respective genes, galactose-1-epimerase, galactokinase, glucokinase, galactose-1-phosphate uridylyltransferase, UDP-glucose 4-epimerase, glucose-1-phosphate uridylyltransferase, and/or glucophosphomutase, combined with a galactosyltransferase leading to an alpha or beta bound galactose on the 2, 3, 4, 6 hydroxyl group of an oligosaccharide.

An ‘N-acetylglucosamine carbohydrate pathway’ as used herein is a biochemical pathway comprising the enzymes and their respective genes, L-glutamine-D-fructose-6-phosphate aminotransferase, glucosamine-6-phosphate deaminase, phosphoglucosamine mutase, N-acetylglucosamine-6-phosphate deacetylase, glucosamine 6-phosphate N-acetyltransferase, N-acetylglucosamine-1-phosphate uridylyltransferase, glucosamine-1-phosphate acetyltransferase, and/or glucosamine-1-phosphate acetyltransferase, combined with a glycosyltransferase leading to an alpha or beta bound N-acetylglucosamine on the 3, 4, 6 hydroxyl group of an oligosaccharide.

An ‘N-acetylgalactosaminylation pathway’ as used herein is a biochemical pathway comprising at least one of the enzymes and their respective genes chosen from the list comprising L-glutamine-D-fructose-6-phosphate aminotransferase, phosphoglucosamine mutase, N-acetylglucosamine 1-phosphate uridylyltransferase, glucosamine-1-phosphate acetyltransferase, UDP-N-acetylglucosamine 4-epimerase, UDP-glucose 4-epimerase, N-acetylgalactosamine kinase and/or UDP-N-acetylgalactosamine pyrophosphorylase combined with a glycosyltransferase leading to a GalNAc-modified compound comprising a mono-, di- or oligosaccharide having an alpha or beta bound N-acetylgalactosamine on the mono-, di- or oligosaccharide.

A ‘mannosylation pathway’ as used herein is a biochemical pathway comprising at least one of the enzymes and their respective genes chosen from the list comprising mannose-6-phosphate isomerase, phosphomannomutase and/or mannose-1-phosphate guanylyltransferase combined with a glycosyltransferase leading to a mannosylated compound comprising a mono-, di- or oligosaccharide having an alpha or beta bound mannose on the mono-, di- or oligosaccharide.

An ‘N-acetylmannosaminylation pathway’ as used herein is a biochemical pathway comprising at least one of the enzymes and their respective genes chosen from the list comprising L-glutamine-D-fructose-6-phosphate aminotransferase, glucosamine-6-phosphate deaminase, phosphoglucosamine mutase, N-acetylglucosamine-6-phosphate deacetylase, glucosamine 6-phosphate N-acetyltransferase, N-acetylglucosamine-1-phosphate uridyltransferase, glucosamine-1-phosphate acetyltransferase, glucosamine-1-phosphate acetyltransferase, UDP-GlcNAc 2-epimerase and/or ManNAc kinase combined with a glycosyltransferase leading to a ManNAc-modified compound comprising a mono-, di- or oligosaccharide having an alpha or beta bound N-acetylmannosamine on the mono-, di- or oligosaccharide.

The terms “mannose-6-phosphate isomerase,” “phosphomannose isomerase,” “mannose phosphate isomerase,” “phosphohexoisomerase,” “phosphomannoisomerase,” “phosphomannose-isomerase,” “phosphohexomutase,” “D-mannose-6-phosphate ketol-isomerase” and “manA” are used interchangeably and refer to an enzyme that catalyzes the reversible conversion of D-fructose 6-phosphate to D-mannose 6-phosphate.

The terms “phosphomannomutase,” “mannose phosphomutase,” “phosphomannose mutase,” “D-mannose 1,6-phosphomutase” and “manB” are used interchangeably and refer to an enzyme that catalyzes the reversible conversion of D-mannose 6-phosphate to D-mannose 1-phosphate.

The terms “mannose-1-phosphate guanylyltransferase,” “GTP-mannose-1-phosphate guanylyltransferase,” “PIM-GMP (phosphomannose isomerase-guanosine 5′-diphospho-D-mannose pyrophosphorylase),” “GDP-mannose pyrophosphorylase,” “guanosine 5′-diphospho-D-mannose pyrophosphorylase,” “guanosine diphosphomannose pyrophosphorylase,” “guanosine triphosphate-mannose 1-phosphate guanylyltransferase,” “mannose 1-phosphate guanylyltransferase (guanosine triphosphate)” and “manC” are used interchangeably and refer to an enzyme that converts D-mannose-1-phosphate using GTP into GDP-mannose and diphosphate.

The terms “GDP-mannose 4,6-dehydratase,” “guanosine 5′-diphosphate-D-mannose oxidoreductase,” “guanosine diphosphomannose oxidoreductase,” “guanosine diphosphomannose 4,6-dehydratase,” “GDP-D-mannose dehydratase,” “GDP-D-mannose 4,6-dehydratase,” “GDP-mannose 4,6-hydro-lyase,” “GDP-mannose 4,6-hydro-lyase (GDP-4-dehydro-6-deoxy-D-mannose-forming)” and “gmd” are used interchangeably and refer to an enzyme that forms the first step in the biosynthesis of GDP-rhamnose and GDP-fucose.

The terms “GDP-L-fucose synthase,” “GDP-4-keto-6-deoxy-D-mannose-3,5-epimerase-4-reductase,” “GDP-L-fucose:NADP+4-oxidoreductase (3,5-epimerizing)” and “fcl” are used interchangeably and refer to an enzyme that forms the second step in the biosynthesis of GDP-fucose.

The terms “L-fucokinase/GDP-fucose pyrophosphorylase,” “L-fucokinase/L-fucose-1-P guanylyltransferase,” “GDP-fucose pyrophosphorylase,” “GDP-L-fucose pyrophosphorylase,” and “fkp” are used interchangeably and refer to an enzyme that catalyzes the conversion of L-fucose-1-phosphate into GDP-fucose using GTP.

The terms “L-glutamine-D-fructose-6-phosphate aminotransferase,” “glutamine-fructose-6-phosphate transaminase (isomerizing),” “hexosephosphate aminotransferase,” “glucosamine-6-phosphate isomerase (glutamine-forming),” “glutamine-fructose-6-phosphate transaminase (isomerizing),” “D-fructose-6-phosphate amidotransferase,” “glucosaminephosphate isomerase,” “glucosamine 6-phosphate synthase,” “GlcN6P synthase,” “GFA” and “glmS” are used interchangeably and refer to an enzyme that catalyzes the conversion of D-fructose-6-phosphate into D-glucosamine-6-phosphate using L-glutamine.

The terms “glucosamine-6-P deaminase,” “glucosamine-6-phosphate deaminase,” “GlcN6P deaminase,” “glucosamine-6-phosphate isomerase,” “glmD” and “nagB” are used interchangeably and refer to an enzyme that catalyzes the reversible isomerization-deamination of glucosamine-6-phosphate (GlcN6P) to form fructose-6-phosphate and an ammonium ion.

The terms “phosphoglucosamine mutase” and “glmM” are used interchangeably and refer to an enzyme that catalyzes the conversion of glucosamine-6-phosphate to glucosamine-1-phosphate. Phosphoglucosamine mutase can also catalyse the formation of glucose-6-P from glucose-1-P, although at a 1400-fold lower rate.

The terms “N-acetylglucosamine-6-P deacetylase,” “N-acetylglucosamine-6-phosphate deacetylase” and “nagA” are used interchangeably and refer to an enzyme that catalyzes the hydrolysis of the N-acetyl group of N-acetylglucosamine-6-phosphate (GlcNAc-6-P) to yield glucosamine-6-phosphate (GlcN6P) and acetate.

An N-acylglucosamine 2-epimerase is an enzyme that catalyzes the reaction N-acyl-D-glucosamine=N-acyl-D-mannosamine. Alternative names for this enzyme comprise N-acetylglucosamine 2-epimerase, N-acetyl-D-glucosamine 2-epimerase, GlcNAc 2-epimerase, N-acyl-D-glucosamine 2-epimerase and N-acetylglucosamine epimerase.

An UDP-N-acetylglucosamine 2-epimerase is an enzyme that catalyzes the reaction N-acetyl-D-glucosamine=N-acetylmannosamine. Alternative names for this enzyme comprise UDP-N-acylglucosamine 2-epimerase, UDP-GlcNAc-2-epimerase and UDP-N-acetyl-D-glucosamine 2-epimerase.

An N-acetylmannosamine-6-phosphate 2-epimerase is an enzyme that catalyzes the reaction N-acetyl-D-glucosamine 6-phosphate=N-acetyl-D-mannosamine 6-phosphate.

A bifunctional UDP-GlcNAc 2-epimerase/kinase is a bifunctional enzyme that catalyzes the reaction UDP-N-acetyl-D-glucosamine=N-acetyl-D-mannosamine and the reaction N-acetyl-D-mannosamine+ATP=ADP+N-acetyl-D-mannosamine 6-phosphate.

A glucosamine 6-phosphate N-acetyltransferase is an enzyme that catalyzes the transfer of an acetyl group from acetyl-CoA to D-glucosamine-6-phosphate thereby generating a free CoA and N-acetyl-D-glucosamine 6-phosphate. Alternative names comprise aminodeoxyglucosephosphate acetyltransferase, D-glucosamine-6-P N-acetyltransferase, glucosamine 6-phosphate acetylase, glucosamine 6-phosphate N-acetyltransferase, glucosaminephosphate N-acetyltransferase, glucosamine-6-phosphate acetylase, N-acetylglucosamine-6-phosphate synthase, phosphoglucosamine acetylase, phosphoglucosamine N-acetylase phosphoglucosamine N-acetylase, phosphoglucosamine transacetylase, GNA and GNA1.

The term “N-acetylglucosamine-6-phosphate phosphatase” refers to an enzyme that dephosphorylates N-acetylglucosamine-6-phosphate (GlcNAc-6-P) hereby synthesizing N-acetylglucosamine (GlcNAc).

The term “N-acetylmannosamine-6-phosphate phosphatase” refers to an enzyme that dephosphorylates N-acetylmannosamine-6-phosphate (ManNAc-6P) to N-acetylmannosamine (ManNAc).

The terms “N-acetylmannosamine-6-phosphate 2-epimerase,” “ManNAc-6-P isomerase,” “ManNAc-6-P 2-epimerase,” N-acetylglucosamine-6P 2-epimerase and “nanE” are used interchangeably and refer to an enzyme that converts ManNAc-6-P to N-acetylglucosamine-6-phosphate (GlcNAc-6-P).

The terms “phosphoacetylglucosamine mutase,” “acetylglucosamine phosphomutase,” “acetylaminodeoxyglucose phosphomutase,” “phospho-N-acetylglucosamine mutase” and “N-acetyl-D-glucosamine 1,6-phosphomutase” are used interchangeably and refer to an enzyme that catalyzes the conversion of N-acetyl-glucosamine 1-phosphate into N-acetylglucosamine 6-phosphate.

The terms “N-acetylglucosamine 1-phosphate uridylyltransferase,” “N-acetylglucosamine-1-phosphate uridyltransferase,” “UDP-N-acetylglucosamine diphosphorylase,” “UDP-N-acetylglucosamine pyrophosphorylase,” “uridine diphosphoacetylglucosamine pyrophosphorylase,” “UTP:2-acetamido-2-deoxy-alpha-D-glucose-1-phosphate uridylyltransferase,” “UDP-GlcNAc pyrophosphorylase,” “GlmU uridylyltransferase,” “Acetylglucosamine 1-phosphate uridylyltransferase,” “UDP-acetylglucosamine pyrophosphorylase,” “uridine diphosphate-N-acetylglucosamine pyrophosphorylase,” “uridine diphosphoacetylglucosamine phosphorylase,” and “acetylglucosamine 1-phosphate uridylyltransferase” are used interchangeably and refer to an enzyme that catalyzes the conversion of N-acetylglucosamine 1-phosphate (GlcNAc-1-P) into UDP-N-acetylglucosamine (UDP-GlcNAc) by the transfer of uridine 5-monophosphate (from uridine 5-triphosphate (UTP)).

The term glucosamine-1-phosphate acetyltransferase refers to an enzyme that catalyzes the transfer of the acetyl group from acetyl coenzyme A to glucosamine-1-phosphate (GlcN-1-P) to produce N-acetylglucosamine-1-phosphate (GlcNAc-1-P).

The term “glmU” refers to a bifunctional enzyme that has both N-acetylglucosamine-1-phosphate uridyltransferase and glucosamine-1-phosphate acetyltransferase activity and that catalyzes two sequential reactions in the de novo biosynthetic pathway for UDP-GlcNAc. The C-terminal domain catalyzes the transfer of acetyl group from acetyl coenzyme A to GlcN-1-P to produce GlcNAc-1-P, which is converted into UDP-GlcNAc by the transfer of uridine 5-monophosphate, a reaction catalyzed by the N-terminal domain.

The terms “NeunAc synthase,” “N-acetylneuraminic acid synthase,” “N-acetylneuraminate synthase,” “sialic acid synthase,” “NeuAc synthase,” “NeuB,” “NeuB 1,” “NeuNAc synthase,” “NANA condensing enzyme,” “N-acetylneuraminate lyase synthase,” “N-acetylneuraminic acid condensing enzyme” as used herein are used interchangeably and refer to an enzyme capable to synthesize sialic acid from N-acetylmannosamine (ManNAc) in a reaction using phosphoenolpyruvate (PEP).

The terms “N-acetylneuraminate lyase,” “Neu5Ac lyase,” “N-acetylneuraminate pyruvate-lyase,” “N-acetylneuraminic acid aldolase,” “NALase,” “sialate lyase,” “sialic acid aldolase,” “sialic acid lyase” and “nanA” are used interchangeably and refer to an enzyme that degrades N-acetylneuraminate into N-acetylmannosamine (ManNAc) and pyruvate.

The terms “N-acylneuraminate-9-phosphate synthase,” “N-acylneuraminate-9-phosphate synthetase,” “NANA synthase,” “NANAS,” “NANS,” “NmeNANAS,” “N-acetylneuraminate pyruvate-lyase (pyruvate-phosphorylating)” as used herein are used interchangeably and refer to an enzyme capable to synthesize N-acylneuraminate-9-phosphate from N-acetylmannosamine-6-phosphate (ManNAc-6-phosphate) in a reaction using phosphoenolpyruvate (PEP).

The term “N-acylneuraminate-9-phosphatase” refers to an enzyme capable to dephosphorylate N-acylneuraminate-9-phosphate to synthesize N-acylneuraminate.

The terms “CMP-sialic acid synthase,” “N-acylneuraminate cytidylyltransferase,” “CMP-sialate synthase,” “CMP-NeuAc synthase,” “NeuA” and “CMP-N-acetylneuraminic acid synthase” as used herein are used interchangeably and refer to an enzyme capable to synthesize CMP-N-acetylneuraminate from N-acetylneuraminate using CTP in the reaction.

The terms “galactose-1-epimerase,” “aldose 1-epimerase,” “mutarotase,” “aldose mutarotase,” “galactose mutarotase,” “galactose 1-epimerase” and “D-galactose 1-epimerase” are used interchangeably and refer to an enzyme that catalyzes the conversion of beta-D-galactose into alpha-D-galactose.

The terms “galactokinase,” “galactokinase (phosphorylating)” and “ATP:D-galactose-1-phosphotransferase” are used interchangeably and refer to an enzyme that catalyzes the conversion of alpha-D-galactose into alpha-D-galactose 1-phosphate using ATP.

The terms glucokinase, and “glucokinase (phosphorylating)” are used interchangeably and refer to an enzyme that catalyzes the conversion of D-glucose into D-glucose 6-phosphate using ATP.

The terms “galactose-1-phosphate uridylyltransferase,” “Gal-1-P uridylyltransferase,” “UDP-glucose-hexose-1-phosphate uridylyltransferase,” “uridyl transferase,” “hexose-1-phosphate uridylyltransferase,” “uridyltransferase”; “hexose 1-phosphate uridyltransferase,” “UDP-glucose:alpha-D-galactose-1-phosphate uridylyltransferase,” “galB” and “galT” are used interchangeably and refer to an enzyme that catalyzes the reaction D-galactose 1-phosphate+UDP-D-glucose=D-glucose 1-phosphate+UDP-D-galactose.

The terms “UDP-glucose 4-epimerase,” “UDP-galactose 4-epimerase,” “uridine diphosphoglucose epimerase,” “galactowaldenase,” “UDPG-4-epimerase,” “uridine diphosphate galactose 4-epimerase,” “uridine diphospho-galactose-4-epimerase,” “UDP-glucose epimerase,” “4-epimerase,” “uridine diphosphoglucose 4-epimerase,” “uridine diphosphate glucose 4-epimerase” and “UDP-D-galactose 4-epimerase” are used interchangeably and refer to an enzyme that catalyzes the conversion of UDP-D-glucose into UDP-galactose.

The terms “glucose-1-phosphate uridylyltransferase,” “UTP-glucose-1-phosphate uridylyltransferase,” “UDP glucose pyrophosphorylase,” “UDPG phosphorylase,” “UDPG pyrophosphorylase,” “uridine 5′-diphosphoglucose pyrophosphorylase,” “uridine diphosphoglucose pyrophosphorylase,” “uridine diphosphate-D-glucose pyrophosphorylase,” “uridine-diphosphate glucose pyrophosphorylase” and “galU” are used interchangeably and refer to an enzyme that catalyzes the conversion of D-glucose-1-phosphate into UDP-glucose using UTP.

The terms “phosphoglucomutase (alpha-D-glucose-1,6-bisphosphate-dependent),” “glucose phosphomutase (ambiguous)” and “phosphoglucose mutase (ambiguous)” are used interchangeably and refer to an enzyme that catalyzes the conversion of D-glucose 1-phosphate into D-glucose 6-phosphate.

The terms “UDP-N-acetylglucosamine 4-epimerase,” “UDP acetylglucosamine epimerase,” “uridine diphosphoacetylglucosamine epimerase,” “uridine diphosphate N-acetylglucosamine-4-epimerase,” “uridine 5′-diphospho-N-acetylglucosamine-4-epimerase” and “UDP-N-acetyl-D-glucosamine 4-epimerase” are used interchangeably and refer to an enzyme that catalyzes the epimerization of UDP-N-acetylglucosamine (UDP-GlcNAc) to UDP-N-acetylgalactosamine (UDP-GalNAc).

The terms “N-acetylgalactosamine kinase,” “GALK2,” “GK2,” “GalNAc kinase,” “N-acetylgalactosamine (GalNAc)-1-phosphate kinase” and “ATP:N-acetyl-D-galactosamine 1-phosphotransferase” are used interchangeably and refer to an enzyme that catalyzes the synthesis of N-acetylgalactosamine 1-phosphate (GalNAc-1-P) from N-acetylgalactosamine (GalNAc) using ATP.

The terms “UDP-N-acetylgalactosamine pyrophosphorylase” and “UDP-GalNAc pyrophosphorylase” are used interchangeably and refer to an enzyme that catalyzes the conversion of N-acetylgalactosamine 1-phosphate (GalNAc-1-P) into UDP-N-acetylgalactosamine (UDP-GalNAc) using UTP.

The terms “N-acetylneuraminate kinase,” “ManNAc kinase,” “N-acetyl-D-mannosamine kinase” and “nanK” are used interchangeably and refer to an enzyme that phosphorylates ManNAc to synthesize N-acetylmannosamine-phosphate (ManNAc-6-P).

The terms “acetyl-coenzyme A synthetase,” “acs,” “acetyl-CoA synthetase,” “AcCoA synthetase,” “acetate-CoA ligase,” “acyl-activating enzyme” and “yfaC” are used interchangeably and refer to an enzyme that catalyzes the conversion of acetate into acetyl-coezyme A (AcCoA) in an ATP-dependent reaction.

The terms “pyruvate dehydrogenase,” “pyruvate oxidase,” “PDX,” “poxB” and “pyruvate:ubiquinone-8 oxidoreductase” are used interchangeably and refer to an enzyme that catalyzes the oxidative decarboxylation of pyruvate to produce acetate and CO₂.

The terms “lactate dehydrogenase,” “D-lactate dehydrogenase,” “ldhA,” “hslI,” “htpH,” “D-LDH,” “fermentative lactate dehydrogenase” and “D-specific 2-hydroxyacid dehydrogenase” are used interchangeably and refer to an enzyme that catalyzes the conversion of lactate into pyruvate hereby generating NADH.

As used herein, the term “cell productivity index (CPI)” refers to the mass of the product produced by the cells divided by the mass of the cells produced in the culture.

The term “purified” refers to material that is substantially or essentially free from components that interfere with the activity of the biological molecule. For cells, saccharides, nucleic acids, and polypeptides, the term “purified” refers to material that is substantially or essentially free from components that normally accompany the material as found in its native state. Typically, purified saccharides, oligosaccharides, proteins or nucleic acids of this disclosure are at least about 50%, 55%, 60%, 65%, 70%, 75%, 80% or 85% pure, usually at least about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% pure as measured by band intensity on a silver stained gel or other method for determining purity. Purity or homogeneity can be indicated by a number of means well known in the art, such as polyacrylamide gel electrophoresis of a protein or nucleic acid sample, followed by visualization upon staining. For certain purposes high resolution will be needed and HPLC or a similar means for purification utilized. For oligosaccharides, purity can be determined using methods such as but not limited to thin layer chromatography, gas chromatography, NMR, HPLC, capillary electrophoresis or mass spectroscopy.

The term “cultivation” refers to the culture medium wherein the cell is cultivated or fermented, the cell itself, and the oligosaccharides that are produced by the cell in whole broth, i.e., inside (intracellularly) as well as outside (extracellularly) of the cell.

The term “membrane transporter proteins” as used herein refers to proteins that are part of or interact with the cell membrane and control the flow of molecules and information across the cell. The membrane proteins are thus involved in transport, be it import into or export out of the cell.

Such membrane transporter proteins can be porters, P-P-bond-hydrolysis-driven transporters, β-Barrel Porins, auxiliary transport proteins, putative transport proteins and phosphotransfer-driven group translocators as defined by the Transporter Classification Database that is operated and curated by the Saier Lab Bioinformatics Group available via www.tcdb.org and providing a functional and phylogenetic classification of membrane transport proteins This Transporter Classification Database details a comprehensive IUBMB approved classification system for membrane transporter proteins known as the Transporter Classification (TC) system. The TCDB classification searches as described here are defined based on TCDB.org as released on 17 Jun. 2019.

Porters is the collective name of uniporters, symporters, and antiporters that utilize a carrier-mediated process (Saier et al., Nucleic Acids Res. 44 (2016) D372-D379). They belong to the electrochemical potential-driven transporters and are also known as secondary carrier-type facilitators. Membrane transporter proteins are included in this class when they utilize a carrier-mediated process to catalyse uniport when a single species is transported either by facilitated diffusion or in a membrane potential-dependent process if the solute is charged; antiport when two or more species are transported in opposite directions in a tightly coupled process, not coupled to a direct form of energy other than chemiosmotic energy; and/or symport when two or more species are transported together in the same direction in a tightly coupled process, not coupled to a direct form of energy other than chemiosmotic energy, of secondary carriers (Forrest et al., Biochim. Biophys. Acta 1807 (2011) 167-188). These systems are usually stereospecific. Solute:solute countertransport is a characteristic feature of secondary carriers. The dynamic association of porters and enzymes creates functional membrane transport metabolons that channel substrates typically obtained from the extracellular compartment directly into their cellular metabolism (Moraes and Reithmeier, Biochim. Biophys. Acta 1818 (2012), 2687-2706). Solutes that are transported via this porter system include but are not limited to cations, organic anions, inorganic anions, nucleosides, amino acids, polyols, phosphorylated glycolytic intermediates, osmolytes, siderophores.

Membrane transporter proteins are included in the class of P-P-bond hydrolysis-driven transporters if they hydrolyze the diphosphate bond of inorganic pyrophosphate, ATP, or another nucleoside triphosphate, to drive the active uptake and/or extrusion of a solute or solutes (Saier et al., Nucleic Acids Res. 44 (2016) D372-D379). The membrane transporter protein may or may not be transiently phosphorylated, but the substrate is not phosphorylated. Substrates that are transported via the class of P-P-bond hydrolysis-driven transporters include but are not limited to cations, heavy metals, beta-glucan, UDP-glucose, lipopolysaccharides, teichoic acid.

The β-Barrel porins membrane transporter proteins form transmembrane pores that usually allow the energy independent passage of solutes across a membrane. The transmembrane portions of these proteins exclusively comprise β-strands that form a β-barrel (Saier et al., Nucleic Acids Res. 44 (2016) D372-D379). These porin-type proteins are found in the outer membranes of Gram-negative bacteria, mitochondria, plastids, and possibly acid-fast Gram-positive bacteria. Solutes that are transported via these β-Barrel porins include but are not limited to nucleosides, raffinose, glucose, beta-glucosides, oligosaccharides.

The auxiliary transport proteins are defined to be proteins that facilitate transport across one or more biological membranes but do not themselves participate directly in transport. These membrane transporter proteins always function in conjunction with one or more established transport systems such as but not limited to outer membrane factors (OMFs), polysaccharide (PST) porters, the ATP-binding cassette (ABC)-type transporters. They may provide a function connected with energy coupling to transport, play a structural role in complex formation, serve a biogenic or stability function or function in regulation (Saier et al., Nucleic Acids Res. 44 (2016) D372-D379). Examples of auxiliary transport proteins include but are not limited to the polysaccharide copolymerase family involved in polysaccharide transport, the membrane fusion protein family involved in bacteriocin and chemical toxin transport.

Putative transport protein comprises families that will either be classified elsewhere when the transport function of a member becomes established or will be eliminated from the Transporter Classification system if the proposed transport function is disproven. These families include a member or members for which a transport function has been suggested, but evidence for such a function is not yet compelling (Saier et al., Nucleic Acids Res. 44 (2016) D372-D379). Examples of putative transporters classified in this group under the TCDB system as released on 17 Jun. 2019 include but are not limited to copper transporters.

The phosphotransfer-driven group translocators are also known as the PEP-dependent phosphoryl transfer-driven group translocators of the bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS). The product of the reaction, derived from extracellular sugar, is a cytoplasmic sugar-phosphate. The enzymatic constituents, catalyzing sugar phosphorylation, are superimposed on the transport process in a tightly coupled process. The PTS system is involved in many different aspects comprising in regulation and chemotaxis, biofilm formation, and pathogenesis (Lengeler, J. Mol. Microbiol. Biotechnol. 25 (2015) 79-93; Saier, J. Mol. Microbiol. Biotechnol. 25 (2015) 73-78). Membrane transporter protein families classified within the phosphotransfer-driven group translocators under the TCDB system as released on 17 Jun. 2019 include PTS systems linked to transport of glucose-glucosides, fructose-mannitol, lactose-N,N′-diacetylchitobiose-beta-glucoside, glucitol, galactitol, mannose-fructose-sorbose and ascorbate.

The major facilitator superfamily (MFS) is a superfamily of membrane transporter proteins catalyzing uniport, solute:cation (H+, but seldom Na+) symport and/or solute:H+ or solute:solute antiport. Most are of 400-600 amino acyl residues in length and possess either 12, 14, or occasionally, 24 transmembrane α-helical spanners (TMSs) as defined by the Transporter Classification Database operated by the Saier Lab Bioinformatics Group (www.tcdb.org).

“SET” or “Sugar Efflux Transporter” as used herein refers to membrane proteins of the SET family that are proteins with InterPRO domain IPRO04750 and/or are proteins that belong to the eggNOGv4.5 family ENOG410XTE9. Identification of the InterPro domain can be done by using the online tool on https://www.ebi.ac.uk/interpro/ or a standalone version of InterProScan (www.ebi.ac.uk/interpro/download.html) using the default values. Identification of the orthology family in eggNOGv4.5 can be done using the online version or a standalone version of eggNOG-mapperv1 (eggnogdb.embl.de/#/app/home).

The term “Siderophore” as used herein is referring to the secondary metabolite of various microorganisms that are mainly ferric ion specific chelators. These molecules have been classified as catecholate, hydroxamate, carboxylate and mixed types. Siderophores are in general synthesized by a nonribosomal peptide synthetase (NRPS) dependent pathway or an NRPS independent pathway (NIS). The most important precursor in NRPS-dependent siderophore biosynthetic pathway is chorismate. 2, 3-DHBA could be formed from chorismate by a three-step reaction catalyzed by isochorismate synthase, isochorismatase, and 2, 3-dihydroxybenzoate-2, 3-dehydrogenase. Siderophores can also be formed from salicylate that is formed from isochorismate by isochorismate pyruvate lyase. When ornithine is used as precursor for siderophores, biosynthesis depends on the hydroxylation of ornithine catalyzed by L-ornithine N5-monooxygenase. In the NIS pathway, an important step in siderophore biosynthesis is N(6)-hydroxylysine synthase.

A transporter is needed to export the siderophore outside the cell. Four superfamilies of membrane proteins are identified so far in this process: the major facilitator superfamily (MFS); the Multidrug/Oligosaccharidyl-lipid/Polysaccharide Flippase Superfamily (MOP); the resistance, nodulation and cell division superfamily (RND); and the ABC superfamily. In general, the genes involved in siderophore export are clustered together with the siderophore biosynthesis genes. The term “siderophore exporter” as used herein refers to such transporters needed to export the siderophore outside of the cell.

The ATP-binding cassette (ABC) superfamily contains both uptake and efflux transport systems, and the members of these two groups generally cluster loosely together. ATP hydrolysis without protein phosphorylation energizes transport. There are dozens of families within the ABC superfamily, and family generally correlates with substrate specificity. Members are classified according to class 3.A.1 as defined by the Transporter Classification Database operated by the Saier Lab Bioinformatics Group available via www.tcdb.org and providing a functional and phylogenetic classification of membrane transporter proteins.

The term “enabled efflux” means to introduce the activity of transport of a solute over the cytoplasm membrane and/or the cell wall. The transport may be enabled by introducing and/or increasing the expression of a transporter protein as described in this disclosure. The term “enhanced efflux” means to improve the activity of transport of a solute over the cytoplasm membrane and/or the cell wall. Transport of a solute over the cytoplasm membrane and/or cell wall may be enhanced by introducing and/or increasing the expression of a membrane transporter protein as described in this disclosure. “Expression” of a membrane transporter protein is defined as “overexpression” of the gene encoding the membrane transporter protein in the case the gene is an endogenous gene or “expression” in the case the gene encoding the membrane transporter protein is a heterologous gene that is not present in the wild type strain or cell.

The term “precursor” as used herein refers to substances that are taken up or synthetized by the cell for the specific production of an oligosaccharide according to this disclosure. In this sense a precursor can be an acceptor as defined herein, but can also be another substance, metabolite, which is first modified within the cell as part of the biochemical synthesis route of the oligosaccharide.

Examples of such precursors comprise the acceptors as defined herein, and/or glucose, galactose, fructose, glycerol, sialic acid, fucose, mannose, maltose, sucrose, lactose, dihydroxyacetone, glucosamine, N-acetyl-glucosamine, mannosamine, N-acetyl-mannosamine, galactosamine, N-acetylgalactosamine, phosphorylated sugars like e.g., but not limited to glucose-1-phosphate, galactose-1-phosphate, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-bisphosphate, mannose-6-phosphate, mannose-1-phosphate, glycerol-3-phosphate, glyceraldehyde-3-phosphate, dihydroxyacetone-phosphate, glucosamine-6-phosphate, N-acetyl-glucosamine-6-phosphate, N-acetylmannosamine-6-phosphate, N-acetylglucosamine-1-phosphate, N-acetyl-neuraminic acid-9-phosphate and/or nucleotide-activated sugars as defined herein like e.g., UDP-glucose, UDP-galactose, UDP-N-acetylglucosamine, CMP-sialic acid, GDP-mannose, GDP-4-dehydro-6-deoxy-α-D-mannose, GDP-fucose.

The term “acceptor” as used herein refers to a di- or an oligosaccharide that is taken up by the cell and modified by one or more glycosyltransferases with the addition of one or more monosaccharide units for oligosaccharide assembly. The acceptors are produced by methods comprising extraction from natural sources, biotechnological processes, physical processes, chemical processes, and combinations thereof. Examples of such acceptors comprise lactose, 2′FL, 3-FL, lacto-N-biose (LNB), lacto-N-triose, lacto-N-tetraose (LNT), lacto-N-neotetraose (LNnT), N-acetyl-lactosamine (LacNAc), lacto-N-pentaose (LNP), lacto-N-neopentaose, para lacto-N-pentaose, para lacto-N-neopentaose, lacto-N-novopentaose I, lacto-N-hexaose (LNH), lacto-N-neohexaose (LNnH), para lacto-N-neohexaose (pLNnH), para lacto-N-hexaose (pLNH), lacto-N-heptaose, lacto-N-neoheptaose, para lacto-N-neoheptaose, para lacto-N-heptaose, lacto-N-octaose (LNO), lacto-N-neooctaose, iso lacto-N-octaose, para lacto-N-octaose, iso lacto-N-neooctaose, novo lacto-N-neooctaose, para lacto-N-neooctaose, iso lacto-N-nonaose, novo lacto-N-nonaose, lacto-N-nonaose, lacto-N-decaose, iso lacto-N-decaose, novo lacto-N-decaose, lacto-N-neodecaose, galactosyllactose, a lactose extended with 1, 2, 3, 4, 5, or a multiple of N-acetyllactosamine units and/or 1, 2, 3, 4, 5, or a multiple of, Lacto-N-biose units, and oligosaccharide containing 1 or multiple N-acetyllactosamine units and or 1 or multiple lacto-N-biose units or an intermediate into oligosaccharide, fucosylated and sialylated versions thereof.

Throughout this disclosure, unless explicitly stated otherwise, the features “synthesize,” “synthesized” and “synthesis” are interchangeably used with the features “produce,” “produced” and “production,” respectively.

DETAILED DESCRIPTION

According to a first aspect, provided is a method for the production of a mixture comprising at least two oligosaccharides. The method comprises the steps of:

• • i. providing a cell, preferably a single cell, that is capable to express a glycosyltransferase and is capable to synthesize a nucleotide-sugar, wherein the nucleotide-sugar is donor for the glycosyltransferase, and
  • ii. cultivating the cell under conditions permissive to express the glycosyltransferase and to synthesize the nucleotide-sugar, and
  • iii. addition of at least two acceptors to the cultivation enabling the cell to produce at least two oligosaccharides, preferably any one of the acceptors is a di- or oligosaccharide,
  • iv. preferably, separating at least one of the oligosaccharides from the cultivation, more preferably separating all of the oligosaccharides from the cultivation.

In the scope of this disclosure, permissive conditions are understood to be conditions relating to physical or chemical parameters including but not limited to temperature, pH, pressure, osmotic pressure and product/precursor/acceptor concentration.

In a particular embodiment, the permissive conditions may include a temperature-range of 30+/−20 degrees centigrade, a pH-range of 7+/−3.

In a preferred embodiment of the method of this disclosure, the cultivation is fed with at least two, preferably at least three, more preferably at least four, even more preferably at least five, acceptors for the synthesis of any one of the oligosaccharides in the mixture. In a further preferred embodiment of the method, the cultivation is fed with at least two, preferably at least three, more preferably at least four, even more preferably at least five, acceptors for the synthesis of all of the oligosaccharides in the mixture. In a more preferred embodiment, the cultivation is fed with at least three acceptors for the synthesis of any one or all of the oligosaccharides in the mixture.

According to this disclosure, it is preferred that any one of the acceptors is a di- or oligosaccharide, more preferably each of the acceptors are di- or oligosaccharides, i.e., it is preferred that each acceptor is a disaccharide or an oligosaccharide. The skilled person will hence understand that it is preferred within the scope of this disclosure that the acceptors added in a method according to this disclosure can all be disaccharides, can all be oligosaccharides or can be a mixture of di- and oligosaccharides. A disaccharide acceptor is preferably chosen from a list comprising lactose (Gal-b1,4-Glc), lacto-N-biose (Gal-b1,3-GlcNAc), N-acetyllactosamine (Gal-b1,4-GlcNAc), LacDiNAc (GalNAc-b1,4-GlcNAc) and N-acetylgalactosaminylglucose (GalNAc-b1,4-Glc). An oligosaccharide acceptor is preferably a mammalian milk oligosaccharide (MMO), more preferably a human milk oligosaccharide (HMO), as defined herein. An oligosaccharide acceptor is preferably chosen from a list comprising 2′FL, 3-FL, lacto-N-triose, lacto-N-tetraose (LNT), lacto-N-neotetraose (LNnT), lacto-N-pentaose (LNP), lacto-N-neopentaose, para lacto-N-pentaose, para lacto-N-neopentaose, lacto-N-novopentaose I, lacto-N-hexaose (LNH), lacto-N-neohexaose (LNnH), para lacto-N-neohexaose (pLNnH), para lacto-N-hexaose (pLNH), lacto-N-heptaose, lacto-N-neoheptaose, para lacto-N-neoheptaose, para lacto-N-heptaose, lacto-N-octaose (LNO), lacto-N-neooctaose, iso lacto-N-octaose, para lacto-N-octaose, iso lacto-N-neooctaose, novo lacto-N-neooctaose, para lacto-N-neooctaose, iso lacto-N-nonaose, novo lacto-N-nonaose, lacto-N-nonaose, lacto-N-decaose, iso lacto-N-decaose, novo lacto-N-decaose, lacto-N-neodecaose, galactosyllactose, a lactose extended with 1, 2, 3, 4, 5, or a multiple of N-acetyllactosamine units and/or 1, 2, 3, 4, 5, or a multiple of, Lacto-N-biose units, and oligosaccharide containing 1 or multiple N-acetyllactosamine units and or 1 or multiple lacto-N-biose units or an intermediate into oligosaccharide, fucosylated and sialylated versions thereof.

In an optional embodiment of the method and/or cell according to this disclosure, the mixture according to this disclosure further comprises LacdiNAc (i.e., GalNAc-b1,4-GlCNAc) and/or GalNAc-b1,4-glucose.

In a preferred embodiment of the method according to this disclosure, one acceptor added to the cultivation has a degree of polymerization of two (DP3), preferably the acceptor is lactose, and the other acceptor(s) added to the cultivation have a degree of polymerization of at least three (DP3). The degree of polymerization (DP) of an acceptor refers to the number of monosaccharide units present in the acceptor structure. In another embodiment of the method according to this disclosure, any one of the acceptors added to the cultivation has a degree of polymerization of at least three (DP3), preferably all the acceptors have a degree of polymerization of at least three (DP3). In an alternative embodiment of the method according to this disclosure, any one of the acceptors added to the cultivation has a DP higher than three. An acceptor with a DP higher than three should be understood to comprise a tetrasaccharide built of 4 monosaccharide subunits (DP4), a pentasaccharide built of 5 monosaccharide subunits (DP5), an oligosaccharide structure built of DP6 or higher till DP20. In a preferred alternative embodiment, all of the acceptors added to the cultivation have a DP higher than three. For example, all acceptors added to the cultivation are tetrasaccharides and/or longer oligosaccharides built of 5, 6 or more monosaccharide subunits. In an alternative embodiment of the method according to this disclosure, any one of the acceptors added to the cultivation has a degree of polymerization of three (DP3). An acceptor with DP3 should be understood to be an oligosaccharide built of three monosaccharide subunits, also known as a trisaccharide. In a preferred embodiment of this disclosure, all of the acceptors have a DP3 structure. It is hence preferred that the cultivation is fed with an oligosaccharide mixture comprising at least two acceptors, wherein all acceptors are trisaccharides composed of three monosaccharide subunits. In an alternative embodiment of the method according to this disclosure, any one, preferably all, of the acceptors added to the cultivation has a DP higher than four, preferably higher than five.

In a preferred embodiment of the method according to this disclosure, all acceptors added to the cultivation have a different DP. For example, the cultivation can be fed with two acceptors wherein the first acceptor is a disaccharide and the second acceptor a trisaccharide. Alternatively, the cultivation can be fed with two acceptors wherein the first acceptor is a disaccharide and the second acceptor a tetrasaccharide or a longer saccharide of 5, 6 or more subunits. The cultivation can also be fed with two acceptors wherein the first acceptor is a trisaccharide and the second acceptor a tetrasaccharide or a longer saccharide of 5, 6 or more subunits. In a preferred embodiment, the cultivation is fed with more than two acceptors, wherein all the acceptors are built with a different number of monosaccharide subunits.

In another embodiment of this disclosure, the cultivation is fed with three or more acceptors for oligosaccharide synthesis, wherein the acceptors can have the same or a different DP relative to each other.

According to this disclosure, the method for the production of a mixture comprising at least two oligosaccharides can make use of a non-metabolically engineered cell or can make use of a metabolically engineered cell, i.e., a cell that is metabolically engineered for the production of the mixture comprising at least two oligosaccharides. Throughout this disclosure, unless explicitly stated otherwise, a “genetically modified cell” or “metabolically engineered cell” preferably means a cell that is genetically modified or metabolically engineered, respectively, for the production of the mixture comprising at least two oligosaccharides according to this disclosure. In the context of this disclosure, the at least two oligosaccharides of the mixture as disclosed herein preferably do not occur in the wild type progenitor of the metabolically engineered cell.

According to a preferred embodiment of the method according to this disclosure, the metabolically engineered cell used in the oligosaccharide synthesis is modified with gene expression modules wherein the expression from any one of the expression modules is constitutive or is created by a natural inducer.

The expression modules are also known as transcriptional units and comprise polynucleotides for expression of recombinant genes including coding gene sequences and appropriate transcriptional and/or translational control signals that are operably linked to the coding genes. The control signals comprise promoter sequences, untranslated regions, ribosome binding sites, terminator sequences. The expression modules can contain elements for expression of one single recombinant gene but can also contain elements for expression of more recombinant genes or can be organized in an operon structure for integrated expression of two or more recombinant genes. The polynucleotides may be produced by recombinant DNA technology using techniques well-known in the art. Methods that are well known to those skilled in the art to construct expression modules include, for example, in vitro recombinant DNA techniques, synthetic techniques, and in vivo genetic recombination. See, for example, the techniques described in Sambrook et al. (2001) Molecular Cloning: a laboratory manual, 3rd Edition, Cold Spring Harbor Laboratory Press, CSH, New York or to Current Protocols in Molecular Biology, John Wiley and Sons, N.Y. (1989 and yearly updates).

According to a preferred embodiment of this disclosure, the cell is modified with one or more expression modules. The expression modules can be integrated in the genome of the cell or can be presented to the cell on a vector. The vector can be present in the form of a plasmid, cosmid, phage, liposome, or virus, which is to be stably transformed/transfected into the metabolically engineered cell. Such vectors include, among others, chromosomal, episomal and virus-derived vectors, e.g., vectors derived from bacterial plasmids, from bacteriophage, from transposons, from yeast episomes, from insertion elements, from yeast chromosomal elements, from viruses, and vectors derived from combinations thereof, such as those derived from plasmid and bacteriophage genetic elements, such as cosmids and phagemids. These vectors may contain selection markers such as but not limited to antibiotic markers, auxotrophic markers, toxin-antitoxin markers, RNA sense/antisense markers. The expression system constructs may contain control regions that regulate as well as engender expression. Generally, any system or vector suitable to maintain, propagate or express polynucleotides and/or to express a polypeptide in a host may be used for expression in this regard. The appropriate DNA sequence may be inserted into the expression system by any of a variety of well-known and routine techniques, such as, for example, those set forth in Sambrook et al., see above. For recombinant production, cells can be genetically engineered to incorporate expression systems or portions thereof or polynucleotides of this disclosure. Introduction of a polynucleotide into the cell can be effected by methods described in many standard laboratory manuals, such as Davis et al., Basic Methods in Molecular Biology, (1986), and Sambrook et al., 1989, supra.

As used herein an expression module comprises polynucleotides for expression of at least one recombinant gene. The recombinant gene is involved in the expression of a polypeptide acting in the synthesis of the oligosaccharide mixture; or the recombinant gene is linked to other pathways in the host cell that are not involved in the synthesis of the mixture of three or more oligosaccharides. The recombinant genes encode endogenous proteins with a modified expression or activity, preferably the endogenous proteins are overexpressed; or the recombinant genes encode heterologous proteins that are heterogeneously introduced and expressed in the modified cell, preferably overexpressed. The endogenous proteins can have a modified expression in the cell that also expresses a heterologous protein.

According to a preferred embodiment of this disclosure, the expression of each of the expression modules is constitutive or created by a natural inducer. As used herein, constitutive expression should be understood as expression of a gene that is transcribed continuously in an organism. Expression that is created by a natural inducer should be understood as a facultative or regulatory expression of a gene that is only expressed upon a certain natural condition of the host (e.g., organism being in labor, or during lactation), as a response to an environmental change (e.g., including but not limited to hormone, heat, cold, light, oxidative or osmotic stress/signaling), or dependent on the position of the developmental stage or the cell cycle of the host cell including but not limited to apoptosis and autophagy.

According to a preferred embodiment of this disclosure, the cell preferably comprises multiple copies of the same coding DNA sequence encoding for one protein. In the context of this disclosure, the protein can be a glycosyltransferase, a membrane transporter protein or any other protein as disclosed herein. Throughout this disclosure, the feature “multiple” means at least 2, preferably at least 3, more preferably at least 4, even more preferably at least 5.

According to a preferred embodiment, this disclosure provides a method for the production of a mixture comprising at least two, preferably at least three, more preferably at least four, even more preferably at least five, even more preferably at least six, even more preferably at least seven, different oligosaccharides. The method comprises the steps as disclosed earlier herein. In this context, it is preferred to add multiple acceptors to the cultivation and/or providing a cell that is capable to express multiple glycosyltransferases, with each required nucleotide-sugar preferably being synthesized by the cell.

Preferably, the cell produces a mixture comprising three different oligosaccharides or more than three different oligosaccharides.

According to another preferred embodiment, the cell produces a mixture of different oligosaccharides comprising at least two oligosaccharides according to this disclosure differing in degree of polymerization.

According to a more preferred embodiment of the method according to this disclosure, at least one, preferably at least two, more preferably all, of the oligosaccharides in the mixture as produced according to this disclosure are MMOs, preferably HMOs, as defined herein. Throughout this disclosure, unless explicitly stated otherwise, the feature “mixture comprising at least two oligosaccharides” is preferably replaced with “mixture comprising at least two MMOs, preferably HMOs,” likewise it is preferred to replace “mixture comprising at least three oligosaccharides” with “mixture comprising at least three MMOs, preferably HMOs” etc.

In an embodiment of the method according to this disclosure, the glycosyltransferase is chosen from the list comprising fucosyltransferases, sialyltransferases, galactosyltransferases, glucosyltransferases, mannosyltransferases, N-acetylglucosaminyltransferases, N-acetylgalactosaminyltransferases, N-acetylmannosaminyltransferases, xylosyltransferases, glucuronyltransferases, galacturonyltransferases, glucosaminyltransferases, N-glycolylneuraminyltransferases, rhamnosyltransferases, N-acetylrhamnosyltransferases, UDP-4-amino-4,6-dideoxy-N-acetyl-beta-L-altrosamine transaminases, UDP-N-acetylglucosamine enolpyruvyl transferases and fucosaminyltransferases as defined herein.

In a preferred embodiment, the fucosyltransferase is chosen from the list comprising alpha-1,2-fucosyltransferase, alpha-1,3-fucosyltransferase, alpha-1,4-fucosyltransferase and alpha-1,6-fucosyltransferase. In another preferred embodiment, the sialyltransferase is chosen from the list comprising alpha-2,3-sialyltransferase, alpha-2,6-sialyltransferase and alpha-2,8-sialyltransferase. In another preferred embodiment, the galactosyltransferase is chosen from the list comprising beta-1,3-galactosyltransferase, N-acetylglucosamine beta-1,3-galactosyltransferase, beta-1,4-galactosyltransferase, N-acetylglucosamine beta-1,4-galactosyltransferase, alpha-1,3-galactosyltransferase and alpha-1,4-galactosyltransferase. In another preferred embodiment, the glucosyltransferase is chosen from the list comprising alpha-glucosyltransferase, beta-1,2-glucosyltransferase, beta-1,3-glucosyltransferase and beta-1,4-glucosyltransferase. In another preferred embodiment, the mannosyltransferase is chosen from the list comprising alpha-1,2-mannosyltransferase, alpha-1,3-mannosyltransferase and alpha-1,6-mannosyltransferase. In another preferred embodiment, the N-acetylglucosaminyltransferase is chosen from the list comprising galactoside beta-1,3-N-acetylglucosaminyltransferase and beta-1,6-N-acetylglucosaminyltransferase. In another preferred embodiment, the N-acetylgalactosaminyltransferase is an alpha-1,3-N-acetylgalactosaminyltransferase.

In a preferred embodiment, the cell expresses more than one glycosyltransferase as described herein. Preferably, the cell expresses at least two, more preferably at least three, even more preferably at least 4 glycosyltransferases, even more preferably at least 5 glycosyltransferases, even more preferably at least 6 glycosyltransferases as described herein.

In a further embodiment of the method of this disclosure, the cell is modified in the expression or activity of the glycosyltransferase. In a preferred embodiment, the glycosyltransferase is an endogenous protein of the cell with a modified expression or activity, preferably the endogenous glycosyltransferase is overexpressed; alternatively the glycosyltransferase is a heterologous protein that is heterogeneously introduced and expressed in the cell, preferably overexpressed. The endogenous glycosyltransferase can have a modified expression in the cell that also expresses a heterologous glycosyltransferase.

In another embodiment of the method of this disclosure, the glycosyltransferase is a fucosyltransferase and the cell is capable to synthesize GDP-Fuc. The GDP-fucose can be provided by an enzyme expressed in the cell or by the metabolism of the cell. Such cell producing GDP-fucose can express an enzyme converting, e.g., fucose, which is to be added to the cell, to GDP-fucose. This enzyme may be, e.g., a bifunctional fucose kinase/fucose-1-phosphate guanylyltransferase, like Fkp from Bacteroides fragilis, or the combination of one separate fucose kinase together with one separate fucose-1-phosphate guanylyltransferase like they are known from several species including Homo sapiens, Sus scrofa and Rattus norvegicus.

Preferably, the cell is modified to produce GDP-fucose. More preferably, the cell is modified for enhanced GDP-fucose production. The modification can be any one or more chosen from the group comprising knock-out of an UDP-glucose:undecaprenyl-phosphate glucose-1-phosphate transferase encoding gene, over-expression of a GDP-L-fucose synthase encoding gene, over-expression of a GDP-mannose 4,6-dehydratase encoding gene, over-expression of a mannose-1-phosphate guanylyltransferase encoding gene, over-expression of a phosphomannomutase encoding gene and over-expression of a mannose-6-phosphate isomerase encoding gene.

In another embodiment of the method of this disclosure, the glycosyltransferase is a sialyltransferase and the cell is capable to synthesize CMP-Neu5Ac. The CMP-Neu5Ac can be provided by an enzyme expressed in the cell or by the metabolism of the cell. Such cell producing CMP-Neu5Ac can express an enzyme converting, e.g., sialic acid, which is to be added to the cell, to CMP-Neu5Ac. This enzyme may be a CMP-sialic acid synthetase, like the N-acylneuraminate cytidylyltransferase from several species including Homo sapiens, Neisseria meningitidis, and Pasteurella multocida. Preferably, the cell is modified to produce CMP-Neu5Ac. More preferably, the cell is modified for enhanced CMP-Neu5Ac production. The modification can be any one or more chosen from the group comprising knock-out of an N-acetylglucosamine-6-phosphate deacetylase, knock-out of a glucosamine-6-phosphate deaminase, over-expression of a sialate synthase encoding gene, and over-expression of an N-acetyl-D-glucosamine-2-epimerase encoding gene.

In another embodiment of the method of this disclosure, the glycosyltransferase is an N-acetylglucosaminyltransferase and the cell is capable to synthesize UDP-GlcNAc. The UDP-GlcNAc can be provided by an enzyme expressed in the cell or by the metabolism of the cell. Such cell producing an UDP-GlcNAc can express enzymes converting, e.g., GlcNAc to UDP-GlcNAc. These enzymes may be an N-acetyl-D-glucosamine kinase, an N-acetylglucosamine-6-phosphate deacetylase, a phosphoglucosamine mutase, and an N-acetylglucosamine-1-phosphate uridyltransferase/glucosamine-1-phosphate acetyltransferase from several species including Homo sapiens, Escherichia coli. Preferably, the cell is modified to produce UDP-GlcNAc. More preferably, the cell is modified for enhanced UDP-GlcNAc production. The modification can be any one or more chosen from the group comprising knock-out of an N-acetylglucosamine-6-phosphate deacetylase, over-expression of an L-glutamine-D-fructose-6-phosphate aminotransferase, over-expression of a phosphoglucosamine mutase, and over-expression of an N-acetylglucosamine-1-phosphate uridyltransferase/glucosamine-1-phosphate acetyltransferase.

In another embodiment of the method of this disclosure, the glycosyltransferase is a galactosyltransferase and the cell is capable to synthesize UDP-Gal. The UDP-Gal can be provided by an enzyme expressed in the cell or by the metabolism of the cell. Such cell producing UDP-Gal can express an enzyme converting, e.g., UDP-glucose, to UDP-Gal. This enzyme may be, e.g., the UDP-glucose-4-epimerase GalE like as known from several species including Homo sapiens, Escherichia coli, and Rattus norvegicus. Preferably, the cell is modified to produce UDP-Gal. More preferably, the cell is modified for enhanced UDP-Gal production. The modification can be any one or more chosen from the group comprising knock-out of a bifunctional 5′-nucleotidase/UDP-sugar hydrolase encoding gene, knock-out of a galactose-1-phosphate uridylyltransferase encoding gene and over-expression of an UDP-glucose-4-epimerase encoding gene.

In another embodiment of the method of this disclosure, the glycosyltransferase is an N-acetylgalactosaminyltransferase and the cell is capable to synthesize UDP-GalNAc. The UDP-GalNAc can be provided by an enzyme expressed in the cell or by the metabolism of the cell. Such cell producing UDP-GalNAc can express an enzyme converting, e.g., UDP-GlcNAc to UDP-GalNAc. This enzyme may be, e.g., an UDP-N-acetylglucosamine 4-epimerase like e.g., wbgU from Plesiomonas shigelloides, gne from Yersinia enterocolitica or wbpP from Pseudomonas aeruginosa serotype O6. Preferably, the cell is modified to produce UDP-GalNAc. More preferably, the cell is modified for enhanced UDP-GalNAc production. The modification can be over-expression of an UDP-N-acetylglucosamine 4-epimerase.

In another embodiment of the method of this disclosure, the glycosyltransferase is an N-acetylmannosaminyltransferase and the cell is capable to synthesize UDP-ManNAc. The UDP-ManNAc can be provided by an enzyme expressed in the cell or by the metabolism of the cell. Such cell producing UDP-ManNAc can express an enzyme converting, e.g., UDP-GlcNAc to UDP-ManNAc. This enzyme may be, e.g., UDP-GlcNAc 2-epimerase like e.g., cap5P from Staphylococcus aureus, RffE from E. coli, Cps19fK from S. pneumoniae, or RfbC from S. enterica. Preferably, the cell is modified to produce UDP-ManNAc. More preferably, the cell is modified for enhanced UDP-ManNAc production. The modification can be over-expression of an UDP-GlcNAc 2-epimerase.

In another embodiment of the method of this disclosure, the cell is capable to synthesize any one of the nucleotide-sugars chosen from the list comprising GDP-Fuc, CMP-Neu5Ac, UDP-GlcNAc, UDP-Gal, UDP-N-acetylgalactosamine (UDP-GalNAc), UDP-N-acetylmannosamine (UDP-ManNAc), GDP-mannose (GDP-Man), UDP-glucose (UDP-Glc), UDP-2-acetamido-2,6-dideoxy-L-arabino-4-hexulose, UDP-2-acetamido-2,6-dideoxy-L-lyxo-4-hexulose, UDP-N-acetyl-L-rhamnosamine (UDP-L-RhaNAc or UDP-2-acetamido-2,6-dideoxy-L-mannose), dTDP-N-acetylfucosamine, UDP-N-acetylfucosamine (UDP-L-FucNAc or UDP-2-acetamido-2,6-dideoxy-L-galactose), UDP-N-acetyl-L-pneumosamine (UDP-L-PneNAC or UDP-2-acetamido-2,6-dideoxy-L-talose), UDP-N-acetylmuramic acid, UDP-N-acetyl-L-quinovosamine (UDP-L-QuiNAc or UDP-2-acetamido-2,6-dideoxy-L-glucose), GDP-L-quinovose, CMP-N-glycolylneuraminic acid (CMP-Neu5Gc), CMP-Neu4Ac, CMP-Neu5Ac9N₃, CMP-Neu4,5Ac₂, CMP-Neu5,7Ac₂, CMP-Neu5,9Ac₂, CMP-Neu5,7(8,9)Ac₂, UDP-glucuronate, UDP-galacturonate, GDP-rhamnose, UDP-xylose. In a preferred embodiment, the cell is metabolically engineered for the production of a nucleotide-sugar. In another preferred embodiment, the cell is modified and/or engineered for the optimized production of a nucleotide-sugar.

According to the method of this disclosure, at least one of the oligosaccharides of the mixture is fucosylated, sialylated, galactosylated, glucosylated, xylosylated, mannosylated, contains an N-acetylglucosamine, contains an N-acetylneuraminate, contains an N-glycolylneuraminate, contains an N-acetylgalactosamine, contains a rhamnose, contains a glucuronate, contains a galacturonate, and/or contains an N-acetylmannosamine.

In a preferred embodiment, the oligosaccharide mixture comprises charged oligosaccharides. More preferably, at least one of the charged oligosaccharides is a sialylated oligosaccharide. Alternatively, and or additionally, the oligosaccharide mixture comprises neutral oligosaccharides.

In another preferred embodiment, the oligosaccharide mixture comprises fucosylated neutral oligosaccharides. Alternatively, and or additionally, the oligosaccharide mixture comprises non-fucosylated neutral oligosaccharides.

Preferably, the oligosaccharide mixture comprises at least one fucosylated oligosaccharide as defined herein.

Alternatively or additionally, the oligosaccharide mixture comprises at least one sialylated oligosaccharide as defined herein.

Alternatively or additionally, the mixture of oligosaccharides comprises at least one oligosaccharide of 3 or more monosaccharide subunits linked to each other via glycosidic bonds, wherein at least one of the monosaccharide residues is a GlcNAc residue. The oligosaccharide can contain more than one GlcNAc residue, e.g., two, three or more. The oligosaccharide can be a neutral oligosaccharide or a charged oligosaccharide, e.g., also comprising sialic acid structures. GlcNAc can be present at the reducing end of the oligosaccharide. The GlcNAc can also be present at the non-reducing end of the oligosaccharide. The GlcNAc can also be present within the oligosaccharide structure. GlcNAc can be linked to other monosaccharide subunits comprising galactose, fucose, Neu5Ac, Neu5Gc.

Alternatively or additionally, the oligosaccharide mixture comprises at least one galactosylated oligosaccharide and contains at least one galactose monosaccharide subunit. The galactosylated oligosaccharide is a saccharide structure comprising at least three monosaccharide subunits linked to each other via glycosidic bonds, wherein at least one of the monosaccharide subunit is a galactose. The galactosylated oligosaccharide can contain more than one galactose residue, e.g., two, three or more. The galactosylated oligosaccharide can be a neutral oligosaccharide or a charged oligosaccharide, e.g., also comprising sialic acid structures. Galactose can be linked to other monosaccharide subunits comprising glucose, GlcNAc, fucose, sialic acid.

Preferably, all oligosaccharides present in the oligosaccharide mixture are fucosylated oligosaccharides. More preferably, the oligosaccharide mixture comprises three fucosylated oligosaccharides as defined herein.

According to a preferred embodiment, this disclosure provides a method for the production of a mixture comprising at least two, preferably at least three, more preferably at least four, even more preferably at least five, even more preferably at least six, even more preferably at least seven, different (i) oligosaccharides, wherein the mixture is composed of charged, preferably sialylated, and neutral oligosaccharides (preferably neutral fucosylated, or preferably neutral non-fucosylated); (ii) neutral fucosylated oligosaccharides; (iii) sialylated oligosaccharides; and/or (iv) neutral non-fucosylated oligosaccharides. The method comprises the steps as disclosed earlier herein. In this context, it is preferred to add at least two, more preferably at least three acceptors to the cultivation and/or providing a cell that is capable to express multiple glycosyltransferases with each required nucleotide-sugar preferably being synthesized by the cell.

In this regard, for production of a mixture according to (i) above, it is preferred to provide a cell, preferably a single cell, which is capable of expressing a sialyltransferase and at least one additional glycosyltransferase as described herein, synthesizing the nucleotide-sugar CMP-N-acetylneuraminic acid (CMP-Neu5Ac) and one or more nucleotide-sugar(s) as described herein that is/are donor(s) for the additional glycosyltransferase(s) and preferably wherein at least three, more preferably at least four, even more preferably at least five, acceptors are added to the cultivation for the synthesis of any one of the oligosaccharides in the mixture, preferably for the synthesis of all of the oligosaccharides in the mixture.

In this regard, for production of a mixture according to (ii) above, it is preferred to provide a cell, preferably a single cell, that is capable of expressing a fucosyltransferase and at least one additional glycosyltransferase as described herein, synthesizing the nucleotide-sugar GDP-fucose (GDP-Fuc) and one or more nucleotide-sugar(s) as described herein that is/are donor(s) for the additional glycosyltransferase(s) and preferably wherein at least three, more preferably at least four, even more preferably at least five, acceptors are added to the cultivation for the synthesis of any one of the oligosaccharides in the mixture, preferably for the synthesis of all of the oligosaccharides in the mixture.

In this regard, for production of a mixture according to (iii) above, it is preferred to provide a cell, preferably a single cell, that is capable of expressing a sialyltransferase and at least one additional glycosyltransferase as described herein, synthesizing the nucleotide-sugar CMP-N-acetylneuraminic acid (CMP-Neu5Ac) and one or more nucleotide-sugar(s) as described herein that is/are donor(s) for the additional glycosyltransferase(s) and preferably wherein at least three, more preferably at least four, even more preferably at least five, acceptors are added to the cultivation for the synthesis of any one of the oligosaccharides in the mixture, preferably for the synthesis of all of the oligosaccharides in the mixture.

In this regard, for production of a mixture according to (iv) above, it is preferred to provide a cell, preferably a single cell, that is capable of expressing at least two glycosyltransferases as described herein, synthesizing one or more nucleotide-sugar(s) as described herein that is/are donor(s) for the additional glycosyltransferase(s) and preferably wherein at least three, more preferably at least four, even more preferably at least five, acceptors are added to the cultivation for the synthesis of any one of the oligosaccharides in the mixture, preferably for the synthesis of all of the oligosaccharides in the mixture.

In the context of this disclosure, it should be understood that the mixture comprising at least two oligosaccharides according to this disclosure is preferably synthesized intracellularly. The skilled person will further understand that a fraction or substantially all of the synthesized oligosaccharides remains intracellularly and/or is excreted outside the cell either via passive or via active transport.

In a preferred embodiment of the method of this disclosure, any one of the oligosaccharides, more preferably all of the oligosaccharides, is/are translocated to the outside of the cell by a passive transport i.e., without means of an active transport system consuming energy from the cell.

In another preferred embodiment of the method of this disclosure, the cell is further metabolically engineered for:

• • i) modified expression of an endogenous membrane protein, and/or
  • ii) modified activity of an endogenous membrane protein, and/or
  • iii) expression of a homologous membrane protein, and/or
  • iv) expression of a heterologous membrane protein,

wherein the membrane protein is involved in the secretion of any one of the oligosaccharides outside the cell. The cell can express one of the membrane proteins that is involved in the secretion of any one of the oligosaccharides from the cell to the outside of the cell. The cell can also express more than one of the membrane proteins. Any one of the membrane proteins can translocate one or more of the oligosaccharides to the outside of the cell. The cell producing a mixture of at least two, preferably at least three, oligosaccharides can translocate any one of the oligosaccharides comprising passive diffusion, channel membrane proteins, membrane transporter proteins, membrane carrier proteins.

In one embodiment, the cell is further metabolically engineered for:

• • i. modified expression of an endogenous membrane protein, and/or
  • ii. modified activity of an endogenous membrane protein, and/or
  • iii. expression of a homologous membrane protein, and/or
  • iv. expression of a heterologous membrane protein,

wherein the membrane protein is involved in the uptake of a precursor for the synthesis of any one of the oligosaccharides of the mixture, preferably wherein the membrane protein is involved in the uptake of all of the required precursors, more preferably wherein the membrane protein is involved in the uptake of all of the acceptors.

In another preferred embodiment of the method of this disclosure, the cell is further metabolically engineered for:

• • i) modified expression of an endogenous membrane protein, and/or
  • ii) modified activity of an endogenous membrane protein, and/or
  • iii) expression of a homologous membrane protein, and/or
  • iv) expression of a heterologous membrane protein,

wherein the membrane protein is involved in the uptake of an acceptor for the synthesis of any one of the oligosaccharides. The term “acceptor” should be understood as explained in the definitions as disclosed herein. The cell can express one of the membrane proteins that is involved in the uptake of any type of acceptor used in the synthesis of any one of the oligosaccharides. The cell can also express more than one of the membrane proteins, involved in the uptake of at least one of the acceptors. The cell can be modified for the uptake of more than one acceptor for the synthesis of any one of the oligosaccharides.

In a more preferred embodiment of the method of this disclosure, the membrane protein is chosen from the list comprising porters, P-P-bond-hydrolysis-driven transporters, β-barrel porins, auxiliary transport proteins, putative transport proteins and phosphotransfer-driven group translocators. In an even more preferred embodiment of the method of this disclosure, the porters comprise MFS transporters, sugar efflux transporters and siderophore exporters. In another more preferred embodiment of the method of this disclosure, the P-P-bond-hydrolysis-driven transporters comprise ABC transporters and siderophore exporters.

In another preferred embodiment of the method of this disclosure, the membrane protein provides improved production of the mixture of at least two oligosaccharides. In an alternative and/or additional preferred embodiment of the method of this disclosure, the membrane protein provides enabled efflux of the mixture of at least two oligosaccharides.

In a more preferred embodiment of the method of this disclosure, the cell expresses a membrane protein belonging to the family of MFS transporters like e.g., an MdfA polypeptide of the multidrug transporter MdfA family from species comprising E. coli (UniProt ID POAEY8), Cronobacter muytjensii (UniProt ID AOA2T7ANQ9), Citrobacter youngae (UniProt ID D4BC23) and Yokenella regensburgei (UniProt ID G9Z5F4). In another more preferred embodiment of the method of this disclosure, the cell expresses a membrane protein belonging to the family of sugar efflux transporters like e.g., a SetA polypeptide of the SetA family from species comprising E. coli (UniProt ID P31675), Citrobacter koseri (UniProt ID A0A078LM16) and Klebsiella pneumoniae (UniProt ID A0A0C4MGS7). In another more preferred embodiment of the method of this disclosure, the cell expresses a membrane protein belonging to the family of siderophore exporters like e.g., the E. coli entS (UniProt ID P24077) and the E. coli iceT (UniProt ID A0A024L207). In another more preferred embodiment of the method of this disclosure, the cell expresses a membrane protein belonging to the family of ABC transporters like e.g., oppF from E. coli (UniProt ID P77737), lmrA from Lactococcus lactis subsp. lactis bv. diacetylactis (UniProt ID AOA1VONEL4) and Blon 2475 from Bifidobacterium longum subsp. infantis (UniProt ID B7GPD4).

Optionally, the cell is transformed to comprise at least one nucleic acid sequence encoding a protein selected from the group comprising lactose transporter, N-acetylneuraminic acid transporter, fucose transporter, transporter for a nucleotide-activated sugar wherein the transporter internalizes a to the medium added precursor or acceptor for oligosaccharide synthesis.

In a preferred embodiment of the method according to this disclosure, the cell resists the phenomenon of lactose killing when grown in an environment in which lactose is combined with one or more other carbon source(s). With the term “lactose killing” is meant the hampered growth of the cell in medium in which lactose is present together with another carbon source. In a preferred embodiment, the cell is genetically modified such that it retains at least 50% of the lactose influx without undergoing lactose killing, even at high lactose concentrations, as is described in WO 2016/075243. The genetic modification comprises expression and/or over-expression of an exogenous and/or an endogenous lactose transporter gene by a heterologous promoter that does not lead to a lactose killing phenotype and/or modification of the codon usage of the lactose transporter to create an altered expression of the lactose transporter that does not lead to a lactose killing phenotype. The content of WO 2016/075243 in this regard is incorporated by reference.

In another embodiment of this disclosure, the acceptors are produced by methods comprising extraction from natural sources, biotechnological processes including synthesis by the cell producing an oligosaccharide mixture according to this disclosure or another cell that does not produce the oligosaccharide mixture according to this disclosure, physical processes, chemical processes, and combinations thereof.

In another preferred embodiment of the method, the cell is producing an acceptor for the synthesis of any one of the oligosaccharides. In a more preferred embodiment, the cell is producing one or more acceptors for the synthesis of the oligosaccharide mixture, more preferably the cell is producing all acceptors for the synthesis of the oligosaccharide mixture according to this disclosure. In an even more preferred embodiment, the cell is modified for optimized production of any one of the acceptors for the synthesis of any one of the oligosaccharides, more preferably the cell is modified for optimized production of all of the acceptors for the synthesis of the oligosaccharide mixture according to this disclosure.

In another preferred embodiment of the method, the acceptors that are added to the cultivation are not produced by the cell provided in the method according to this disclosure.

In a preferred embodiment of the method of this disclosure, the cell confers enhanced bacteriophage resistance. The enhancement of bacteriophage resistance can be derived from reduced expression of an endogenous membrane protein and/or mutation of an endogenous membrane protein encoding gene. The term “phage insensitive” or “phage resistant” or “phage resistance” or “phage resistant profile” is understood to mean a bacterial strain that is less sensitive, and preferably insensitive to infection and/or killing by phage and/or growth inhibition. As used herein, the terms “anti-phage activity” or “resistant to infection by at least one phage” refers to an increase in resistance of a bacterial cell expressing a functional phage resistance system to infection by at least one phage family in comparison to a bacterial cell of the same species under the same developmental stage (e.g., culture state) that does not express a functional phage resistance system, as may be determined by e.g., bacterial viability, phage lysogeny, phage genomic replication and phage genomic degradation. The phage can be a lytic phage or a temperate (lysogenic) phage. Membrane proteins involved in bacteriophage resistance of a cell comprise OmpA, OmpC, OmpF, OmpT, BtuB, TolC, LamB, FhuA, TonB, FadL, Tsx, FepA, YncD, PhoE, and NfrA and homologs thereof.

In a preferred embodiment of the method of this disclosure, the cell confers reduced viscosity. Reduced viscosity of a cell can be obtained by a modified cell wall biosynthesis. Cell wall biosynthesis can be modified comprising reduced or abolished synthesis of, for example, poly-N-acetyl-glucosamine, the enterobacterial common antigen, cellulose, colanic acid, core oligosaccharides, osmoregulated periplasmic glucans and glucosylglycerol, glycan, and trehalose.

According to another embodiment of the method of this disclosure, the cell is capable to produce phosphoenolpyruvate (PEP). In a preferred embodiment of the method of this disclosure, the cell is modified for enhanced production and/or supply of PEP compared to a non-modified progenitor.

In a preferred embodiment and as a means for enhanced production and/or supply of PEP, one or more PEP-dependent, sugar-transporting phosphotransferase system(s) is/are disrupted such as but not limited to: 1) the N-acetyl-D-glucosamine Npi-phosphotransferase (EC 2.7.1.193), which is encoded, for instance, by the nagE gene (or the cluster nagABCD) in E. coli or Bacillus species, 2) ManXYZ that encodes the Enzyme 11 Man complex (mannose PTS permease, protein-Npi-phosphohistidine-D-mannose phosphotransferase) that imports exogenous hexoses (mannose, glucose, glucosamine, fructose, 2-deoxyglucose, mannosamine, N-acetylglucosamine, etc.) and releases the phosphate esters into the cell cytoplasm, 3) the glucose-specific PTS transporter (for instance, encoded by PtsG/Crr) that takes up glucose and forms glucose-6-phosphate in the cytoplasm, 4) the sucrose-specific PTS transporter that takes up sucrose and forms sucrose-6-phosphate in the cytoplasm, 5) the fructose-specific PTS transporter (for instance, encoded by the genes fruA and fruB and the kinase fruK that takes up fructose and forms in a first step fructose-1-phosphate and in a second step fructose1,6 bisphosphate, 6) the lactose PTS transporter (for instance, encoded by lacE in Lactococcus casei) that takes up lactose and forms lactose-6-phosphate, 7) the galactitol-specific PTS enzyme that takes up galactitol and/or sorbitol and forms galactitol-1-phosphate or sorbitol-6-phosphate, respectively, 8) the mannitol-specific PTS enzyme that takes up mannitol and/or sorbitol and forms mannitol-1-phosphate or sorbitol-6-phosphate, respectively, and 9) the trehalose-specific PTS enzyme that takes up trehalose and forms trehalose-6-phosphate.

In another and/or additional preferred embodiment and as a means for enhanced production and/or supply of PEP, the full PTS system is disrupted by disrupting the PtsIH/Crr gene cluster. PtsI (Enzyme I) is a cytoplasmic protein that serves as the gateway for the phosphoenolpyruvate:sugar phosphotransferase system (PTSsugar) of E. coli K-12. PtsI is one of two (PtsI and PtsH) sugar non-specific protein constituents of the PTSsugar that along with a sugar-specific inner membrane permease effects a phosphotransfer cascade that results in the coupled phosphorylation and transport of a variety of carbohydrate substrates. HPr (histidine containing protein) is one of two sugar-non-specific protein constituents of the PTSsugar. It accepts a phosphoryl group from phosphorylated Enzyme I (PtsI-P) and then transfers it to the EIIA domain of any one of the many sugar-specific enzymes (collectively known as Enzymes II) of the PTSsugar. Crr or EIIAGlc is phosphorylated by PEP in a reaction requiring PtsH and PtsI.

In another and/or additional preferred embodiment, the cell is further modified to compensate for the deletion of a PTS system of a carbon source by the introduction and/or overexpression of the corresponding permease. These are e.g., permeases or ABC transporters that comprise but are not limited to transporters that specifically import lactose such as e.g., the transporter encoded by the LacY gene from E. coli, sucrose such as e.g., the transporter encoded by the cscB gene from E. coli, glucose such as e.g., the transporter encoded by the galP gene from E. coli, fructose such as e.g., the transporter encoded by the fruI gene from Streptococcus mutans, or the Sorbitol/mannitol ABC transporter such as the transporter encoded by the cluster SmoEFGK of Rhodobacter sphaeroides, the trehalose/sucrose/maltose transporter such as the transporter encoded by the gene cluster ThuEFGK of Sinorhizobium meliloti and the N-acetylglucosamine/galactose/glucose transporter such as the transporter encoded by NagP of Shewanella oneidensis. Examples of combinations of PTS deletions with overexpression of alternative transporters are: 1) the deletion of the glucose PTS system, e.g., ptsG gene, combined with the introduction and/or overexpression of a glucose permease (e.g., galP of glcP), 2) the deletion of the fructose PTS system, e.g., one or more of the fruB, fruA, fruK genes, combined with the introduction and/or overexpression of fructose permease, e.g., fruI, 3) the deletion of the lactose PTS system, combined with the introduction and/or overexpression of lactose permease, e.g., LacY, and/or 4) the deletion of the sucrose PTS system, combined with the introduction and/or overexpression of a sucrose permease, e.g., cscB.

In a further preferred embodiment, the cell is modified to compensate for the deletion of a PTS system of a carbon source by the introduction of carbohydrate kinases, such as glucokinase (EC 2.7.1.1, EC 2.7.1.2, EC 2.7.1.63), galactokinase (EC 2.7.1.6), and/or fructokinase (EC 2.7.1.3, EC 2.7.1.4). Examples of combinations of PTS deletions with overexpression of alternative transporters and a kinase are: 1) the deletion of the glucose PTS system, e.g., ptsG gene, combined with the introduction and/or overexpression of a glucose permease (e.g., galP of glcP), combined with the introduction and/or overexpression of a glucokinase (e.g., glk), and/or 2) the deletion of the fructose PTS system, e.g., one or more of the fruB, fruA, fruK genes, combined with the introduction and/or overexpression of fructose permease, e.g., fruI, combined with the introduction and/or overexpression of a fructokinase (e.g., frk or mak).

In another and/or additional preferred embodiment and as a means for enhanced production and/or supply of PEP, the cell is modified by the introduction of or modification in any one or more of the list comprising phosphoenolpyruvate synthase activity (EC: 2.7.9.2 encoded, for instance, in E. coli by ppsA), phosphoenolpyruvate carboxykinase activity (EC 4.1.1.32 or EC 4.1.1.49 encoded, for instance, in Corynebacterium glutamicum by PCK or in E. coli by pckA, resp.), phosphoenolpyruvate carboxylase activity (EC 4.1.1.31 encoded, for instance, in E. coli by ppc), oxaloacetate decarboxylase activity (EC 4.1.1.112 encoded, for instance, in E. coli by eda), pyruvate kinase activity (EC 2.7.1.40 encoded, for instance, in E. coli by pykA and pykF), pyruvate carboxylase activity (EC 6.4.1.1 encoded, for instance, in B. subtilis by pyc) and malate dehydrogenase activity (EC 1.1.1.38 or EC 1.1.1.40 encoded, for instance, in E. coli by maeA or maeB, resp.).

In a more preferred embodiment, the cell is modified to overexpress any one or more of the polypeptides comprising ppsA from E. coli (UniProt ID P23538), PCK from C. glutamicum (UniProt ID Q6F5A5), pcka from E. coli (UniProt ID P22259), eda from E. coli (UniProt ID P0A955), maeA from E. coli (UniProt ID P26616) and maeB from E. coli (UniProt ID P76558).

In another and/or additional preferred embodiment, the cell is modified to express any one or more polypeptide having phosphoenolpyruvate synthase activity, phosphoenolpyruvate carboxykinase activity, oxaloacetate decarboxylase activity, or malate dehydrogenase activity.

In another and/or additional preferred embodiment and as a means for enhanced production and/or supply of PEP, the cell is modified by a reduced activity of phosphoenolpyruvate carboxylase activity, and/or pyruvate kinase activity, preferably a deletion of the genes encoding for phosphoenolpyruvate carboxylase, the pyruvate carboxylase activity and/or pyruvate kinase.

In an exemplary embodiment, the cell is genetically modified by different adaptations such as the overexpression of phosphoenolpyruvate synthase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate synthase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the deletion of a pyruvate carboxylase gene, the overexpression of phosphoenolpyruvate carboxykinase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate carboxykinase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate carboxykinase combined with the deletion of a pyruvate carboxylase gene, the overexpression of oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene, the overexpression of oxaloacetate decarboxylase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of oxaloacetate decarboxylase combined with the deletion of a pyruvate carboxylase gene, the overexpression of malate dehydrogenase combined with the deletion of a pyruvate kinase gene, the overexpression of malate dehydrogenase combined with the deletion of a phosphoenolpyruvate carboxylase gene and/or the overexpression of malate dehydrogenase combined with the deletion of a pyruvate carboxylase gene.

In another exemplary embodiment, the cell is genetically modified by different adaptations such as the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a malate dehydrogenase, the overexpression of phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase, the overexpression of phosphoenolpyruvate carboxykinase combined with the overexpression of a malate dehydrogenase, the overexpression of oxaloacetate decarboxylase combined with the overexpression of a malate dehydrogenase, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of a malate dehydrogenase, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase, the overexpression of phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase and/or the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase.

In another exemplary embodiment, the cell is genetically modified by different adaptations such as the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate carboxykinase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene, the overexpression of an oxaloacetate decarboxylase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene, the overexpression of phosphoenolpyruvate synthase combined the overexpression of oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene.

In another exemplary embodiment, the cell is genetically modified by different adaptations such as the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a malate dehydrogenase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of a malate dehydrogenase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of an oxaloacetate decarboxylase combined with the overexpression of a malate dehydrogenase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of a malate dehydrogenase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a phosphoenolpyruvate carboxylase gene.

In another exemplary embodiment, the cell is genetically modified by different adaptations such as the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase combined with the deletion of a pyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate carboxylase gene, the overexpression of an oxaloacetate decarboxylase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate carboxylase gene.

In another exemplary embodiment, the cell is genetically modified by different adaptations such as the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of an oxaloacetate decarboxylase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a phosphoenolpyruvate carboxylase gene.

In another exemplary embodiment, the cell is genetically modified by different adaptations such as the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of an oxaloacetate decarboxylase combined with the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of a phosphoenolpyruvate carboxykinase and the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of a phosphoenolpyruvate carboxykinase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene, the overexpression of phosphoenolpyruvate synthase combined with the overexpression of an oxaloacetate decarboxylase and the overexpression of a malate dehydrogenase combined with the deletion of a pyruvate kinase gene and a pyruvate carboxylase gene and a phosphoenolpyruvate carboxylase gene.

According to another preferred embodiment of the method of this disclosure, the cell comprises a modification for reduced production of acetate compared to a non-modified progenitor. The modification can be any one or more chosen from the group comprising overexpression of an acetyl-coenzyme A synthetase, a full or partial knock-out or rendered less functional pyruvate dehydrogenase and a full or partial knock-out or rendered less functional lactate dehydrogenase.

In a further embodiment of the method of this disclosure, the cell is modified in the expression or activity of at least one acetyl-coenzyme A synthetase like e.g., acs from E. coli, S. cerevisiae, H. sapiens, M. musculus. In a preferred embodiment, the acetyl-coenzyme A synthetase is an endogenous protein of the cell with a modified expression or activity, preferably the endogenous acetyl-coenzyme A synthetase is overexpressed; alternatively, the acetyl-coenzyme A synthetase is a heterologous protein that is heterogeneously introduced and expressed in the cell, preferably overexpressed. The endogenous acetyl-coenzyme A synthetase can have a modified expression in the cell that also expresses a heterologous acetyl-coenzyme A synthetase. In a more preferred embodiment, the cell is modified in the expression or activity of the acetyl-coenzyme A synthetase acs from E. coli (UniProt ID P27550). In another and/or additional preferred embodiment, the cell is modified in the expression or activity of a functional homolog, variant or derivative of acs from E. coli (UniProt ID P27550) having at least 80% overall sequence identity to the full-length of the polypeptide from E. coli (UniProt ID P27550) and having acetyl-coenzyme A synthetase activity.

In an alternative and/or additional further embodiment of the method of this disclosure, the cell is modified in the expression or activity of at least one pyruvate dehydrogenase like e.g., from E. coli, S. cerevisiae, H. sapiens and R. norvegicus. In a preferred embodiment, the cell has been modified to have at least one partially or fully knocked out or mutated pyruvate dehydrogenase encoding gene by means generally known by the person skilled in the art resulting in at least one protein with less functional or being disabled for pyruvate dehydrogenase activity. In a more preferred embodiment, the cell has a full knock-out in the poxB encoding gene resulting in a cell lacking pyruvate dehydrogenase activity.

In an alternative and/or additional further embodiment of the method of this disclosure, the cell is modified in the expression or activity of at least one lactate dehydrogenase like e.g., from E. coli, S. cerevisiae, H. sapiens and R. norvegicus. In a preferred embodiment, the cell has been modified to have at least one partially or fully knocked out or mutated lactate dehydrogenase encoding gene by means generally known by the person skilled in the art resulting in at least one protein with less functional or being disabled for lactate dehydrogenase activity. In a more preferred embodiment, the cell has a full knock-out in the ldhA encoding gene resulting in a cell lacking lactate dehydrogenase activity.

According to another preferred embodiment of the method of this disclosure, the cell comprises a lower or reduced expression and/or abolished, impaired, reduced or delayed activity of any one or more of the proteins comprising beta-galactosidase, galactoside 0-acetyltransferase, N-acetylglucosamine-6-phosphate deacetylase, glucosamine-6-phosphate deaminase, N-acetylglucosamine repressor, ribonucleotide monophosphatase, EIICBA-Nag, UDP-glucose:undecaprenyl-phosphate glucose-1-phosphate transferase, L-fuculokinase, L-fucose isomerase, N-acetylneuraminate lyase, N-acetylmannosamine kinase, N-acetylmannosamine-6-phosphate 2-epimerase, EIIAB-Man, EIIC-Man, EIID-Man, ushA, galactose-1-phosphate uridylyltransferase, glucose-1-phosphate adenylyltransferase, glucose-1-phosphatase, ATP-dependent 6-phosphofructokinase isozyme 1, ATP-dependent 6-phosphofructokinase isozyme 2, glucose-6-phosphate isomerase, aerobic respiration control protein, transcriptional repressor IclR, lon protease, glucose-specific translocating phosphotransferase enzyme IIBC component ptsG, glucose-specific translocating phosphotransferase (PTS) enzyme IIBC component malX, enzyme IIAGlc, beta-glucoside specific PTS enzyme II, fructose-specific PTS multiphosphoryl transfer protein FruA and FruB, ethanol dehydrogenase aldehyde dehydrogenase, pyruvate-formate lyase, acetate kinase, phosphoacyltransferase, phosphate acetyltransferase, pyruvate decarboxylase compared to a non-modified progenitor.

According to another preferred embodiment of the method of this disclosure, the cell comprises a catabolic pathway for selected mono-, di- or oligosaccharides that is at least partially inactivated, the mono-, di-, or oligosaccharides being involved in and/or required for the production of the mixture of at least two oligosaccharides.

In another embodiment of the method of this disclosure, at least one of the oligosaccharides in the mixture produced by the cell is a mammalian milk oligosaccharide. The cell can produce one mammalian milk oligosaccharide in the produced mixture of at least two oligosaccharides. The cell can produce more than one mammalian milk oligosaccharide in the produced mixture of at least two oligosaccharides. In a preferred embodiment, all the oligosaccharides in the produced mixture of at least two oligosaccharides are mammalian milk oligosaccharides. Throughout this disclosure, unless explicitly stated otherwise, the feature “oligosaccharide” or “oligosaccharides” is preferably replaced with “mammalian milk oligosaccharide (MMO), preferably human milk oligosaccharide (HMO)” or “mammalian milk oligosaccharides (MMOs), preferably human milk oligosaccharides (HMOs),” respectively.

As such, a preferred method according to this disclosure is a method for the production of a mixture comprising at least two MMOs, preferably HMOs, the method comprises the steps as described herein. Preferably, the mixture comprising at least three, more preferably at least four, even more preferably at least five, even more preferably at least six, even more preferably at least seven, different MMOs (preferably HMOs).

In another embodiment of the method of this disclosure, any one of the oligosaccharides produced by the cell is an antigen of the human ABO blood group system. In a more preferred embodiment, all the oligosaccharides produced by the cell are antigens of the human ABO blood group system. As such, a preferred method according to this disclosure is a method for the production of a mixture comprising at least two antigens of the human ABO blood group system, the method comprises the steps as described herein. Preferably, the mixture comprising at least three different antigens of the human ABO blood group system.

Another embodiment of this disclosure provides for a method and a cell wherein a mixture comprising at least two different oligosaccharides is produced in and/or by a fungal, yeast, bacterial, insect, animal, plant or protozoan cell as described herein. The cell is chosen from the list comprising a bacterium, a yeast, a protozoan or a fungus, or, refers to a plant or animal cell. The latter bacterium preferably belongs to the phylum of the Proteobacteria or the phylum of the Firmicutes or the phylum of the Cyanobacteria or the phylum Deinococcus-Thermus. The latter bacterium belonging to the phylum Proteobacteria belongs preferably to the family Enterobacteriaceae, preferably to the species Escherichia coli. The latter bacterium preferably relates to any strain belonging to the species Escherichia coli such as but not limited to Escherichia coli B, Escherichia coli C, Escherichia coli W, Escherichia coli K12, Escherichia coli Nissle. More specifically, the latter term relates to cultivated Escherichia coli strains—designated as E. coli K12 strains—which are well-adapted to the laboratory environment, and, unlike wild type strains, have lost their ability to thrive in the intestine. Well-known examples of the E. coli K12 strains are K12 Wild type, W3110, MG1655, M182, MC1000, MC1060, MC1061, MC4100, JM101, NZN111 and AA200. Hence, this disclosure specifically relates to a mutated and/or transformed Escherichia coli cell or strain as indicated above wherein the E. coli strain is a K12 strain. More preferably, the Escherichia coli K12 strain is E. coli MG1655. The latter bacterium belonging to the phylum Firmicutes belongs preferably to the Bacilli, preferably Lactobacilliales, with members such as Lactobacillus lactis, Leuconostoc mesenteroides, or Bacillales with members such as from the genus Bacillus, such as Bacillus subtilis or, B. amyloliquefaciens. The latter bacterium belonging to the phylum Actinobacteria, preferably belonging to the family of the Corynebacteriaceae, with members Corynebacterium glutamicum or C. afermentans, or belonging to the family of the Streptomycetaceae with members Streptomyces griseus or S. fradiae. The latter yeast preferably belongs to the phylum of the Ascomycota or the phylum of the Basidiomycota or the phylum of the Deuteromycota or the phylum of the Zygomycetes. The latter yeast belongs preferably to the genus Saccharomyces (with members like e.g., Saccharomyces cerevisiae, S. bayanus, S. boulardii), Pichia (with members like e.g., Pichia pastoris, P. anomala, P. kluyveri), Komagataella, Hansenula, Kluyveromyces (with members like e.g., Kluyveromyces lactis, K marxianus, K thermotolerans), Debaromyces, Yarrowia (like e.g., Yarrowia lipolytica) or Starmerella (like e.g., Starmerella bombicola). The latter yeast is preferably selected from Pichia pastoris, Yarrowia hpolitica, Saccharomyces cerevisiae and Kluyveromyces lactis. The latter fungus belongs preferably to the genus Rhizopus, Dictyostelium, Penicillium, Mucor or Aspergillus. Plant cells include cells of flowering and non-flowering plants, as well as algal cells, for example, Chlamydomonas, Chlorella, etc. Preferably, the plant is a tobacco, alfalfa, rice, tomato, cotton, rapeseed, soy, maize or corn plant. The latter animal cell is preferably derived from non-human mammals (e.g., cattle, buffalo, pig, sheep, mouse, rat), birds (e.g., chicken, duck, ostrich, turkey, pheasant), fish (e.g., swordfish, salmon, tuna, sea bass, trout, catfish), invertebrates (e.g., lobster, crab, shrimp, clams, oyster, mussel, sea urchin), reptiles (e.g., snake, alligator, turtle), amphibians (e.g., frogs) or insects (e.g., fly, nematode) or is a genetically modified cell line derived from human cells excluding embryonic stem cells. Both human and non-human mammalian cells are preferably chosen from the list comprising an epithelial cell like e.g., a mammary epithelial cell, an embryonic kidney cell (e.g., HEK293 or HEK 293T cell), a fibroblast cell, a COS cell, a Chinese hamster ovary (CHO) cell, a murine myeloma cell like e.g., an N20, SP2/0 or YB2/0 cell, an NIH-3T3 cell, a non-mammary adult stem cell or derivatives thereof such as described in WO 2021067641. The latter insect cell is preferably derived from Spodoptera frupperda like e.g., Sf9 or Sf21 cells, Bombyx mori, Mamestra brassicae, Trichoplusia ni like e.g., BTI-TN-5B1-4 cells or Drosophila melanogaster like e.g., Drosophila S2 cells. The latter protozoan cell preferably is a Leishmania tarentolae cell.

In a preferred embodiment of the method of this disclosure, the cell is a viable Gram-negative bacterium that comprises a reduced or abolished synthesis of poly-N-acetyl-glucosamine (PNAG), Enterobacterial Common Antigen (ECA), cellulose, colanic acid, core oligosaccharides, Osmoregulated Periplasmic Glucans (OPG), Glucosylglycerol, glycan, and/or trehalose compared to a non-modified progenitor.

In a more preferred embodiment of the method, the reduced or abolished synthesis of poly-N-acetyl-glucosamine (PNAG), Enterobacterial Common Antigen (ECA), cellulose, colanic acid, core oligosaccharides, Osmoregulated Periplasmic Glucans (OPG), Glucosylglycerol, glycan, and/or trehalose is provided by a mutation in any one or more glycosyltransferases involved in the synthesis of any one of the poly-N-acetyl-glucosamine (PNAG), Enterobacterial Common Antigen (ECA), cellulose, colanic acid, core oligosaccharides, Osmoregulated Periplasmic Glucans (OPG), Glucosylglycerol, glycan, and/or trehalose, wherein the mutation provides for a deletion or lower expression of any one of the glycosyltransferases. The glycosyltransferases comprise glycosyltransferase genes encoding poly-N-acetyl-D-glucosamine synthase subunits, UDP-N-acetylglucosamine-undecaprenyl-phosphate N-acetylglucosaminephosphotransferase, Fuc4NAc (4-acetamido-4,6-dideoxy-D-galactose) transferase, UDP-N-acetyl-D-mannosaminuronic acid transferase, the glycosyltransferase genes encoding the cellulose synthase catalytic subunits, the cellulose biosynthesis protein, colanic acid biosynthesis glucuronosyltransferase, colanic acid biosynthesis galactosyltransferase, colanic acid biosynthesis fucosyltransferase, UDP-glucose:undecaprenyl-phosphate glucose-1-phosphate transferase, putative colanic biosynthesis glycosyl transferase, UDP-glucuronate:LPS(HepIII) glycosyltransferase, ADP-heptose-LPS heptosyltransferase 2, ADP-heptose:LPS heptosyltransferase 1, putative ADP-heptose:LPS heptosyltransferase 4, lipopolysaccharide core biosynthesis protein, UDP-glucose:(glucosyl)LPS α-1,2-glucosyltransferase, UDP-D-glucose:(glucosyl)LPS α-1,3-glucosyltransferase, UDP-D-galactose:(glucosyl)lipopolysaccharide-1,6-D-galactosyltransferase, lipopolysaccharide glucosyltransferase I, lipopolysaccharide core heptosyltransferase 3, β-1,6-galactofuranosyltransferase, undecaprenyl-phosphate 4-deoxy-4-formamido-L-arabinose transferase, lipid IVA 4-amino-4-deoxy-L-arabinosyltransferase, bactoprenol glucosyl transferase, putative family 2 glycosyltransferase, the osmoregulated periplasmic glucans (OPG) biosynthesis protein G, OPG biosynthesis protein H, glucosylglycerate phosphorylase, glycogen synthase, 1,4-α-glucan branching enzyme, 4-α-glucanotransferase and trehalose-6-phosphate synthase. In an exemplary embodiment, the cell is mutated in any one or more of the glycosyltransferases comprising pgaC, pgaD, rfe, rffT, rffM, bcsA, bcsB, bcsC, wcaA, wcaC, wcaE, wcaI, wcaJ, wcaL, waaH, waaF, waaC, waaU, waaZ, waaJ, waaO, waaB, waaS, waaG, waaQ, wbbI, arnC, arnT, yfdH, wbbK, opgG, opgH, ycjM, glgA, glgB, malQ, otsA and yaiP, wherein the mutation provides for a deletion or lower expression of any one of the glycosyltransferases.

In an alternative and/or additional preferred embodiment of the method, the reduced or abolished synthesis of poly-N-acetyl-glucosamine (PNAG) is provided by over-expression of a carbon storage regulator encoding gene, deletion of a Na+/H+ antiporter regulator encoding gene and/or deletion of the sensor histidine kinase encoding gene.

The microorganism or cell as used herein is capable to grow on a monosaccharide, disaccharide, oligosaccharide, polysaccharide, polyol, glycerol, a complex medium including molasses, corn steep liquor, peptone, tryptone, yeast extract or a mixture thereof like e.g., a mixed feedstock, preferably a mixed monosaccharide feedstock like e.g., hydrolyzed sucrose, as the main carbon source. With the term “complex medium” is meant a medium for which the exact constitution is not determined. With the term main is meant the most important carbon source for the bioproducts of interest, biomass formation, carbon dioxide and/or by-products formation (such as acids and/or alcohols, such as acetate, lactate, and/or ethanol), i.e., 20, 30, 40, 50, 60, 70, 75, 80, 85, 90, 95, 98, 99% of all the required carbon is derived from the above-indicated carbon source. In one embodiment of this disclosure, the carbon source is the sole carbon source for the organism, i.e., 100% of all the required carbon is derived from the above-indicated carbon source. Common main carbon sources comprise but are not limited to glucose, glycerol, fructose, maltose, lactose, arabinose, malto-oligosaccharides, maltotriose, sorbitol, xylose, rhamnose, sucrose, galactose, mannose, methanol, ethanol, trehalose, starch, cellulose, hemi-cellulose, molasses, corn-steep liquor, high-fructose syrup, acetate, citrate, lactate and pyruvate. With the term complex medium is meant a medium for which the exact constitution is not determined. Examples are molasses, corn steep liquor, peptone, tryptone or yeast extract.

In a further preferred embodiment, the microorganism or cell described herein is using a split metabolism having a production pathway and a biomass pathway as described in WO 2012/007481, which is herein incorporated by reference. The organism can, for example, be genetically modified to accumulate fructose-6-phosphate by altering the genes selected from the phosphoglucoisomerase gene, phosphofructokinase gene, fructose-6-phosphate aldolase gene, fructose isomerase gene, and/or fructose:PEP phosphotransferase gene.

According to this disclosure, the method as described herein preferably comprises a step of separating at least one of the oligosaccharides from the cultivation.

The terms “separating from the cultivation” means harvesting, collecting, or retrieving any of the oligosaccharides, preferably all of the oligosaccharides, from the cell and/or the medium of its growth.

Any one of the oligosaccharides can be separated in a conventional manner from the aqueous culture medium, in which the cell was grown. In case the oligosaccharide is still present in the cells producing the oligosaccharide mixture, conventional manners to free or to extract the oligosaccharide out of the cells can be used, such as cell destruction using high pH, heat shock, sonication, French press, homogenization, enzymatic hydrolysis, chemical hydrolysis, solvent hydrolysis, detergent, hydrolysis. The culture medium and/or cell extract together and separately can then be further used for separating the oligosaccharide. This preferably involves clarifying the oligosaccharide containing mixture to remove suspended particulates and contaminants, particularly cells, cell components, insoluble metabolites and debris produced by culturing the genetically modified cell. In this step, the oligosaccharide containing mixture can be clarified in a conventional manner. Preferably, the oligosaccharide containing mixture is clarified by centrifugation, flocculation, decantation and/or filtration. Another step of separating the oligosaccharide from the oligosaccharide containing mixture preferably involves removing substantially all the proteins, as well as peptides, amino acids, RNA and DNA and any endotoxins and glycolipids that could interfere with the subsequent separation step, from the oligosaccharide containing mixture, preferably after it has been clarified. In this step, proteins and related impurities can be removed from the oligosaccharide containing mixture in a conventional manner. Preferably, proteins, salts, by-products, color, endotoxins and other related impurities are removed from the oligosaccharide containing mixture by ultrafiltration, nanofiltration, two-phase partitioning, reverse osmosis, microfiltration, activated charcoal or carbon treatment, treatment with non-ionic surfactants, enzymatic digestion, tangential flow high-performance filtration, tangential flow ultrafiltration, electrophoresis (e.g., using slab-polyacrylamide or sodium dodecyl sulphate-polyacrylamide gel electrophoresis (PAGE)), affinity chromatography (using affinity ligands including e.g., DEAE-SEPHAROSE®, poly-L-lysine and polymyxin-B, endotoxin-selective adsorber matrices), ion exchange chromatography (such as but not limited to cation exchange, anion exchange, mixed bed ion exchange, inside-out ligand attachment), hydrophobic interaction chromatography and/or gel filtration (i.e., size exclusion chromatography), particularly by chromatography, more particularly by ion exchange chromatography or hydrophobic interaction chromatography or ligand exchange chromatography. With the exception of size exclusion chromatography, proteins and related impurities are retained by a chromatography medium or a selected membrane, the oligosaccharide remains in the oligosaccharide containing mixture.

In a further preferred embodiment, the methods as described herein also provide for a further purification of any one or more of the oligosaccharide(s) from the oligosaccharide mixture. A further purification of the oligosaccharide(s) may be accomplished, for example, by use of (activated) charcoal or carbon, nanofiltration, ultrafiltration or ion exchange to remove any remaining DNA, protein, LPS, endotoxins, or other impurity. Alcohols, such as ethanol, and aqueous alcohol mixtures can also be used. Another purification step is accomplished by crystallization, evaporation or precipitation of the product. Another purification step is to dry, e.g., spray dry, lyophilize, spray freeze dry, freeze spray dry, band dry, belt dry, vacuum band dry, vacuum belt dry, drum dry, roller dry, vacuum drum dry or vacuum roller dry the produced oligosaccharide(s).

In an exemplary embodiment, the separation and purification of at least one, preferably all, of the produced oligosaccharides is made in a process, comprising the following steps in any order:

• • a) contacting the cultivation or a clarified version thereof with a nanofiltration membrane with a molecular weight cut-off (MWCO) of 600-3500 Da ensuring the retention of produced oligosaccharide(s) and allowing at least a part of the proteins, salts, by-products, color and other related impurities to pass,
  • b) conducting a diafiltration process on the retentate from step a), using the membrane, with an aqueous solution of an inorganic electrolyte, followed by optional diafiltration with pure water to remove excess of the electrolyte,
  • c) and collecting the retentate enriched in the oligosaccharide(s) in the form of a salt from the cation of the electrolyte.

In an alternative exemplary embodiment, the separation and purification of at least one, preferably all, of the produced oligosaccharides is made in a process, comprising the following steps in any order: subjecting the cultivation or a clarified version thereof to two membrane filtration steps using different membranes, wherein—one membrane has a molecular weight cut-off of between about 300 Dalton to about 500 Dalton, and—the other membrane as a molecular weight cut-off of between about 600 Dalton to about 800 Dalton.

In an alternative exemplary embodiment, the separation and purification of at least one of the produced oligosaccharides is made in a process, comprising the following steps in any order comprising the step of treating the cultivation or a clarified version thereof with a strong cation exchange resin in H+-form and a weak anion exchange resin in free base form.

In an alternative exemplary embodiment, the separation and purification of at least one, preferably all, of the produced oligosaccharides is made in the following way. The cultivation comprising the produced oligosaccharide, biomass, medium components and contaminants, is applied to the following purification steps:

• • i) separation of biomass from the cultivation,
  • ii) cationic ion exchanger treatment for the removal of positively charged material,
  • iii) anionic ion exchanger treatment for the removal of negatively charged material,
  • iv) nanofiltration step and/or electrodialysis step,

wherein a purified solution comprising the produced oligosaccharide(s) at a purity of greater than or equal to 80 percent is provided. Optionally the purified solution is dried by any one or more drying steps chosen from the list comprising spray drying, lyophilization, spray freeze drying, freeze spray drying, band drying, belt drying, vacuum band drying, vacuum belt drying, drum drying, roller drying, vacuum drum drying and vacuum roller drying.

In an alternative exemplary embodiment, the separation and purification of at least one, preferably all, of the produced oligosaccharides is made in a process, comprising the following steps in any order: enzymatic treatment of the cultivation; removal of the biomass from the cultivation; ultrafiltration; nanofiltration; and a column chromatography step. Preferably, such column chromatography is a single column or a multiple column. Further preferably the column chromatography step is simulated moving bed chromatography. Such simulated moving bed chromatography preferably comprises i) at least 4 columns, wherein at least one column comprises a weak or strong cation exchange resin; and/or ii) four zones I, II, III and IV with different flow rates; and/or iii) an eluent comprising water; and/or iv) an operating temperature of 15 degrees to 60 degrees centigrade.

In a specific embodiment, this disclosure provides the produced oligosaccharide or oligosaccharide mixture that is dried to powder by any one or more drying steps chosen from the list comprising spray drying, lyophilization, spray freeze drying, freeze spray drying, band drying, belt drying, vacuum band drying, vacuum belt drying, drum drying, roller drying, vacuum drum drying and vacuum roller drying, wherein the dried powder contains <15 percent-wt. of water, preferably <10 percent-wt. of water, more preferably <7 percent-wt. of water, most preferably <5 percent-wt. of water.

In a second aspect, this disclosure provides for the use of a method as described herein for the production of a mixture comprising at least two different oligosaccharides.

For identification of the oligosaccharides in the mixture comprising at least two different oligosaccharides produced in the cell as described herein, the monomeric building blocks (e.g., the monosaccharide or glycan unit composition), the anomeric configuration of side chains, the presence and location of substituent groups, degree of polymerization/molecular weight and the linkage pattern can be identified by standard methods known in the art, such as, e.g., methylation analysis, reductive cleavage, hydrolysis, GC-MS (gas chromatography-mass spectrometry), MALDI-MS (Matrix-assisted laser desorption/ionization-mass spectrometry), ESI-MS (Electrospray ionization-mass spectrometry), HPLC (High-Performance Liquid chromatography with ultraviolet or refractive index detection), HPAEC-PAD (High-Performance Anion-Exchange chromatography with Pulsed Amperometric Detection), CE (capillary electrophoresis), IR (infrared)/Raman spectroscopy, and NMR (Nuclear magnetic resonance) spectroscopy techniques. The crystal structure can be solved using, e.g., solid-state NMR, FT-IR (Fourier transform infrared spectroscopy), and WAXS (wide-angle X-ray scattering). The degree of polymerization (DP), the DP distribution, and polydispersity can be determined by, e.g., viscosimetry and SEC (SEC-HPLC, high performance size-exclusion chromatography). To identify the monomeric components of the saccharide methods such as, e.g., acid-catalyzed hydrolysis, HPLC (high performance liquid chromatography) or GLC (gas-liquid chromatography) (after conversion to alditol acetates) may be used. To determine the glycosidic linkages, the saccharide is methylated with methyl iodide and strong base in DMSO, hydrolysis is performed, a reduction to partially methylated alditols is achieved, an acetylation to methylated alditol acetates is performed, and the analysis is carried out by GLC/MS (gas-liquid chromatography coupled with mass spectrometry). To determine the oligosaccharide sequence, a partial depolymerization is carried out using an acid or enzymes to determine the structures. To identify the anomeric configuration, the oligosaccharide is subjected to enzymatic analysis, e.g., it is contacted with an enzyme that is specific for a particular type of linkage, e.g., beta-galactosidase, or alpha-glucosidase, etc., and NMR may be used to analyze the products.

Products Comprising the Oligosaccharide Mixture

In some embodiments, an oligosaccharide mixture produced as described herein is incorporated into a food (e.g., human food or feed), dietary supplement, pharmaceutical ingredient, cosmetic ingredient or medicine. In some embodiments, the oligosaccharide mixture is mixed with one or more ingredients suitable for food, feed, dietary supplement, pharmaceutical ingredient, cosmetic ingredient or medicine.

In some embodiments, the dietary supplement comprises at least one prebiotic ingredient and/or at least one probiotic ingredient.

A “prebiotic” is a substance that promotes growth of microorganisms beneficial to the host, particularly microorganisms in the gastrointestinal tract. In some embodiments, a dietary supplement provides multiple prebiotics, including the oligosaccharide mixture produced and/or purified by a process disclosed in this specification, to promote growth of one or more beneficial microorganisms. Examples of prebiotic ingredients for dietary supplements include other prebiotic molecules (such as HMOs) and plant polysaccharides (such as inulin, pectin, b-glucan and xylooligosaccharide). A “probiotic” product typically contains live microorganisms that replace or add to gastrointestinal microflora, to the benefit of the recipient. Examples of such microorganisms include Lactobacillus species (for example, L. acidophilus and L. bulgaricus), Bifidobacterium species (for example, B. animalis, B. longum and B. infantis (e.g., Bi-26)), and Saccharomyces boulardii. In some embodiments, an oligosaccharide mixture produced and/or purified by a process of this specification is orally administered in combination with such microorganism.

Examples of further ingredients for dietary supplements include disaccharides (such as lactose), monosaccharides (such as glucose and galactose), thickeners (such as gum arabic), acidity regulators (such as trisodium citrate), water, skimmed milk, and flavorings.

In some embodiments, the oligosaccharide mixture is incorporated into a human baby food (e.g., infant formula). Infant formula is generally a manufactured food for feeding to infants as a complete or partial substitute for human breast milk. In some embodiments, infant formula is sold as a powder and prepared for bottle- or cup-feeding to an infant by mixing with water. The composition of infant formula is typically designed to be roughly mimic human breast milk. In some embodiments, an oligosaccharide mixture produced and/or purified by a process in this specification is included in infant formula to provide nutritional benefits similar to those provided by the oligosaccharides in human breast milk. In some embodiments, the oligosaccharide mixture is mixed with one or more ingredients of the infant formula. Examples of infant formula ingredients include non-fat milk, carbohydrate sources (e.g., lactose), protein sources (e.g., whey protein concentrate and casein), fat sources (e.g., vegetable oils—such as palm, high oleic safflower oil, rapeseed, coconut and/or sunflower oil; and fish oils), vitamins (such as vitamins A, B6, B12, C and D), minerals (such as potassium citrate, calcium citrate, magnesium chloride, sodium chloride, sodium citrate and calcium phosphate) and possibly human milk oligosaccharides (HMOs). Such HMOs may include, for example, DiFL, lacto-N-triose II, LNT, LNnT, lacto-N-fucopentaose I, lacto-N-neofucopentaose, lacto-N-fucopentaose II, lacto-N-fucopentaose III, lacto-N-fucopentaose V, lacto-N-neofucopentaose V, lacto-N-difucohexaose I, lacto-N-difucohexaose II, 6′-galactosyllactose, 3′-galactosyllactose, lacto-N-hexaose and lacto-N-neohexaose.

In some embodiments, the one or more infant formula ingredients comprise non-fat milk, a carbohydrate source, a protein source, a fat source, and/or a vitamin and mineral.

In some embodiments, the one or more infant formula ingredients comprise lactose, whey protein concentrate and/or high oleic safflower oil.

In some embodiments, the oligosaccharide mixture's concentration in the infant formula is approximately the same concentration as the oligosaccharide's concentration generally present in human breast milk. In some embodiments, the concentration of each of the single oligosaccharides in the mixture of oligosaccharides in the infant formula is approximately the same concentration as the concentration of that oligosaccharide generally present in human breast milk.

In some embodiments, the oligosaccharide mixture is incorporated into a feed preparation, wherein the feed is chosen from the list comprising pet food, animal milk replacer, veterinary product, post weaning feed, or creep feed.

Each embodiment disclosed in the context of one aspect of this disclosure, is also disclosed in the context of all other aspects of this disclosure, unless explicitly stated otherwise.

Unless defined otherwise, all technical and scientific terms used herein generally have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein and the laboratory procedures in cell culture, molecular genetics, organic chemistry and nucleic acid chemistry and hybridization described above and below are those well-known and commonly employed in the art. Standard techniques are used for nucleic acid and peptide synthesis. Generally, purification steps are performed according to the manufacturer's specifications.

Further advantages follow from the specific embodiments, the examples and the attached drawings. It goes without saying that the abovementioned features and the features that are still to be explained below can be used not only in the respectively specified combinations, but also in other combinations or on their own, without departing from the scope of this disclosure.

This disclosure relates to following specific embodiments:

• • 1. A method to produce a mixture of at least two different oligosaccharides by a cell, the method comprising the steps of:
    • i. providing a cell expressing one glycosyltransferase and capable to synthesize one nucleotide-sugar, wherein the nucleotide-sugar is donor for the glycosyltransferase, and
    • ii. cultivating the cell under conditions permissive to express the glycosyltransferase and to synthesize the nucleotide-sugar, and
    • iii. addition of at least two acceptors to the cultivation enabling the cell to produce at least two oligosaccharides, preferably any one of the acceptors is a di- or oligosaccharide,
    • iv. preferably, separating at least one of the oligosaccharides from the cultivation, more preferably separating all of the oligosaccharides from the cultivation.
  • 2. Method according to embodiment 1, wherein the cell is a metabolically engineered cell modified with at least one gene expression module, characterized in that the expression from any one of the at least one expression modules is either constitutive or is created by a natural inducer.
  • 3. Method according to any one of embodiment 1 or 2, wherein the cell produces a mixture of three or more different oligosaccharides.
  • 4. Method according to any one of embodiment 1 to 3, wherein the cell produces a mixture of different oligosaccharides with at least two oligosaccharides differing in degree of polymerization.
  • 5. Method according to any one of embodiment 1 to 4, wherein the glycosyltransferase is chosen from the list comprising fucosyltransferases, sialyltransferases, galactosyltransferases, glucosyltransferases, mannosyltransferases, N-acetylglucosaminyltransferases, N-acetylgalactosaminyltransferases, N-acetylmannosaminyltransferases, xylosyltransferases, glucuronyltransferases, galacturonyltransferases, glucosaminyltransferases, N-glycolylneuraminyltransferases, rhamnosyltransferases.
  • 6. Method according to any one of embodiment 1 to 5 wherein the cell is modified in the expression or activity of the glycosyltransferase.
  • 7. Method according to any one of embodiment 1 to 6 wherein the glycosyltransferase is a fucosyltransferase and the donor nucleotide-sugar is GDP-Fucose (GDP-Fuc).
  • 8. Method according to any one of embodiment 1 to 7 wherein glycosyltransferase is a sialyltransferase and the donor nucleotide-sugar is CMP-N-acetylneuraminic acid (CMP-Neu5Ac).
  • 9. Method according to any one of embodiment 1 to 8 wherein the glycosyltransferase is an N-acetylglucosaminyltransferase and the donor nucleotide-sugar is UDP-N-acetylglucosamine (UDP-GlcNAc).
  • 10. Method according to any one of embodiment 1 to 9 wherein the glycosyltransferase is a galactosyltransferase and the donor nucleotide-sugar is UDP-galactose (UDP-Gal).
  • 11. Method according to any one of embodiment 1 to 10, wherein the nucleotide-sugar is chosen from the list comprising GDP-Fuc, CMP-Neu5Ac, UDP-GlcNAc, UDP-Gal, UDP-N-acetylgalactosamine (UDP-GalNAc), UDP-N-acetylmannosamine (UDP-ManNAc), GDP-mannose (GDP-Man), UDP-glucose (UDP-Glc), CMP-N-glycolylneuraminic acid (CMP-Neu5Gc), UDP-glucuronate, UDP-galacturonate, GDP-rhamnose, UDP-xylose.
  • 12. Method according to any one of embodiments 1 to 11, wherein any one of the acceptors has a degree of polymerization of 3 or more, preferably wherein all of the acceptors have a degree of polymerization of 3 or more.
  • 13. Method according to any one of embodiment 1 to 12, wherein all the acceptors have a different degree of polymerization.
  • 14. Method according to any one of embodiment 1 to 13, wherein the cultivation is supplemented with at least 3 acceptors for the production of the oligosaccharide mixture.
  • 15. Method according to any one of embodiment 1 to 14, wherein the oligosaccharide mixture comprises at least one oligosaccharide that is fucosylated, sialylated, galactosylated, glucosylated, xylosylated, mannosylated, contains an N-acetylglucosamine, contains an N-acetylneuraminate, contains an N-glycolylneuraminate, contains an N-acetylgalactosamine, contains a rhamnose, contains a glucuronate, contains a galacturonate, and/or contains an N-acetylmannosamine.
  • 16. Method according to any one of embodiment 1 to 15, wherein the oligosaccharide mixture comprises at least one fucosylated oligosaccharide.
  • 17. Method according to any one of embodiment 1 to 16, wherein the oligosaccharide mixture comprises at least one sialylated oligosaccharide.
  • 18. Method according to any one of embodiment 1 to 17, wherein the oligosaccharide mixture comprises at least one oligosaccharide that comprises an N-acetylglucosamine monosaccharide unit.
  • 19. Method according to any one of embodiment 1 to 18, wherein the oligosaccharide mixture comprises at least one galactosylated oligosaccharide.
  • 20. Method according to any one of embodiment 1 to 16, wherein all the oligosaccharides in the mixture are fucosylated oligosaccharides.
  • 21. Method according to embodiment 1 to 16 and 20, wherein the cell produces three fucosylated oligosaccharides.
  • 22. Method according to any one of embodiment 1 to 21, wherein the acceptors are produced by methods comprising extraction from natural sources, biotechnological processes, physical processes, chemical processes, and combinations thereof.
  • 23. Method according to any one of embodiment 1 to 22, wherein any one of the acceptors is completely converted into any one of the oligosaccharides.
  • 24. Method according to any one of embodiment 1 to 23, wherein the cell is further metabolically engineered for:
    • i) modified expression of an endogenous membrane protein, and/or
    • ii) modified activity of an endogenous membrane protein, and/or
    • iii) expression of a homologous membrane protein, and/or
    • iv) expression of a heterologous membrane protein,
    • wherein the membrane protein is involved in the secretion of any one of the oligosaccharides from the cell, preferably wherein the membrane protein is involved in the secretion of all of the oligosaccharides from the cell.
  • 25. Method according to any one of embodiment 1 to 24, wherein the cell is further metabolically engineered for:
    • i) modified expression of an endogenous membrane protein, and/or
    • ii) modified activity of an endogenous membrane protein, and/or
    • iii) expression of a homologous membrane protein, and/or
    • iv) expression of a heterologous membrane protein,
    • wherein the membrane protein is involved in the uptake of a precursor for the synthesis of any one of the oligosaccharides of the mixture, preferably wherein the membrane protein is involved in the uptake of all of the required precursors, more preferably wherein the membrane protein is involved in the uptake of all of the acceptors.
  • 26. Method according to any one of embodiment 1 to 25, wherein any one of the oligosaccharides is a mammalian milk oligosaccharide, preferably wherein all the oligosaccharides are mammalian milk oligosaccharides.
  • 27. Method according to any one of embodiment 1 to 25, wherein any one of the oligosaccharide is an antigen of the human ABO blood group system, preferably wherein all the oligosaccharides are antigens of the human ABO blood group system.
  • 28. Method according to any one of embodiment 1 to 27, wherein the cell is selected from the group comprising microorganism, plant, or animal cells, preferably the microorganism is a bacterium, fungus or a yeast, preferably the plant is a rice, cotton, rapeseed, soy, maize or corn plant, preferably the animal is an insect, fish, bird or non-human mammal, preferably the animal cell is a mammalian cell line.
  • 29. Method according to any one of embodiment 1 to 28, wherein the cell is a cell of a bacterium, preferably of an Escherichia coli strain, more preferably of an Escherichia coli strain that is a K-12 strain, even more preferably the Escherichia coli K-12 strain is E. coli MG1655.
  • 30. Method according to any one of embodiment 1 to 28, wherein the cell is a yeast cell.
  • 31. The method according to any one of embodiment 1 to 30, wherein the separation comprises at least one of the following steps: clarification, ultrafiltration, nanofiltration, reverse osmosis, microfiltration, activated charcoal or carbon treatment, tangential flow high-performance filtration, tangential flow ultrafiltration, affinity chromatography, ion exchange chromatography, hydrophobic interaction chromatography and/or gel filtration, ligand exchange chromatography.
  • 32. The method according to any one of embodiment 1 to 31 further comprising purification of any one of the oligosaccharides from the cell.
  • 33. The method according to any one of embodiment 1 to 32, wherein the purification comprises at least one of the following steps: use of activated charcoal or carbon, use of charcoal, nanofiltration, ultrafiltration or ion exchange, use of alcohols, use of aqueous alcohol mixtures, crystallization, evaporation, precipitation, drying, spray drying or lyophilization.
  • 34. Use of a method according to any one of embodiments 1 to 33 for the production of a mixture of at least two different oligosaccharides.

Moreover, this disclosure relates to the following preferred specific embodiments:

• • 1. A method to produce a mixture of at least two different oligosaccharides by a cell, preferably a single cell, the method comprising the steps of:
    • i. providing a cell, preferably a single cell, that is capable to express a glycosyltransferase and is capable to synthesize a nucleotide-sugar, wherein the nucleotide-sugar is donor for the glycosyltransferase, and
    • ii. cultivating the cell under conditions permissive to express the glycosyltransferase and to synthesize the nucleotide-sugar, and
    • iii. addition of at least two acceptors to the cultivation enabling the cell to produce at least two oligosaccharides, preferably any one of the acceptors is a di- or oligosaccharide,
    • iv. preferably, separating at least one of the oligosaccharides from the cultivation, more preferably separating all of the oligosaccharides from the cultivation.
  • 2. Method according to preferred embodiment 1, wherein any one of the acceptors is a disaccharide or a mammalian milk oligosaccharide (MMO), preferably any one of the acceptors is a mammalian milk oligosaccharide.
  • 3. Method according to any one of preferred embodiment 1 or 2, wherein the cell is a cell metabolically engineered for the production of the mixture and/or is modified with at least one gene expression module, characterized in that the expression from any one of the at least one expression modules is either constitutive or is created by a natural inducer.
  • 4. Method according to any one of preferred embodiment 1 to 3, wherein the cell comprises multiple copies of the same coding DNA sequence encoding for one protein.
  • 5. Method according to any one of preferred embodiment 1 to 4, wherein the cell produces a mixture of three or more different oligosaccharides.
  • 6. Method according to any one of preferred embodiment 1 to 5, wherein the cell produces a mixture of different oligosaccharides with at least two oligosaccharides differing in degree of polymerization.
  • 7. Method according to any one of preferred embodiment 1 to 6, wherein the glycosyltransferase is chosen from the list comprising fucosyltransferases, sialyltransferases, galactosyltransferases, glucosyltransferases, mannosyltransferases, N-acetylglucosaminyltransferases, N-acetylgalactosaminyltransferases, N-acetylmannosaminyltransferases, xylosyltransferases, glucuronyltransferases, galacturonyltransferases, glucosaminyltransferases, N-glycolylneuraminyltransferases, rhamnosyltransferases, N-acetylrhamnosyltransferases, UDP-4-amino-4,6-dideoxy-N-acetyl-beta-L-altrosamine transaminases, UDP-N-acetylglucosamine enolpyruvyl transferases and fucosaminyltransferases,
    • preferably, the fucosyltransferase is chosen from the list comprising alpha-1,2-fucosyltransferase, alpha-1,3-fucosyltransferase, alpha-1,4-fucosyltransferase and alpha-1,6-fucosyltransferase,
    • preferably, the sialyltransferase is chosen from the list comprising alpha-2,3-sialyltransferase, alpha-2,6-sialyltransferase and alpha-2,8-sialyltransferase,
    • preferably, the galactosyltransferase is chosen from the list comprising beta-1,3-galactosyltransferase, N-acetylglucosamine beta-1,3-galactosyltransferase, beta-1,4-galactosyltransferase, N-acetylglucosamine beta-1,4-galactosyltransferase, alpha-1,3-galactosyltransferase and alpha-1,4-galactosyltransferase,
    • preferably, the glucosyltransferase is chosen from the list comprising alpha-glucosyltransferase, beta-1,2-glucosyltransferase, beta-1,3-glucosyltransferase and beta-1,4-glucosyltransferase,
    • preferably, the mannosyltransferase is chosen from the list comprising alpha-1,2-mannosyltransferase, alpha-1,3-mannosyltransferase and alpha-1,6-mannosyltransferase,
    • preferably, the N-acetylglucosaminyltransferase is chosen from the list comprising galactoside beta-1,3-N-acetylglucosaminyltransferase and beta-1,6-N-acetylglucosaminyltransferase,
    • preferably, the N-acetylgalactosaminyltransferase is an alpha-1,3-N-acetylgalactosaminyltransferase.
  • 8. Method according to any one of preferred embodiment 1 to 7, wherein the cell is modified in the expression or activity of the glycosyltransferase.
  • 9. Method according to any one of preferred embodiment 1 to 8, wherein the glycosyltransferase is a fucosyltransferase and the donor nucleotide-sugar is GDP-Fucose (GDP-Fuc).
  • 10. Method according to any one of preferred embodiment 1 to 9, wherein glycosyltransferase is a sialyltransferase and the donor nucleotide-sugar is CMP-N-acetylneuraminic acid (CMP-Neu5Ac).
  • 11. Method according to any one of preferred embodiment 1 to 10, wherein the glycosyltransferase is an N-acetylglucosaminyltransferase and the donor nucleotide-sugar is UDP-N-acetylglucosamine (UDP-GlcNAc).
  • 12. Method according to any one of preferred embodiment 1 to 11, wherein the glycosyltransferase is a galactosyltransferase and the donor nucleotide-sugar is UDP-galactose (UDP-Gal).
  • 13. Method according to any one of preferred embodiment 1 to 12, wherein the glycosyltransferase is an N-acetylgalactosaminyltransferase and the donor nucleotide-sugar is UDP-N-acetylgalactosamine (UDP-GalNAc).
  • 14. Method according to any one of preferred embodiment 1 to 13, wherein the glycosyltransferase is an N-acetylmannosaminyltransferase and the donor nucleotide-sugar is UDP-N-acetylmannosamine (UDP-ManNAc).
  • 15. Method according to any one of preferred embodiment 1 to 14, wherein the nucleotide-sugar is chosen from the list comprising GDP-Fuc, CMP-Neu5Ac, UDP-GlcNAc, UDP-Gal, UDP-N-acetylgalactosamine (UDP-GalNAc), UDP-N-acetylmannosamine (UDP-ManNAc), GDP-mannose (GDP-Man), UDP-glucose (UDP-Glc), UDP-2-acetamido-2,6-dideoxy-L-arabino-4-hexulose, UDP-2-acetamido-2,6-dideoxy-L-lyxo-4-hexulose, UDP-N-acetyl-L-rhamnosamine (UDP-L-RhaNAc or UDP-2-acetamido-2,6-dideoxy-L-mannose), dTDP-N-acetylfucosamine, UDP-N-acetylfucosamine (UDP-L-FucNAc or UDP-2-acetamido-2,6-dideoxy-L-galactose), UDP-N-acetyl-L-pneumosamine (UDP-L-PneNAC or UDP-2-acetamido-2,6-dideoxy-L-talose), UDP-N-acetylmuramic acid, UDP-N-acetyl-L-quinovosamine (UDP-L-QuiNAc or UDP-2-acetamido-2,6-dideoxy-L-glucose), GDP-L-quinovose, CMP-N-glycolylneuraminic acid (CMP-Neu5Gc), CMP-Neu4Ac, CMP-Neu5Ac9N₃, CMP-Neu4,5Ac₂, CMP-Neu5,7Ac₂, CMP-Neu5,9Ac₂, CMP-Neu5,7(8,9)Ac₂, UDP-glucuronate, UDP-galacturonate, GDP-rhamnose, UDP-xylose.
  • 16. Method according to any one of preferred embodiments 1 to 15, wherein any one of the acceptors has a degree of polymerization of 3 or more, preferably wherein all of the acceptors have a degree of polymerization of 3 or more.
  • 17. Method according to any one of preferred embodiment 1 to 16, wherein all the acceptors have a different degree of polymerization.
  • 18. Method according to any one of preferred embodiment 1 to 17, wherein the cultivation is supplemented with at least 3 acceptors for the production of the oligosaccharide mixture, preferably with at least 4 acceptors, more preferably with at least 5 acceptors.
  • 19. Method according to any one of preferred embodiment 1 to 18, wherein the oligosaccharide mixture comprises at least one oligosaccharide that is fucosylated, sialylated, galactosylated, glucosylated, xylosylated, mannosylated, contains an N-acetylglucosamine, contains an N-acetylneuraminate, contains an N-glycolylneuraminate, contains an N-acetylgalactosamine, contains a rhamnose, contains a glucuronate, contains a galacturonate, and/or contains an N-acetylmannosamine.
  • 20. Method according to any one of preferred embodiment 1 to 19, wherein the oligosaccharide mixture comprises charged and/or neutral oligosaccharides, preferably wherein at least one of the charged oligosaccharides is a sialylated oligosaccharide.
  • 21. Method according to any one of preferred embodiment 1 to 19, wherein the oligosaccharide mixture comprises fucosylated and/or non-fucosylated neutral oligosaccharides.
  • 22. Method according to any one of preferred embodiment 1 to 21, wherein the oligosaccharide mixture comprises at least one fucosylated oligosaccharide.
  • 23. Method according to any one of preferred embodiment 1 to 20, wherein the oligosaccharide mixture comprises at least one sialylated oligosaccharide.
  • 24. Method according to any one of preferred embodiment 1 to 23, wherein the oligosaccharide mixture comprises at least one oligosaccharide that comprises an N-acetylglucosamine monosaccharide unit.
  • 25. Method according to any one of preferred embodiment 1 to 24, wherein the oligosaccharide mixture comprises at least one galactosylated oligosaccharide.
  • 26. Method according to preferred embodiment 21, wherein all the oligosaccharides in the mixture are fucosylated oligosaccharides.
  • 27. Method according to preferred embodiment 1 to 26, wherein the cell produces three fucosylated oligosaccharides.
  • 28. Method according to any one of preferred embodiment 1 to 27, wherein the acceptors are produced by methods comprising extraction from natural sources, biotechnological processes, physical processes, chemical processes, and combinations thereof.
  • 29. Method according to any one of preferred embodiment 1 to 28, wherein any one of the acceptors is completely converted into any one of the oligosaccharides.
  • 30. Method according to any one of preferred embodiment 1 to 29, wherein the cell produces the mixture of at least two oligosaccharides intracellularly and wherein a fraction or substantially all of the produced oligosaccharides remains intracellularly and/or is excreted outside the cell via passive or active transport.
  • 31. Method according to any one of preferred embodiment 1 to 30, wherein the cell is further metabolically engineered for:
    • i) modified expression of an endogenous membrane protein, and/or
    • ii) modified activity of an endogenous membrane protein, and/or
    • iii) expression of a homologous membrane protein, and/or
    • iv) expression of a heterologous membrane protein,
    • wherein the membrane protein is involved in the secretion of any one of the oligosaccharides from the cell, preferably wherein the membrane protein is involved in the secretion of all of the oligosaccharides from the cell.
  • 32. Method according to any one of preferred embodiment 1 to 31, wherein the cell is further metabolically engineered for:
    • i) modified expression of an endogenous membrane protein, and/or
    • ii) modified activity of an endogenous membrane protein, and/or
    • iii) expression of a homologous membrane protein, and/or
    • iv) expression of a heterologous membrane protein,
    • wherein the membrane protein is involved in the uptake of a precursor for the synthesis of any one of the oligosaccharides of the mixture, preferably wherein the membrane protein is involved in the uptake of all of the required precursors, more preferably wherein the membrane protein is involved in the uptake of all of the acceptors.
  • 33. Method according to any one of preferred embodiment 31 or 32, wherein the membrane protein is chosen from the list comprising porters, P-P-bond-hydrolysis-driven transporters, β-barrel porins, auxiliary transport proteins, putative transport proteins and phosphotransfer-driven group translocators,
    • preferably, the porters comprise MFS transporters, sugar efflux transporters and siderophore exporters,
    • preferably, the P-P-bond-hydrolysis-driven transporters comprise ABC transporters and siderophore exporters.
  • 34. Method according to any one of preferred embodiment 31 to 33, wherein the membrane protein provides improved production and/or enabled and/or enhanced efflux of the mixture of at least two oligosaccharides.
  • 35. Method according to any one of preferred embodiment 1 to 34, wherein the cell resists the phenomenon of lactose killing when grown in an environment in which lactose is combined with one or more other carbon source(s).
  • 36. Method according to any one of preferred embodiment 1 to 35, wherein the cell comprises a modification for reduced production of acetate compared to a non-modified progenitor.
  • 37. Method according to preferred embodiment 36, wherein the cell comprises a lower or reduced expression and/or abolished, impaired, reduced or delayed activity of any one or more of the proteins comprising beta-galactosidase, galactoside 0-acetyltransferase, N-acetylglucosamine-6-phosphate deacetylase, glucosamine-6-phosphate deaminase, N-acetylglucosamine repressor, ribonucleotide monophosphatase, EIICBA-Nag, UDP-glucose:undecaprenyl-phosphate glucose-1-phosphate transferase, L-fuculokinase, L-fucose isomerase, N-acetylneuraminate lyase, N-acetylmannosamine kinase, N-acetylmannosamine-6-phosphate 2-epimerase, EIIAB-Man, EIIC-Man, EIID-Man, ushA, galactose-1-phosphate uridylyltransferase, glucose-1-phosphate adenylyltransferase, glucose-1-phosphatase, ATP-dependent 6-phosphofructokinase isozyme 1, ATP-dependent 6-phosphofructokinase isozyme 2, glucose-6-phosphate isomerase, aerobic respiration control protein, transcriptional repressor IclR, lon protease, glucose-specific translocating phosphotransferase enzyme IIBC component ptsG, glucose-specific translocating phosphotransferase (PTS) enzyme IIBC component malX, enzyme IIA^Glc, beta-glucoside specific PTS enzyme II, fructose-specific PTS multiphosphoryl transfer protein FruA and FruB, ethanol dehydrogenase aldehyde dehydrogenase, pyruvate-formate lyase, acetate kinase, phosphoacyltransferase, phosphate acetyltransferase, pyruvate decarboxylase compared to a non-modified progenitor.
  • 38. Method according to any one of preferred embodiment 1 to 37, wherein the cell is capable to produce phosphoenolpyruvate (PEP).
  • 39. Method according to any one of preferred embodiment 1 to 38, wherein the cell is modified for enhanced production and/or supply of phosphoenolpyruvate (PEP) compared to a non-modified progenitor.
  • 40. Method according to any one of preferred embodiment 1 to 39, wherein any one of the oligosaccharides is a mammalian milk oligosaccharide, preferably wherein all the oligosaccharides are mammalian milk oligosaccharides.
  • 41. Method according to any one of preferred embodiment 1 to 40, wherein any one of the oligosaccharide is an antigen of the human ABO blood group system, preferably wherein all the oligosaccharides are antigens of the human ABO blood group system.
  • 42. Method according to any one of preferred embodiment 1 to 41, wherein the cell is a bacterium, fungus, yeast, a plant cell, an animal cell, or a protozoan cell,
    • preferably the bacterium is an Escherichia coli strain, more preferably an Escherichia coli strain that is a K-12 strain, even more preferably the Escherichia coli K-12 strain is E. coli MG1655,
    • preferably the fungus belongs to a genus chosen from the group comprising Rhizopus, Dictyostelium, Penicillium, Mucor or Aspergillus,
    • preferably the yeast belongs to a genus chosen from the group comprising Saccharomyces, Zygosaccharomyces, Pichia, Komagataella, Hansenula, Yarrowia, Starmerella, Kluyveromyces or Debaromyces,
    • preferably the plant cell is an algal cell or is derived from tobacco, alfalfa, rice, tomato, cotton, rapeseed, soy, maize, or corn plant,
    • preferably the animal cell is derived from non-human mammals, birds, fish, invertebrates, reptiles, amphibians or insects or is a genetically modified cell line derived from human cells excluding embryonic stem cells, more preferably the human and non-human mammalian cell is an epithelial cell, an embryonic kidney cell, a fibroblast cell, a COS cell, a Chinese hamster ovary (CHO) cell, a murine myeloma cell, an NIH-3T3 cell, a non-mammary adult stem cell or derivatives thereof, more preferably the insect cell is derived from Spodoptera frugiperda, Bombyx mori, Mamestra brassicae, Trichoplusia ni or Drosophila melanogaster,
    • preferably the protozoan cell is a Leishmania tarentolae cell.
  • 43. Method according to preferred embodiment 42, wherein the cell is a viable Gram-negative bacterium that comprises a reduced or abolished synthesis of poly-N-acetyl-glucosamine (PNAG), Enterobacterial Common Antigen (ECA), cellulose, colanic acid, core oligosaccharides, Osmoregulated Periplasmic Glucans (OPG), Glucosylglycerol, glycan, and/or trehalose compared to a non-modified progenitor.
  • 44. The method according to any one of preferred embodiment 1 to 43, wherein the separation comprises at least one of the following steps: clarification, ultrafiltration, nanofiltration, two-phase partitioning, reverse osmosis, microfiltration, activated charcoal or carbon treatment, treatment with non-ionic surfactants, enzymatic digestion, tangential flow high-performance filtration, tangential flow ultrafiltration, affinity chromatography, ion exchange chromatography, hydrophobic interaction chromatography and/or gel filtration, ligand exchange chromatography.
  • 45. The method according to any one of preferred embodiment 1 to 44 further comprising purification of any one of the oligosaccharides from the cell.
  • 46. The method according to preferred embodiment 45, wherein the purification comprises at least one of the following steps: use of activated charcoal or carbon, use of charcoal, nanofiltration, ultrafiltration, electrophoresis, enzymatic treatment or ion exchange, use of alcohols, use of aqueous alcohol mixtures, crystallization, evaporation, precipitation, drying, spray drying, lyophilization, spray freeze drying, freeze spray drying, band drying, belt drying, vacuum band drying, vacuum belt drying, drum drying, roller drying, vacuum drum drying or vacuum roller drying.
  • 47. Use of a method according to any one of preferred embodiments 1 to 46 for the production of a mixture of at least two different oligosaccharides.

This disclosure will be described in more detail in the examples. The following examples will serve as further illustration and clarification of this disclosure and are not intended to be limiting.

EXAMPLES

Example 1. Materials and Methods Escherichia coli

Media

The Luria Broth (LB) medium comprised 1% tryptone peptone (Difco, Erembodegem, Belgium), 0.5% yeast extract (Difco) and 0.5% sodium chloride (VWR. Leuven, Belgium). The minimal medium used in the cultivation experiments in 96-well plates or in shake flasks contained 2.00 g/L NH₄Cl, 5.00 g/L (NH₄)₂SO₄, 2.993 g/L KH₂PO₄, 7.315 g/L K2HPO₄, 8.372 g/L MOPS, 0.5 g/L NaCl, 0.5 g/L MgSO₄·7H₂O, 30 g/L sucrose or 30 g/L glycerol, 1 ml/L vitamin solution, 100 μl/L molybdate solution, and 1 mL/L selenium solution. As specified in the respective examples, 20 g/L lactose, 20 g/L 2′FL, 20 g/L 3-FL, 20 g/L 3′SL, 20 g/L 6′SL, 20 g/L LacNAc and/or 20 g/L LNB were additionally added to the medium as acceptor(s). The minimal medium was set to a pH of 7 with 1M KOH. Vitamin solution comprised 3.6 g/L FeCl₂·4H₂O, 5 g/L CaCl₂·2H₂O, 1.3 g/L MnCl₂·2H₂O, 0.38 g/L CuCl₂·2H₂O, 0.5 g/L CoCl₂·6H₂O, 0.94 g/L ZnCl₂, 0.0311 g/L H₃BO₄, 0.4 g/L Na₂EDTA·2H₂O and 1.01 g/L thiamine·HCl. The molybdate solution contained 0.967 g/L NaMoO4·2H₂O. The selenium solution contained 42 g/L SeO₂.

The minimal medium for fermentations contained 6.75 g/L NH₄Cl, 1.25 g/L (NH₄)₂SO₄, 2.93 g/L KH₂PO₄ and 7.31 g/L KH₂PO₄, 0.5 g/L NaCl, 0.5 g/L MgSO₄·7H₂O, 30 g/L sucrose or 30 g/L glycerol, 1 mL/L vitamin solution, 100 μL/L molybdate solution, and 1 mL/L selenium solution with the same composition as described above. As specified in the respective examples, 20 g/L lactose, 20 g/L 2′FL, 20 g/L 3-FL, 20 g/L 3′SL, 20 g/L LacNAc and/or 20 g/L LNB were additionally added to the medium as acceptor(s).

Complex medium was sterilized by autoclaving (121° C., 21 min) and minimal medium by filtration (0.22 μm Sartorius). When necessary, the medium was made selective by adding an antibiotic: e.g., chloramphenicol (20 mg/L), carbenicillin (100 mg/L), spectinomycin (40 mg/L) and/or kanamycin (50 mg/L).

Plasmids

pKD46 (Red helper plasmid, Ampicillin resistance), pKD3 (contains an FRT-flanked chloramphenicol resistance (cat) gene), pKD4 (contains an FRT-flanked kanamycin resistance (kan) gene), and pCP20 (expresses FLP recombinase activity) plasmids were obtained from Prof. R. Cunin (Vrije Universiteit Brussel, Belgium in 2007). Plasmids were maintained in the host E. coli DH5alpha (F⁻, phi80diacZΔM15, Δ(iacZYA-argF) U169, deoR, recA1, endA1, hsdR17(rk⁻, mk⁺), phoA, supE44, lambda⁻, thi-1, gyrA96, relA1) bought from Invitrogen.

Strains and Mutations

Escherichia coli K12 MG1655 [λ⁻, F⁻, rph-1] was obtained from the Coli Genetic Stock Center (US), CGSC Strain #: 7740, in March 2007. Gene disruptions, gene introductions and gene replacements were performed using the technique published by Datsenko and Wanner (PNAS 97 (2000), 6640-6645). This technique is based on antibiotic selection after homologous recombination performed by lambda Red recombinase. Subsequent catalysis of a flippase recombinase ensures removal of the antibiotic selection cassette in the final production strain. Transformants carrying a Red helper plasmid pKD46 were grown in 10 mL LB media with ampicillin, (100 mg/L) and L-arabinose (10 mM) at 30° C. to an OD₆₀₀ nm of 0.6. The cells were made electrocompetent by washing them with 50 mL of ice-cold water, a first time, and with 1 mL ice cold water, a second time. Then, the cells were resuspended in 50 μL of ice-cold water. Electroporation was done with 50 μL of cells and 10-100 ng of linear double-stranded-DNA product by using a GENE PULSER™ (BioRad) (600Ω, 25 μFD, and 250 volts). After electroporation, cells were added to 1 mL LB media incubated 1 h at 37° C., and finally spread onto LB-agar containing 25 mg/L of chloramphenicol or 50 mg/L of kanamycin to select antibiotic resistant transformants. The selected mutants were verified by PCR with primers upstream and downstream of the modified region and were grown in LB-agar at 42° C. for the loss of the helper plasmid. The mutants were tested for ampicillin sensitivity. The linear ds-DNA amplicons were obtained by PCR using pKD3, pKD4 and their derivates as template. The primers used had a part of the sequence complementary to the template and another part complementary to the side on the chromosomal DNA where the recombination must take place. For the genomic knock-out, the region of homology was designed 50-nt upstream and 50-nt downstream of the start and stop codon of the gene of interest. For the genomic knock-in, the transcriptional starting point (+1) had to be respected. PCR products were PCR-purified, digested with DpnI, re-purified from an agarose gel, and suspended in elution buffer (5 mM Tris, pH 8.0). Selected mutants were transformed with pCP20 plasmid, which is an ampicillin and chloramphenicol resistant plasmid that shows temperature-sensitive replication and thermal induction of FLP synthesis. The ampicillin-resistant transformants were selected at 30° C., after which a few were colony purified in LB at 42° C. and then tested for loss of all antibiotic resistance and of the FLP helper plasmid. The gene knock-outs and knock-ins are checked with control primers.

In an example for GDP-fucose production, the mutant strain was derived from E. coli K12 MG1655 comprising knock-outs of the E. coli wcaJ and thyA genes and genomic knock-ins of constitutive transcriptional units containing a sucrose transporter like e.g., CscB from E. coli W (UniProt ID E0IXR1), a fructose kinase like e.g., Frk originating from Zymomonas mobilis (UniProt ID Q03417) and a sucrose phosphorylase like BaSP originating from Bifidobacterium adolescentis (UniProt ID A0ZZH6). For production of fucosylated oligosaccharides, the mutant GDP-fucose production strain was additionally modified with expression plasmids comprising constitutive transcriptional units for an alpha-1,2-fucosyltransferase like e.g., HpFutC from H. pylori (GenBank: AAD29863.1) and/or an alpha-1,3-fucosyltransferase like e.g., HpFucT from H. pylori (UniProt ID 030511) and with a constitutive transcriptional unit for a selection marker like e.g., the E. coli thyA (UniProt ID P0A884). The constitutive transcriptional units of the fucosyltransferase genes could also be present in the mutant E. coli strain via genomic knock-ins. GDP-fucose production can further be optimized in the mutant E. coli strain by genomic knock-outs of the E. coli genes comprising glgC, agp, pfkA, pfkB, pgi, arcA, iclR, pgi and ion as described in WO 2016075243 and WO 2012007481. GDP-fucose production can additionally be optimized comprising genomic knock-ins of constitutive transcriptional units for a mannose-6-phosphate isomerase like e.g., manA from E. coli (UniProt ID P00946), a phosphomannomutase like e.g., manB from E. coli (UniProt ID P24175), a mannose-1-phosphate guanylyltransferase like e.g., manC from E. coli (UniProt ID P24174), a GDP-mannose 4,6-dehydratase like e.g., gmd from E. coli (UniProt ID P0AC88) and a GDP-L-fucose synthase like e.g., fcl from E. coli (UniProt ID P32055). GDP-fucose production can also be obtained by genomic knock-outs of the E. coli fucK and fucI genes and genomic knock-ins of constitutive transcriptional units containing a fucose permease like e.g., fucP from E. coli (UniProt ID P11551) and a bifunctional fucose kinase/fucose-1-phosphate guanylyltransferase like e.g., fkp from Bacteroides fragilis (UniProt ID SUV40286.1). If the mutant strains producing GDP-fucose were intended to make fucosylated lactose structures comprising 2′FL, 3-FL and DiFL, the strains were additionally modified with genomic knock-outs of the E. coli LacZ, LacY and LacA genes and with a genomic knock-in of a constitutive transcriptional unit for a lactose permease like e.g., the E. coli LacY (UniProt ID P02920) Alternatively, and/or additionally, production of GDP-fucose and/or fucosylated structures can further be optimized in the mutant E. coli strains with genomic knock-ins of a constitutive transcriptional unit comprising a membrane transporter protein like e.g., MdfA from Cronobacter muytjensii (UniProt ID AOA2T7ANQ9), MdfA from Citrobacter youngae (UniProt ID D4BC23), MdfA from E. coli (UniProt ID POAEY8), MdfA from Yokenella regensburgei (UniProt ID G9Z5F4), iceT from E. coli (UniProt ID A0A024L207) or iceT from Citrobacter youngae (UniProt ID D4B8A6).

In an example for sialic acid production, the mutant strain was derived from E. coli K12 MG1655 comprising genomic knock-ins of constitutive transcriptional units containing one or more copies of a glucosamine 6-phosphate N-acetyltransferase like e.g., GNA1 from Saccharomyces cerevisiae (UniProt ID P43577), an N-acetylglucosamine 2-epimerase like e.g., AGE from Bacteroides ovatus (UniProt ID A7LVG6) and an N-acetylneuraminate synthase like e.g., from Neisseria meningitidis (UniProt ID E0NCD4) or Campylobacter jejuni (UniProt ID Q93MP9).

Alternatively, and/or additionally, sialic acid production can be obtained by genomic knock-ins of constitutive transcriptional units containing an UDP-N-acetylglucosamine 2-epimerase like e.g., NeuC from C. jejuni (UniProt ID Q93MP8) and an N-acetylneuraminate synthase like e.g., from Neisseria meningitidis (UniProt ID E0NCD4) or Campylobacter jejuni (UniProt ID Q93MP9).

Alternatively, and/or additionally, sialic acid production can be obtained by genomic knock-ins of constitutive transcriptional units containing a phosphoglucosamine mutase like e.g., glmM from E. coli (UniProt ID P31120), an N-acetylglucosamine-1-phosphate uridyltransferase/glucosamine-1-phosphate acetyltransferase like e.g., glmU from E. coli (UniProt ID P0ACC7), an UDP-N-acetylglucosamine 2-epimerase like e.g., NeuC from C. jejuni (UniProt ID Q93MP8) and an N-acetylneuraminate synthase like e.g., from Neisseria meningitidis (UniProt ID E0NCD4) or Campylobacter jejuni (UniProt ID Q93MP9).

Alternatively, and/or additionally, sialic acid production can be obtained by genomic knock-ins of constitutive transcriptional units containing a bifunctional UDP-GlcNAc 2-epimerase/N-acetylmannosamine kinase like e.g., from Mus musculus (strain C57BL/6J) (UniProt ID Q91WG8), an N-acylneuraminate-9-phosphate synthetase like e.g., from Pseudomonas sp. UW4 (UniProt ID K9NPH9) and an N-acylneuraminate-9-phosphatase like e.g., from Candidatus magnetomorum sp. HK-1 (UniProt ID KPA15328.1) or from Bacteroides thetaiotaomicron (UniProt ID Q8A712).

Alternatively, and/or additionally, sialic acid production can be obtained by genomic knock-ins of constitutive transcriptional units containing a phosphoglucosamine mutase like e.g., glmM from E. coli (UniProt ID P31120), an N-acetylglucosamine-1-phosphate uridyltransferase/glucosamine-1-phosphate acetyltransferase like e.g., glmU from E. coli (UniProt ID P0ACC7), a bifunctional UDP-GlcNAc 2-epimerase/N-acetylmannosamine kinase like e.g., from M. musculus (strain C57BL/6J) (UniProt ID Q91WG8), an N-acylneuraminate-9-phosphate synthetase like e.g., from Pseudomonas sp. UW4 (UniProt ID K9NPH9) and an N-acylneuraminate-9-phosphatase like e.g., from Candidatus magnetomorum sp. HK-1 (UniProt ID KPA15328.1) or from Bacteroides thetaiotaomicron (UniProt ID Q8A712).

Sialic acid production can further be optimized in the mutant E. coli strain with genomic knock-outs of the E. coli genes comprising any one or more of nagA, nagB, nagC, nagD, nagE, nanA, nanE, nanK, manX, manY and manZ as described in WO 2018122225, and/or genomic knock-outs of the E. coli genes comprising any one or more of nanT, poxB, ldhA, adhE, aldB, pflA, pflC, ybiY, ackA and/or pta and with genomic knock-ins of constitutive transcriptional units comprising one or more copies of an L-glutamine-D-fructose-6-phosphate aminotransferase like e.g., the mutant glmS*54 from E. coli (differing from the wild-type E. coli glmS, having UniProt ID P17169, by an A39T, an R250C and an G472S mutation as described by Deng et al. (Biochimie 88, 419-29 (2006)), preferably a phosphatase like e.g., the E. coli genes comprising aphA, Cof, HisB, OtsB, SurE, Yaed, YcjU, YedP, YfbT, YidA, YigB, YihX, YniC, YqaB, YrbL, AppA, Gph, SerB, YbhA, YbiV, YbjL, Yfb, YieH, YjgL, YjjG, YrfG and YbiU or PsMupP from Pseudomonas putida, ScDOG1 from S. cerevisiae or BsAraL from Bacillus subtilis as described in WO 2018122225 and an acetyl-CoA synthetase like e.g., acs from E. coli (UniProt ID P27550).

For sialylated oligosaccharide production, the sialic acid production strains were further modified to express an N-acylneuraminate cytidylyltransferase like e.g., the NeuA enzyme from C. jejuni (UniProt ID Q93MP7), the NeuA enzyme from Haemophilus influenzae (GenBank NO. AGV11798.1) or the NeuA enzyme from Pasteurella multocida (GenBank NO. AMK07891.1) and to express one or more copies of a beta-galactoside alpha-2,3-sialyltransferase like e.g., PmultST3 from P. multocida (UniProt ID Q9CLP3) or a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity, NmeniST3 from N. meningitidis (GenBank NO. ARC07984.1) or PmultST2 from P. multocida subsp. multocida str. Pm70 (GenBank NO. AAK02592.1), a beta-galactoside alpha-2,6-sialyltransferase like e.g., PdST6 from Photobacterium damselae (UniProt ID 066375) or a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity or P-JT-ISH-224-ST6 from Photobacterium sp. JT-ISH-224 (UniProt ID A8QYL1) or a P-JT-ISH-224-ST6-like polypeptide comprising amino acid residues 18 to 514 of UniProt ID A8QYL1 having beta-galactoside alpha-2,6-sialyltransferase activity, and/or an alpha-2,8-sialyltransferase like e.g., from M. musculus (UniProt ID Q64689). Constitutive transcriptional units of the N-acylneuraminate cytidylyltransferase and the sialyltransferases can be delivered to the mutant strain either via genomic knock-in or via an expression plasmid. If the mutant strains producing sialic acid and CMP-sialic acid were intended to make sialylated lactose structures, the strains were additionally modified with genomic knock-outs of the E. coli LacZ, LacY and LacA genes and with a genomic knock-in of a constitutive transcriptional unit for a lactose permease like e.g., E. coli LacY (UniProt ID P02920).

Alternatively, and/or additionally, sialic acid and/or sialylated oligosaccharide production can further be optimized in the mutant E. coli strains with a genomic knock-in of a constitutive transcriptional unit comprising a membrane transporter protein like e.g., a sialic acid transporter like e.g., nanT from E. coli K-12 MG1655 (UniProt ID P41036), nanT from E. coli O6:H1 (UniProt ID Q8FD59), nanT from E. coli O157:H7 (UniProt ID Q8X9G8) or nanT from E. albertii (UniProt ID B 1EFH1) or a porter like e.g., EntS from E. coli (UniProt ID P24077), EntS from Kluyvera ascorbata (UniProt ID A0A378GQ13) or EntS from Salmonella enterica subsp. arizonae (UniProt ID AOA6Y2K4E8), MdfA from Cronobacter muytjensii (UniProt ID AOA2T7ANQ9), MdfA from Citrobacter youngae (UniProt ID D4BC23), MdfA from E. coli (UniProt ID POAEY8), MdfA from Yokenella regensburgei (UniProt ID G9Z5F4), iceT from E. coli (UniProt ID A0A024L207), iceT from Citrobacter youngae (UniProt ID D4B8A6), SetA from E. coli (UniProt ID P31675), SetB from E. coli (UniProt ID P33026) or SetC from E. coli (UniProt ID P31436) or an ABC transporter like e.g., oppF from E. coli (UniProt ID P77737), lmrA from Lactococcus lactis subsp. lactis bv. diacetylactis (UniProt ID AOA1VONEL4), or Blon 2475 from Bifidobacterium longum subsp. infantis (UniProt ID B7GPD4).

All mutant strains producing sialic acid, CMP-sialic acid and/or sialylated oligosaccharides could optionally be adapted for growth on sucrose via genomic knock-ins of constitutive transcriptional units containing a sucrose transporter like e.g., CscB from E. coli W (UniProt ID E0IXR1), a fructose kinase like e.g., Frk originating from Z. mobilis (UniProt ID Q03417) and a sucrose phosphorylase like e.g., BaSP from B. adolescentis (UniProt ID A0ZZH6).

In an example to produce lacto-N-triose (LNT-II, LN3, GlcNAc-b1,3-Gal-b1,4-Glc), the mutant strain was derived from E. coli K12 MG1655 and modified with knock-outs of the E. coli LacZ, LacY, LacA and nagB genes and with genomic knock-ins of constitutive transcriptional units for a lactose permease like e.g., LacY from E. coli (UniProt ID P02920) and a galactoside beta-1,3-N-acetylglucosaminyltransferase like e.g., LgtA from N. meningitidis (GenBank: AAM33849.1). For the production of lacto-N-tetraose (LNT, Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc), the LN3 producing strain is further modified with a constitutive transcriptional unit for an N-acetylglucosamine beta-1,3-galactosyltransferase like e.g., WbgO from E. coli 055:H7 (UniProt ID D3QY14) that can be delivered to the strain either via genomic knock-in or from an expression plasmid. For the production of lacto-N-neotetraose (LNnT, Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc), the LN3 producing strain is further modified with a constitutive transcriptional unit for an N-acetylglucosamine beta-1,4-galactosyltransferase like e.g., LgtB from Neisseria meningitidis (UniProt ID Q51116). Optionally, multiple copies of the LgtA, wbgO and/or LgtB genes could be added to the mutant E. coli strains. Also, LNT and/or LNnT production can be enhanced by improved UDP-GlcNAc production by modification of the strains with one or more genomic knock-ins of a constitutive transcriptional unit for an L-glutamine-D-fructose-6-phosphate aminotransferase like e.g., the mutant glmS*54 from E. coli (differing from the wild-type E. coli glmS protein, having UniProt ID P17169, by an A39T, an R250C and an G472S mutation as described by Deng et al. (Biochimie 2006, 88: 419-429). In addition, the strains can optionally be modified for enhanced UDP-galactose production with genomic knock-outs of the E. coli ushA, galT, ldhA and agp genes. The mutant E. coli strains can also optionally be adapted with a genomic knock-in of a constitutive transcriptional unit for an UDP-glucose-4-epimerase like e.g., galE from E. coli (UniProt ID P09147), a phosphoglucosamine mutase like e.g., glmM from E. coli (UniProt ID P31120) and an N-acetylglucosamine-1-phosphate uridylyltransferase/glucosamine-1-phosphate acetyltransferase like e.g., glmU from E. coli (UniProt ID P0ACC7). The mutant strains could also optionally be adapted for growth on sucrose via genomic knock-ins of constitutive transcriptional units containing a sucrose transporter like e.g., CscB from E. coli W (UniProt ID E0IXR1), a fructose kinase like e.g., Frk originating from Z. mobilis (UniProt ID Q03417) and a sucrose phosphorylase like e.g., BaSP from B. adolescentis (UniProt ID A0ZZH6). Alternatively, and/or additionally, production of LN3, LNT, LNnT and oligosaccharides derived thereof can further be optimized in the mutant E. coli strains with a genomic knock-in of a constitutive transcriptional unit comprising a membrane transporter protein like e.g., MdfA from Cronobacter muytjensii (UniProt ID AOA2T7ANQ9), MdfA from Citrobacter youngae (UniProt ID D4BC23), MdfA from E. coli (UniProt ID POAEY8), MdfA from Yokenella regensburgei (UniProt ID G9Z5F4), iceT from E. coli (UniProt ID A0A024L207) or iceT from Citrobacter youngae (UniProt ID D4B8A6).

Preferably, but not necessarily, any one or more of the glycosyltransferases, the proteins involved in nucleotide-activated sugar synthesis and/or membrane transporter proteins were N- and/or C-terminally fused to a solubility enhancer tag like e.g., a SUMO-tag, an MBP-tag, His, FLAG®, Strep-II, Halo-tag, NusA, thioredoxin, GST and/or the Fh8-tag to enhance their solubility (Costa et al., Front. Microbiol. 2014, doi.org/10.3389/fmicb.2014.00063; Fox et al., Protein Sci. 2001, 10(3), 622-630; Jia and Jeaon, Open Biol. 2016, 6: 160196). Optionally, the mutant E. coli strains were modified with a genomic knock-in of a constitutive transcriptional unit encoding a chaperone protein like e.g., DnaK, DnaJ, GrpE, or the GroEL/ES chaperonin system (Baneyx F., Palumbo J. L. (2003) Improving Heterologous Protein Folding via Molecular Chaperone and Foldase Co-Expression. In: Vaillancourt P. E. (eds) E. coli Gene Expression Protocols. Methods in Molecular Biology™, vol 205. Humana Press).

Optionally, the mutant E. coli strains are modified to create a glycominimized E. coli strain comprising genomic knock-out of any one or more of non-essential glycosyltransferase genes comprising pgaC, pgaD, rfe, rffT, rffM, bcsA, bcsB, bcsC, wcaA, wcaC, wcaE, wcaI, wcaJ, wcaL, waaH, waaF, waaC, waaU, waaZ, waaJ, waaO, waaB, waaS, waaG, waaQ, wbbI, arnC, arnT, yfdH, wbbK, opgG, opgH, ycjM, glgA, glgB, malQ, otsA and yaiP.

All constitutive promoters, UTRs and terminator sequences originated from the libraries described by Cambray et al. (Nucleic Acids Res. 2013, 41(9), 5139-5148), De Mey et al. (BMC Biotechnol. 2007, 4(34), 1-14), Dunn et al. (Nucleic Acids Res. 1980, 8(10), 2119-2132), Kim and Lee (FEBS Letters 1997, 407(3), 353-356) and Mutalik et al. (Nat. Methods 2013, No. 10, 354-360).

All genes were ordered synthetically at Twist Bioscience (twistbioscience.com) or IDT (eu.idtdna.com) and the codon usage was adapted using the tools of the supplier.

All strains were stored in cryovials at −80° C. (overnight LB culture mixed in a 1:1 ratio with 70% glycerol).

Cultivation Conditions

A preculture of 96-well microtiter plate experiments was started from a cryovial, in 150 μL LB and was incubated overnight at 37° C. on an orbital shaker at 800 rpm. This culture was used as inoculum for a 96-well square microtiter plate, with 400 μL minimal medium by diluting 400×. These final 96-well culture plates were then incubated at 37° C. on an orbital shaker at 800 rpm for 72 h, or shorter, or longer. To measure sugar concentrations at the end of the cultivation experiment whole broth samples were taken from each well by boiling the culture broth for 15 min at 60° C. before spinning down the cells (=average of intra- and extracellular sugar concentrations).

A preculture for the bioreactor was started from an entire 1 mL cryovial of a certain strain, inoculated in 250 mL or 500 mL minimal medium in a 1 L or 2.5 L shake flask and incubated for 24 h at 37° C. on an orbital shaker at 200 rpm. A 5 L bioreactor was then inoculated (250 mL inoculum in 2 L batch medium); the process was controlled by MFCS control software (Sartorius Stedim Biotech, Melsungen, Germany). Culturing conditions were set to 37° C., and maximal stirring; pressure gas flow rates were dependent on the strain and bioreactor. The pH was controlled at 6.8 using 0.5 M H₂SO₄ and 20% NH₄OH. The exhaust gas was cooled. 10% solution of silicone antifoaming agent was added when foaming raised during the fermentation.

Optical Density

Cell density of the cultures was frequently monitored by measuring optical density at 600 nm (Implen Nanophotometer NP80, Westburg, Belgium or with a Spark 10M microplate reader, Tecan, Switzerland).

Analytical Analysis

Standards such as but not limited to sucrose, lactose, LacNAc, lacto-N-biose (LNB), fucosylated LacNAc (2′FLacNAc, 3-FLacNAc), sialylated LacNAc, (3′SLacNAc, 6′SLacNAc), fucosylated LNB (2′FLNB, 4′FLNB), lacto-N-triose II (LN3), lacto-N-tetraose (LNT), lacto-N-neo-tetraose (LNnT), LNFP-I, LNFP-II, LNFP-III, LNFP-V, LNFP-VI, LSTa and LSTc were purchased from Carbosynth (UK), Elicityl (France) and IsoSep (Sweden). Other compounds were analyzed with in-house made standards.

Neutral oligosaccharides were analyzed on a Waters Acquity H-class UPLC with Evaporative Light Scattering Detector (ELSD) or a Refractive Index (RI) detection. A volume of 0.7 μL sample was injected on a Waters Acquity UPLC BEH Amide column (2.1×100 mm; 130 Å; 1.7 μm) column with an Acquity UPLC BEH Amide VanGuard column, 130 Å, 2.1×5 mm. The column temperature was 50° C. The mobile phase comprised a ¼ water and ¾ acetonitrile solution to which 0.2% triethylamine was added. The method was isocratic with a flow of 0.130 mL/min. The ELS detector had a drift tube temperature of 50° C. and the N2 gas pressure was 50 psi, the gain 200 and the data rate 10 pps. The temperature of the RI detector was set at 35° C.

Sialylated oligosaccharides were analyzed on a Waters Acquity H-class UPLC with Refractive Index (RI) detection. A volume of 0. 5 μL sample was injected on a Waters Acquity UPLC BEH Amide column (2.1×100 mm; 130 Å; 1.7 μm). The column temperature was 50° C. The mobile phase comprised a mixture of 70% acetonitrile, 26% ammonium acetate buffer (150 mM) and 4% methanol to which 0.05% pyrrolidine was added. The method was isocratic with a flow of 0.150 mL/min. The temperature of the RI detector was set at 35° C.

Both neutral and sialylated sugars were analyzed on a Waters Acquity H-class UPLC with Refractive Index (RI) detection. A volume of 0.5 μL sample was injected on a Waters Acquity UPLC BEH Amide column (2.1×100 mm; 130 Å; 1.7 μm). The column temperature was 50° C. The mobile phase comprised a mixture of 72% acetonitrile and 28% ammonium acetate buffer (100 mM) to which 0.1% triethylamine was added. The method was isocratic with a flow of 0.260 mL/min. The temperature of the RI detector was set at 35° C.

For analysis on a mass spectrometer, a Waters Xevo TQ-MS with Electron Spray Ionization (ESI) was used with a desolvation temperature of 450° C., a nitrogen desolvation gas flow of 650 L/h and a cone voltage of 20 V. The MS was operated in selected ion monitoring (SIM) in negative mode for all oligosaccharides. Separation was performed on a Waters Acquity UPLC with a Thermo Hypercarb column (2.1×100 mm; 3 μm) on 35° C. A gradient was used wherein eluent A was ultrapure water with 0.1% formic acid and wherein eluent B was acetonitrile with 0.1% formic acid. The oligosaccharides were separated in 55 min using the following gradient: an initial increase from 2% to 12% of eluent B over 21 min, a second increase from 12% to 40% of eluent B over 11 min and a third increase from 40% to 100% of eluent B over 5 min. As a washing step 100% of eluent B was used for 5 min. For column equilibration, the initial condition of 2% of eluent B was restored in 1 min and maintained for 12 min.

Both neutral and sialylated sugars at low concentrations (below 50 mg/L) were analyzed on a Dionex HPAEC system with pulsed amperometric detection (PAD). A volume of 5 μL of sample was injected on a Dionex CarboPac PA200 column 4×250 mm with a Dionex CarboPac PA200 guard column 4×50 mm. The column temperature was set to 30° C. A gradient was used wherein eluent A was deionized water, wherein eluent B was 200 mM Sodium hydroxide and wherein eluent C was 500 mM Sodium acetate. The oligosaccharides were separated in 60 min while maintaining a constant ratio of 25% of eluent B using the following gradient: an initial isocratic step maintained for 10 min of 75% of eluent A, an initial increase from 0% to 4% of eluent C over 8 min, a second isocratic step maintained for 6 min of 71% of eluent A and 4% of eluent C, a second increase from 4% to 12% of eluent C over 2.6 min, a third isocratic step maintained for 3.4 min of 63% of eluent A and 12% of eluent C and a third increase from 12% to 48% of eluent C over 5 min. As a washing step 48% of eluent C was used for 3 min. For column equilibration, the initial condition of 75% of eluent A and 0% of eluent C was restored in 1 min and maintained for 11 min. The applied flow was 0.5 mL/min.

Example 2. Materials and Methods Saccharomyces cerevisiae

Media

Strains were grown on Synthetic Defined yeast medium with Complete Supplement Mixture (SD CSM) or CSM drop-out (SD CSM-Ura, SD CSM-Trp, SD CSM-His) containing 6.7 g/L Yeast Nitrogen Base without amino acids (YNB w/o AA, Difco), 20 g/L agar (Difco) (solid cultures), 22 g/L glucose monohydrate or 20 g/L lactose, 20 g/L 2′FL, 20 g/L 3-FL, 20 g/L 3′SL, 20 g/L 6′SL, 20 g/L LacNAc and/or 20 g/L LNB and 0.79 g/L CSM or 0.77 g/L CSM-Ura, 0.77 g/L CSM-Trp, or 0.77 g/L CSM-His (MP Biomedicals).

Strains

S. cerevisiae BY4742 created by Brachmann et al. (Yeast (1998) 14:115-32) was used, available in the Euroscarf culture collection. All mutant strains were created by homologous recombination or plasmid transformation using the method of Gietz (Yeast 11:355-360, 1995).

Plasmids

In an example to produce GDP-fucose, a yeast expression plasmid like e.g., p2a_2μ_Fuc (Chan 2013, Plasmid 70, 2-17) was used for expression of foreign genes in S. cerevisiae. This plasmid contained an ampicillin resistance gene and a bacterial origin of replication to allow for selection and maintenance in E. coli and the 2μ yeast ori and the Ura3 selection marker for selection and maintenance in yeast. This plasmid further contained constitutive transcriptional units for a lactose permease like e.g., LAC12 from Kluyveromyces lactis (UniProt ID P07921), a GDP-mannose 4,6-dehydratase like e.g., gmd from E. coli (UniProt ID P0AC88) and a GDP-L-fucose synthase like e.g., fcl from E. coli (UniProt ID P32055). The yeast expression plasmid p2a_2μ_Fuc2 was used as an alternative expression plasmid of the p2a_2μ_Fuc plasmid comprising next to the ampicillin resistance gene, the bacterial ori, the 2μ yeast ori and the Ura3 selection marker constitutive transcriptional units for a lactose permease like e.g., LAC12 from K. lactis (UniProt ID P07921), a fucose permease like e.g., fucP from E. coli (UniProt ID P11551) and a bifunctional fucose kinase/fucose-1-phosphate guanylyltransferase like e.g., fkp from B. fragilis (UniProt ID SUV40286.1). To further produce fucosylated oligosaccharides, the p2a_2μ_Fuc and its variant the p2a_2μ_Fuc2, additionally contained a constitutive transcriptional unit for an alpha-1,2-fucosyltransferase like e.g., HpFutC from H. pylori (GenBank: AAD29863.1).

In an example to produce UDP-galactose, a yeast expression plasmid was derived from the pRS420-plasmid series (Christianson et al., 1992, Gene 110: 119-122) containing the HIS3 selection marker and a constitutive transcriptional unit for an UDP-glucose-4-epimerase like e.g., galE from E. coli (UniProt ID P09147). To produce LN3 and LNT, this plasmid was further modified with constitutive transcriptional units for a lactose permease like e.g., LAC12 from K. lactis (UniProt ID P07921), a galactoside beta-1,3-N-acetylglucosaminyltransferase like e.g., lgtA from N. meningitidis (GenBank: AAM33849.1) and an N-acetylglucosamine beta-1,3-galactosyltransferase like e.g., WbgO from E. coli O55:H7 (UniProt ID D3QY14). To produce UDP-GalNAc, the plasmid was additionally modified with constitutive transcriptional units for an 4-epimerase like e.g., WbpP from Pseudomonas aeruginosa (UniProt ID Q8KN66) next to optional knock-ins for a phosphoglucosamine mutase like e.g., glmM from E. coli (UniProt ID P31120) and an N-acetylglucosamine-1-phosphate uridylyltransferase/glucosamine-1-phosphate acetyltransferase like e.g., glmU from E. coli (UniProt ID P0ACC7).

In an example to produce sialic acid and CMP-sialic acid, a yeast expression plasmid can be derived from the pRS420-plasmid series (Christianson et al., 1992, Gene 110: 119-122) containing the TRP1 selection marker and constitutive transcriptional units for one or more copies of an L-glutamine-D-fructose-6-phosphate aminotransferase like e.g., the mutant glmS*54 from E. coli (differing from the wild-type E. coli glmS, having UniProt ID P17169, by an A39T, an R250C and an G472S mutation as described by Deng et al. (Biochimie 88, 419-29 (2006)), a phosphatase like e.g., the E. coli genes comprising aphA, Cof, HisB, OtsB, SurE, Yaed, YcjU, YedP, YfbT, YidA, YigB, YihX, YniC, YqaB, YrbL, AppA, Gph, SerB, YbhA, YbiV, YbjL, Yfb, YieH, YjgL, YjjG, YrfG and YbiU or PsMupP from Pseudomonas putida, ScDOG1 from S. cerevisiae or BsAraL from Bacillus subtilis as described in WO 2018122225, an N-acetylglucosamine 2-epimerase like e.g., AGE from B. ovatus (UniProt ID A7LVG6), an N-acetylneuraminate synthase like e.g., from Neisseria meningitidis (UniProt ID E0NCD4) or Campylobacter jejuni (UniProt ID Q93MP9), and an N-acylneuraminate cytidylyltransferase like e.g., NeuA from C. jejuni (UniProt ID Q93MP7), NeuA from Haemophilus influenzae (GenBank No. AGV11798.1) or NeuA from Pasteurella multocida (GenBank No. AMK07891.1). Optionally, a constitutive transcriptional unit comprising one or more copies for a glucosamine 6-phosphate N-acetyltransferase like e.g., GNA1 from S. cerevisiae (UniProt ID P43577) was/were added as well. To produce sialylated oligosaccharides, the plasmid further comprised constitutive transcriptional units for a lactose permease like e.g., LAC12 from Kluyveromyces lactis (UniProt ID P07921), and one or more copies of a beta-galactoside alpha-2,3-sialyltransferase like e.g., PmultST3 from P. multocida (UniProt ID Q9CLP3) or a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity, NmeniST3 from N. meningitidis (GenBank No. ARC07984.1) or PmultST2 from P. multocida subsp. multocida str. Pm70 (GenBank No. AAK02592.1), a beta-galactoside alpha-2,6-sialyltransferase like e.g., PdST6 from Photobacterium damselae (UniProt ID 066375) or a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity or P-JT-ISH-224-ST6 from Photobacterium sp. JT-ISH-224 (UniProt ID A8QYL1) or a P-JT-ISH-224-ST6-like polypeptide comprising amino acid residues 18 to 514 of UniProt ID A8QYL1 having beta-galactoside alpha-2,6-sialyltransferase activity, and/or an alpha-2,8-sialyltransferase like e.g., from M. musculus (UniProt ID Q64689).

Preferably, but not necessarily, any one or more of the glycosyltransferases, the proteins involved in nucleotide-activated sugar synthesis and/or membrane transporter proteins were N- and/or C-terminally fused to a SUMOstar tag (e.g., obtained from pYSUMOstar, Life Sensors, Malvern, Pa.) to enhance their solubility.

Optionally, the mutant yeast strains were modified with a genomic knock-in of a constitutive transcriptional unit encoding a chaperone protein like e.g., Hsp31, Hsp32, Hsp33, Sno4, Kar2, Ssb1, Sse1, Sse2, Ssa1, Ssa2, Ssa3, Ssa4, Ssb2, Ecm10, Ssc1, Ssq1, Ssz1, Lhs1, Hsp82, Hsc82, Hsp78, Hsp104, Tcp1, Cct4, Cct8, Cct2, Cct3, Cct5, Cct6, or Cct7 (Gong et al., 2009, Mol. Syst. Biol. 5: 275).

Plasmids were maintained in the host E. coli DH5alpha (F⁻, phi80dlacZdeltaM15, delta(lacZYA-argF)U169, deoR, recA1, endA1, hsdR17(rk⁻, mk⁺), phoA, supE44, lambda⁻, thi-1, gyrA96, relA1) bought from Invitrogen.

Heterologous and Homologous Expression

Genes that needed to be expressed, be it from a plasmid or from the genome were synthetically synthetized with one of the following companies: DNA2.0, Gen9, IDT or Twist Bioscience. Expression could be further facilitated by optimizing the codon usage to the codon usage of the expression host. Genes were optimized using the tools of the supplier.

Cultivations Conditions

In general, yeast strains were initially grown on SD CSM plates to obtain single colonies. These plates were grown for 2-3 days at 30° C. Starting from a single colony, a preculture was grown over night in 5 mL at 30° C., shaking at 200 rpm. Subsequent 125 mL shake flask experiments were inoculated with 2% of this preculture, in 25 mL media. These shake flasks were incubated at 30° C. with an orbital shaking of 200 rpm.

Gene Expression Promoters

Genes were expressed using synthetic constitutive promoters, as described by Blazeck (Biotechnology and Bioengineering, Vol. 109, No. 11, 2012).

Example 3. Production of an Oligosaccharide Mixture Comprising 2′FL and DiFL with a Modified E. coli Host Using Lactose and 3-FL as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1). The novel strain was evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contained sucrose as carbon source and lactose and 3-FL as acceptors. Each strain was grown in four biological replicates in a 96-well plate. After 72 h of incubation, the culture broth was harvested, and the sugar mixtures were analyzed on UPLC. The experiment demonstrated the novel strain produced an oligosaccharide mixture comprising 2′FL and 2′,-3-fucosyllactose (DiFL) in whole broth samples.

Example 4. Production of an Oligosaccharide Mixture Comprising 2′FL, DiFL and 2′FLacNAc with a Modified E. coli Host Using Lactose and LacNAc as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1). The novel strain produces an oligosaccharide mixture comprising 2′FL, DiFL and 2′-fucosylated N-acetyllactosamine (2′FLacNAc) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and N-acetyllactosamine (Gal-b1,4-GlcNAc, LacNAc) as acceptors.

Example 5. Production of an Oligosaccharide Mixture Comprising 2′FL, 3-FL, DiFL, 2′FLacNAc, 3-FLacNAc and DiFLacNAc with a Modified E. coli Host Using Lactose and LacNAc as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1) and the H. pylori alpha-1,3-fucosyltransferase HpFucT (UniProt ID 030511). The novel strain produces an oligosaccharide mixture comprising 2′FL, 3-FL and fucosylated LacNAc (i.e., 2′FLacNAc and 3-FLacNAc) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and LacNAc as acceptors. Since the enzyme HpFutC (GenBank: AAD29863.1) also shows fucosyltransferase activity on 2′FL and the enzyme HpFucT (UniProt ID 030511) also shows fucosyltransferase activity on 2′FLacNAc the novel strain also produces DiFL and Di-FLacNAc in the oligosaccharide mixture.

Example 6. Production of an Oligosaccharide Mixture Comprising 3-FL and 3-FLacNAc with a Modified E. coli Host Using Lactose and LacNAc as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,3-fucosyltransferase HpFucT (UniProt ID 030511). The novel strain produces an oligosaccharide mixture comprising 3-FL and 3-fucosylated N-acetyllactosamine (3′FLacNAc) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and LacNAc as acceptors.

Example 7. Production of an Oligosaccharide Mixture Comprising 2′FL, DiFL and 2′FLNB with a Modified E. coli Host Using Lactose and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1). The novel strain produces an oligosaccharide mixture comprising 2′FL, DiFL and 2′-fucosylated lacto-N-biose (2′FLNB) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and lacto-N-biose (Gal-b1,3-GlcNAc, LNB) as acceptors.

Example 8. Production of an Oligosaccharide Mixture Comprising 2′FL, 3-FL, DiFL, 2′FLNB, 4-FLNB and DiFLNB with a Modified E. coli Host Using Lactose and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1) and the H. pylori alpha-1,3-fucosyltransferase HpFucT (UniProt ID 030511). Since lactose and LNB are suitable acceptors for both H. pylori fucosyltransferases, the novel strain produces an oligosaccharide mixture comprising 2′FL, 3-FL and fucosylated LNB (i.e., 2′FLNB and 4-FLNB) in whole broth samples when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and LNB as acceptors. Since the enzyme HpFutC (GenBank: AAD29863.1) also shows fucosyltransferase activity on 2′FL and the enzyme HpFucT (UniProt ID 030511) also shows fucosyltransferase activity on 2′FLNB the novel strain also produces DiFL and difucosylated LNB (DiFLNB) in the oligosaccharide mixture.

Example 9. Production of an Oligosaccharide Mixture Comprising 3-FL and 4-FLNB with a Modified E. coli Host Using Lactose and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,3-fucosyltransferase HpFucT (UniProt ID 030511). The novel strain produces an oligosaccharide mixture comprising 3-FL and 4-fucosylated lacto-N-biose (4-FLNB) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and LNB as acceptors.

Example 10. Production of an Oligosaccharide Mixture Comprising 2′FLacNAc and 2′FLNB with a Modified E. coli Host Using LacNAc and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1). The novel strain produces an oligosaccharide mixture comprising 2′FLacNAc and 2′FLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and LacNAc and LNB as acceptors.

Example 11. Production of an Oligosaccharide Mixture Comprising 3′FLacNAc and 4-FLNB with a Modified E. coli Host Using LacNAc and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,3-fucosyltransferase HpFucT (UniProt ID 030511). The novel strain produces an oligosaccharide mixture comprising 3-FLacNAc and 4-FLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and LacNAc and LNB as acceptors.

Example 12. Production of an Oligosaccharide Mixture Comprising 2′FLacNAc, 3-FLacNAc, DiFLacNAc, 2′FLNB, 4-FLNB and DiFLNB with a Modified E. coli Host Using LacNAc and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1) and the H. pylori alpha-1,3-fucosyltransferase HpFucT (UniProt ID 030511). The novel strain produces an oligosaccharide mixture comprising 2′FLacNAc, 3-FLacNAc, DiFLacNAc, 2′FLNB, 4-FLNB and DiFLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and LacNAc and LNB as acceptors.

Example 13. Production of an Oligosaccharide Mixture Comprising 2′FL, DiFL, 2′FLacNAc and 2′FLNB with a Modified E. coli Host Using Lactose, LacNAc and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1). The novel strain produces an oligosaccharide mixture comprising 2′FL, DiFL, 2′FLacNAc and 2′FLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose, LacNAc and LNB as acceptors.

Example 14. Production of an Oligosaccharide Mixture Comprising 3-FL, 3′FLacNAc and 4-FLNB with a Modified E. coli Host Using Lactose, LacNAc and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing a constitutive transcriptional unit for the H. pylori alpha-1,3-fucosyltransferase HpFucT (UniProt ID 030511). The novel strain produces an oligosaccharide mixture comprising 3-FL, 3-FLacNAc and 4-FLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose, LacNAc and LNB as acceptors.

Example 15. Production of an Oligosaccharide Mixture Comprising 2′FL, 3-FL, DiFL, 2′FLacNAc, 3-FLacNAc, DiFLacNAc, 2′FLNB, 4-FLNB and DiFLNB with a Modified E. coli Host Using Lactose, LacNAc and LNB as Acceptors

An E. coli K12 strain modified for GDP-fucose production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for the H. pylori alpha-1,2-fucosyltransferase HpFutC (GenBank: AAD29863.1) and the H. pylori alpha-1,3-fucosyltransferase HpFucT (UniProt ID 030511). The novel strain produces an oligosaccharide mixture comprising 2′FL, 3-FL, DiFL, 2′FLacNAc, 3-FLacNAc, DiFLacNAc, 2′FLNB, 4-FLNB and DiFLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose, LacNAc and LNB as acceptors.

Example 16. Production of an Oligosaccharide Mixture Comprising 3′SL and 3′SLacNAc with a Modified E. coli Host Using Lactose and LacNAc as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity and the N-acylneuraminate cytidylyltransferase (NeuA) from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 3′SL and sialylated LacNAc (3′SLacNAc) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose and LacNAc as acceptors.

Example 17. Production of an Oligosaccharide Mixture Comprising 3′SL, 6′SL, 3′SLacNAc and 6′SLacNAc with a Modified E. coli Host Using Lactose and LacNAc as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity, a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity and the N-acylneuraminate cytidylyltransferase (NeuA) from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 3′SL, 6′SL and sialylated LacNAc (i.e., 3′SLacNAc and 6′SLacNAc) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose and LacNAc as acceptors.

Example 18. Production of an Oligosaccharide Mixture Comprising 6′SL and 6′SLacNAc with a Modified E. coli Host Using Lactose and LacNAc as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 6′SL and sialylated LacNAc (6′SLacNAc) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose and LacNAc as acceptors.

Example 19. Production of an Oligosaccharide Mixture Comprising 3′SL and 3′SLNB with a Modified E. coli Host Using Lactose and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 3′SL and sialylated LNB (3′SLNB) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose and LNB as acceptors.

Example 20. Production of an Oligosaccharide Mixture Comprising 3′SL, 6′SL, 3′SLNB and 6′SLNB with a Modified E. coli Host Using Lactose and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity, a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 3′SL, 6′SL and sialylated LNB (i.e., 3′SLNB and 6′SLNB) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose and LNB as acceptors.

Example 21. Production of an Oligosaccharide Mixture Comprising 6′SL and 6′SLNB with a Modified E. coli Host Using Lactose and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 6′SL and sialylated LNB (6′SLNB) in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose and LNB as acceptors.

Example 22. Production of an Oligosaccharide Mixture Comprising 3′SLacNAc and 3′SLNB with a Modified E. coli Host Using LacNAc and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 3′SLacNAc and 3′SLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and LacNAc and LNB as acceptors.

Example 23. Production of an Oligosaccharide Mixture Comprising 6′SLacNAc and 6′SLNB with a Modified E. coli Host Using LacNAc and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 6′SLacNAc and 6′SLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and LacNAc and LNB as acceptors.

Example 24. Production of an Oligosaccharide Mixture Comprising 3′SLacNAc, 6′SLacNAc, 3′SLNB and 6′SLNB with a Modified E. coli Host Using LacNAc and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity, a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 3′SLacNAc, 6′SLacNAc, 3′SLNB and 6′SLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and LacNAc and LNB as acceptors.

Example 25. Production of an Oligosaccharide Mixture Comprising 3′SL, 3′SLacNAc and 3′SLNB with a Modified E. coli Host Using Lactose, LacNAc and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 3′SL, 3′SLacNAc and 3′SLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose, LacNAc and LNB as acceptors.

Example 26. Production of an Oligosaccharide Mixture Comprising 6′SL, 6′SLacNAc and 6′SLNB with a Modified E. coli Host Using Lactose, LacNAc and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 6′SL, 6′SLacNAc and 6′SLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose, LacNAc and LNB as acceptors.

Example 27. Production of an Oligosaccharide Mixture Comprising 3′SL, 6′SL, 3′SLacNAc, 6′SLacNAc, 3′SLNB and 6′SLNB with a Modified E. coli Host Using Lactose, LacNAc and LNB as Acceptors

An E. coli K12 strain modified for sialic acid production as described in Example 1 was transformed with a plasmid expressing constitutive transcriptional units for a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity, a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity and NeuA from P. multocida (GenBank: AMK07891.1). The novel strain produces an oligosaccharide mixture comprising 3′SL, 6′SL, 3′SLacNAc, 6′SLacNAc, 3′SLNB and 6′SLNB in whole broth samples, when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose, LacNAc and LNB as acceptors.

Example 28. Production of an Oligosaccharide Mixture Comprising, 2′FL, DiFL, 2′FLacNAc, LN3, LNT and LNFP-I with a Modified E. coli Host

An E. coli strain modified for GDP-fucose production as described in Example 1 was further adapted for lacto-N-triose (LN3, LNT-II, GlcNAc-b1,3-Gal-b1,4-Glc) and LNT (Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc) production by genomic knock-ins of constitutive transcriptional units for the mutant glmS*54 from E. coli (differing from the wild-type E. coli glmS, having UniProt ID P17169, by an A39T, an R250C and an G472S mutation), the galactoside beta-1,3-N-acetylglucosaminyltransferase (LgtA) from N. meningitidis (UniProt ID Q9JXQ6) and the N-acetylglucosamine beta-1,3-galactosyltransferase (WbgO) from E. coli 055:H7 (UniProt ID D3QY14). In a next step, the novel strain was further transformed with an expression plasmid containing a constitutive transcriptional unit for the α-1,2-fucosyltransferase from H. pylori HpFutC (GenBank: AAD29863.1). The novel strain produces an oligosaccharide mixture comprising 2′FL, DiFL, 2′FLacNAc, LN3, LNT and lacto-N-fucopentaose I (LNFP-I, Fuc-a1,2-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc) in whole broth samples when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and LacNAc as acceptors.

Example 29. Production of an Oligosaccharide Mixture Comprising, 2′FL, DiFL, 2′FLacNAc, LN3, LNT, LNFP-I and LNFP-II with a Modified E. coli Host

An E. coli strain adapted for LN3 (GlcNAc-b1,3-Gal-b1,4-Glc) and LNT (Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc) production as described in Example 28, was further transformed with an expression plasmid containing a constitutive transcriptional unit for the mutant a1,3/4 fucosidase from Bifidobacterium longum subsp. infantis ATCC 15697 (SEQ ID NO: 18 in U.S. Pat. No. 8,361,756). The novel strain produces an oligosaccharide mixture comprising 2′FL, DiFL, 2′FLacNAc, LN3, LNT, LNFP-I and lacto-N-fucopentaose II (LNFP-II, Gal-b1,3-(Fuc-a1,4)-GlcNAc-b1,3-Gal-b1,4-Glc) in whole broth samples when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and LacNAc as acceptors.

Example 30. Production of an Oligosaccharide Mixture Comprising 3-FL, 3-FLacNAc, LN3, LNnT, LNFP-III and LNFP-VI with a Modified E. coli Host

An E. coli strain modified for GDP-fucose production as described in Example 1 was further adapted for LN3 and LNnT production by a genomic knock-ins of constitutive transcriptional units for the mutant glmS*54 from E. coli (differing from the wild-type E. coli glmS, having UniProt ID P17169, by an A39T, an R250C and an G472S mutation), LgtA from N. meningitidis (UniProt ID Q9JXQ6) and LgtB from N. meningitidis (UniProt ID Q51116). In a next step, the novel strain was further transformed with an expression plasmid containing constitutive transcriptional units for both the H. pylori a-1,3-fucosyltransferase HpFucT (UniProt ID 030511) and its truncated variant missing 66 amino acid residues at its C-terminus as described by Bai et al. (2019, Carb. Res. 480, 1-6). The novel strain produces an oligosaccharide mixture comprising 3-FL, 3-FLacNAc, LN3 and LNnT, lacto-N-fucopentaose III (LNFP-III, Gal-b1,4-(Fuc-a1,3)-GlcNAc-b1,3-Gal-b1,4-Glc) and lacto-N-fucopentaose VI (LNFP-VI, Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-(Fuc-a1,3-)Glc) in whole broth samples when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and LacNAc as acceptors.

Example 31. Production of an Oligosaccharide Mixture Comprising LN3, Sialylated LN3, LNT, 3′SL, 3′SLacNAc and LSTa with a Modified E. coli Host

An E. coli strain modified to produce sialic acid as described in Example 1 was further modified with a genomic knock-in of constitutive transcriptional units for the galactoside beta-1,3-N-acetylglucosaminyltransferase (LgtA) from N. meningitidis (UniProt ID Q9JXQ6) and for the N-acetylglucosamine beta-1,3-galactosyltransferase (WbgO) from E. coli O55:H7 (UniProt ID D3QY14) to allow production of lacto-N-tetraose (LNT, Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc). In a next step, the novel strain was further modified with a genomic knock-out of the E. coli lacZ gene and transformed with an expression plasmid having constitutive transcriptional units for NeuA from P. multocida (GenBank: AMK07891.1) and a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity. The novel strain produces an oligosaccharide mixture comprising LN3, 3′-sialylated LN3 (Neu5Ac-a2,3-GlcNAc-b1,3-Gal-b1,4-Glc), LNT, 3′SL, 3′SLacNAc and LSTa (Neu5Ac-a2,3-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc) when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose and LacNAc as acceptors.

Example 32. Production of an Oligosaccharide Mixture Comprising LN3, Sialylated LN3, LNnT, 6′SL, 6′SLacNAc and LSTc with a Modified E. coli Host

An E. coli strain modified to produce sialic acid as described in Example 1 was further modified with a genomic knock-in of constitutive transcriptional units for LgtA from N. meningitidis (UniProt ID Q9JXQ6) and for LgtB from N. meningitidis (UniProt ID Q51116) to allow production of lacto-N-neotetraose (LNnT, Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc). In a next step, the novel strain was further modified with a genomic knock-out of the E. coli lacZ gene and transformed with an expression plasmid having constitutive transcriptional units for NeuA from P. multocida (GenBank: AMK07891.1) and a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity. The novel strain produces an oligosaccharide mixture comprising LN3, 6′-sialylated LN3 (Neu5Ac-a2,6-(GlcNAc-b1,3)-Gal-b1,4-Glc), 6′SL, 6′SLacNAc, LNnT and LSTc (Neu5Ac-a2,6-Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc) when evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains glycerol as carbon source and lactose and LacNAc as acceptors.

Example 33. Production of an Oligosaccharide Mixture Comprising 2′FL and DiFL with a Modified S. cerevisiae Host Using Lactose and 3-FL as Acceptors

An S. cerevisiae strain was adapted for GDP-fucose production and fucosyltransferase expression as described in Example 2 with a yeast expression plasmid (a variant of p2a_2μ_Fuc) comprising constitutive transcriptional units for the lactose permease (LAC12) from K. lactis (UniProt ID P07921), the GDP-mannose 4,6-dehydratase (gmd) from E. coli (UniProt ID P0AC88), the GDP-L-fucose synthase (fcl) from E. coli (UniProt ID P32055) and the alpha-1,2-fucosyltransferase from H. pylori HpFutC (GenBank: AAD29863.1). When evaluated on SD CSM-Ura drop-out medium comprising lactose and 3-FL as acceptors, the mutant yeast strain produces an oligosaccharide mixture comprising 2′FL and DiFL.

Example 34. Production of an Oligosaccharide Mixture Comprising 2′FL, 3-FL, DiFL, 2′FLacNAc, 3-FLacNAc and DiFLacNAc with a Modified S. cerevisiae Host Using Lactose and LacNAc as Acceptors

An S. cerevisiae strain was adapted for GDP-fucose production and fucosyltransferase expression as described in Example 2 with a yeast expression plasmid (a variant of p2a_2μ_Fuc) comprising constitutive transcriptional units for the lactose permease (LAC12) from K. lactis (UniProt ID P07921), the GDP-mannose 4,6-dehydratase (gmd) from E. coli (UniProt ID P0AC88), the GDP-L-fucose synthase (fcl) from E. coli (UniProt ID P32055), the alpha-1,2-fucosyltransferase from H. pylori HpFutC (GenBank: AAD29863.1) and the alpha-1,3-fucosyltransferase from H. pylori HpFucT (UniProt ID 030511). When evaluated on SD CSM-Ura drop-out medium comprising lactose and LacNAc as acceptors, the mutant yeast strain produces an oligosaccharide mixture comprising 2′FL, 3-FL, DiFL, 2′FLacNAc, 3-FLacNAc and DiFLacNAc.

Example 35. Production of an Oligosaccharide Mixture Comprising 3′SL, 6′SL, 3′SLacNAc and 6′SLacNAc with a Modified S. cerevisiae Host Using Lactose and LacNAc as Acceptors

An S. cerevisiae strain was adapted for production of CMP-sialic acid and for expression of two sialyltransferases as described in Example 2 with a yeast expression plasmid (a pRS420-plasmid variant) comprising constitutive transcriptional units for the mutant glmS*54 from E. coli (differing from the wild-type E. coli glmS, having UniProt ID P17169, by an A39T, an R250C and an G472S mutation), the phosphatase yqaB from E. coli (GenBank NO. NP_417175.1), AGE from B. ovatus (UniProt ID A7LVG6), neuB from N. meningitidis (UniProt ID E0NCD4), neuA from P. multocida (GenBank: AMK07891.1), a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity and a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity. When evaluated on SD CSM-Trp drop-out medium comprising lactose and LacNAc as acceptors, the mutant yeast strain produces an oligosaccharide mixture comprising 3′SL, 6′SL, 3′SLacNAc and 6′SLacNAc.

Example 36. Evaluation of Mutant E. coli Strains in Fed-Batch Fermentations

The mutant E. coli strains as described in Examples 4 and 5 are evaluated in a fed-batch fermentation process. Fed-batch fermentations at bioreactor scale are performed as described in Example 1. Sucrose was used as a carbon source and lactose and LacNAc are added in the batch medium as acceptors. In contrast to the cultivation experiments that are described herein and wherein only end samples were taken at the end of cultivation (i.e., 72 hours as described herein), regular broth samples are taken at several time points during the fermentation process and the production of an oligosaccharide mixture comprising 2′FL, DiFL and 2′FLacNAc or an oligosaccharide mixture comprising 2′FL, 3-FL, DiFL, 2′FLacNAc, 3-FLacNAc and DiFLacNAc is evaluated for the strain described in Example 4 or 5, respectively.

Example 37. Evaluation of Mutant E. coli Strains in Fed-Batch Fermentations

The mutant E. coli strain as described in Example 27 is evaluated in a fed-batch fermentation process. Fed-batch fermentations at bioreactor scale are performed as described in Example 1. Sucrose was used as a carbon source and lactose, LacNAc and LNB are added in the batch medium as acceptors. In contrast to the cultivation experiments that are described herein and wherein only end samples were taken at the end of cultivation (i.e., 72 hours as described herein), regular broth samples are taken at several time points during the fermentation process and the production of an oligosaccharide mixture comprising 3′SL, 6′SL, 3′SLacNAc, 6′SLacNAc, 3′SLNB and 6′SLNB is evaluated.

Example 38. Material and Methods Bacillus subtilis

Media

Two different media are used, namely a rich Luria Broth (LB) and a minimal medium for shake flask (MMsf). The minimal medium uses a trace element mix.

Trace element mix consisted of 0.735 g/L CaCl₂·2H₂O, 0.1 g/L MnCl₂·2H₂O, 0.033 g/L CuCl₂·2H₂O, 0.06 g/L CoCl₂·6H₂O, 0.17 g/L ZnCl₂, 0.0311 g/L H₃BO₄, 0.4 g/L Na₂EDTA·2H₂O and 0.06 g/L Na₂MoO₄. The Fe-citrate solution contained 0.135 g/L FeCl₃·6H₂O, 1 g/L Na-citrate (Hoch 1973 PMC1212887).

The Luria Broth (LB) medium consisted of 1% tryptone peptone (Difco, Erembodegem, Belgium), 0.5% yeast extract (Difco) and 0.5% sodium chloride (VWR. Leuven, Belgium). Luria Broth agar (LBA) plates consisted of the LB media, with 12 g/L agar (Difco, Erembodegem, Belgium) added.

The minimal medium for the shake flasks (MMsf) experiments contained 2.00 g/L (NH₄)₂SO₄, 7.5 g/L KH₂PO₄, 17.5 g/L K2HPO₄, 1.25 g/L Na-citrate, 0.25 g/L MgSO₄·7H₂O, 0.05 g/L tryptophan, from 10 up to 30 g/L glucose or another carbon source including but not limited to fructose, maltose, sucrose, glycerol and maltotriose when specified in the examples, 10 ml/L trace element mix and 10 ml/L Fe-citrate solution. The medium was set to a pH of 7 with 1M KOH. Depending on the experiment lactose, 2′FL, 3-FL, 3′SL, LNB or LacNAc could be added as an acceptor.

Complex medium, e.g., LB, was sterilized by autoclaving (121° C., 21′) and minimal medium by filtration (0.22 μm Sartorius). When necessary, the medium was made selective by adding an antibiotic (e.g., zeocin (20 mg/L)).

Strains, Plasmids and Mutations

Bacillus subtilis 168, available at Bacillus Genetic Stock Center (Ohio, USA).

Plasmids for gene deletion via Cre/lox are constructed as described by Yan et al. (Appl. & Environm. Microbial., September 2008, p5556-5562). Gene disruption is done via homologous recombination with linear DNA and transformation via electroporation as described by Xue et al. (J. Microb. Meth. 34 (1999) 183-191). The method of gene knockouts is described by Liu et al. (Metab. Engine. 24 (2014) 61-69). This method uses 1000 bp homologies up- and downstream of the target gene.

Integrative vectors as described by Popp et al. (Sci. Rep., 2017, 7, 15158) are used as expression vector and could be further used for genomic integrations if necessary. A suitable promoter for expression can be derived from the part repository (iGem): sequence id: Bba_K143012, Bba_K823000, Bba_K823002 or Bba_K823003. Cloning can be performed using Gibson Assembly, Golden Gate assembly, Cliva assembly, LCR or restriction ligation.

In an example for the production of lactose-based oligosaccharides, Bacillus subtilis mutant strains are created to contain a gene coding for a lactose importer (such as e.g., the E. coli lacY with UniProt ID P02920). For 2′FL, 3FL and diFL production, an alpha-1,2- and/or alpha-1,3-fucosyltransferase expression construct is additionally added to the strains.

In an example for the production of lacto-N-triose (LNT-II, LN3, GlcNAc-b1,3-Gal-b1,4-Glc), the B. subtilis strain is modified with a genomic knock-in of constitutive expression units comprising a lactose importer (such as e.g., the E. coli lacY with UniProt ID P02920) and a galactoside beta-1,3-N-acetylglucosaminyltransferase like e.g., LgtA from N. meningitidis (GenBank: AAM33849.1). For LNT production, the LN3 producing strain is further modified with a constitutive transcriptional unit for an N-acetylglucosamine beta-1,3-galactosyltransferase like e.g., WbgO from E. coli O55:H7 (UniProt ID D3QY14). For the production of lacto-N-neotetraose (LNnT, Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc), the LN3 producing strain is further modified with a constitutive transcriptional unit for an N-acetylglucosamine beta-1,4-galactosyltransferase like e.g., LgtB from Neisseria meningitidis (UniProt ID Q51116). Both the N-acetylglucosamine beta-1,3-galactosyltransferase and the N-acetylglucosamine beta-1,4-galactosyltransferase can be delivered to the strain either via genomic knock-in or from an expression plasmid. For the production of LNFP-I and other fucosylated derivatives of LNT and/or LNnT, the LNT and LNnT producing strains can further be modified with an alpha-1,2-fucosyltransferase and/or an alpha-1,3-fucosyltransferase expression construct.

In an example for sialic acid production, a mutant B. subtilis strain is created by overexpressing the native fructose-6-P-aminotransferase (UniProt ID P0CI73) to enhance the intracellular glucosamine-6-phosphate pool. Further on, the enzymatic activities of the genes nagA, nagB and gamA are disrupted by genetic knockouts and a glucosamine-6-P-aminotransferase from S. cerevisiae (UniProt ID P43577), an N-acetylglucosamine-2-epimerase from B. ovatus (UniProt ID A7LVG6) and an N-acetylneuraminate synthase from C. jejuni (UniProt ID Q93MP9) are overexpressed on the genome. To allow sialylated oligosaccharide production, the sialic acid producing strain is further modified with expression constructs comprising the N-acylneuraminate cytidylyltransferase NeuA from C. jejuni (UniProt ID Q93MP7) and one or more copies of a beta-galactoside alpha-2,3-sialyltransferase like e.g., PmultST3 from P. multocida (UniProt ID Q9CLP3) or a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity, NmeniST3 from N. meningitidis (GenBank No. ARC07984.1) or PmultST2 from P. multocida subsp. multocida str. Pm70 (GenBank No. AAK02592.1), a beta-galactoside alpha-2,6-sialyltransferase like e.g., PdST6 from Photobacterium damselae (UniProt ID 066375) or a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity or P-JT-ISH-224-ST6 from Photobacterium sp. JT-ISH-224 (UniProt ID A8QYL1) or a P-JT-ISH-224-ST6-like polypeptide comprising amino acid residues 18 to 514 of UniProt ID A8QYL1 having beta-galactoside alpha-2,6-sialyltransferase activity, and/or an alpha-2,8-sialyltransferase like e.g., from M. musculus (UniProt ID Q64689).

Heterologous and Homologous Expression

Genes that needed to be expressed, be it from a plasmid or from the genome were synthetically synthetized with one of the following companies: DNA2.0, Gen9, Twist Biosciences or IDT.

Expression could be further facilitated by optimizing the codon usage to the codon usage of the expression host. Genes were optimized using the tools of the supplier.

Cultivation Conditions

A preculture of 96-well microtiter plate experiments was started from a cryovial or a single colony from an LB plate, in 150 μL LB and was incubated overnight at 37° C. on an orbital shaker at 800 rpm. This culture was used as inoculum for a 96-well square microtiter plate, with 400 μL MMsf medium by diluting 400×. Each strain was grown in multiple wells of the 96-well plate as biological replicates. These final 96-well culture plates were then incubated at 37° C. on an orbital shaker at 800 rpm for 72 h, or shorter, or longer. At the end of the cultivation experiment samples were taken from each well to measure the supernatant concentration (extracellular sugar concentrations, after 5 min. spinning down the cells), or by boiling the culture broth for 15 min at 90° C. or for 60 min at 60° C. before spinning down the cells (=whole broth concentration, intra- and extracellular sugar concentrations, as defined herein).

Also, a dilution of the cultures was made to measure the optical density at 600 nm. The cell performance index or CPI was determined by dividing the oligosaccharide concentrations by the biomass, in relative percentages compared to a reference strain. The biomass is empirically determined to be approximately ⅓rd of the optical density measured at 600 nm.

Example 39. Production of an Oligosaccharide Mixture Comprising 2′FL, LN3, LNT, LNFP-I and 2′FLNB with a Modified B. subtilis Host

A B. subtilis strain is first modified for LN3 production and growth on sucrose by genomic knock-out of the nagB, glmS and gamA genes and genomic knock-ins of constitutive transcriptional units comprising genes encoding the lactose permease (LacY) from E. coli (UniProt ID P02920), the native fructose-6-P-aminotransferase (UniProt ID P0CI73), the galactoside beta-1,3-N-acetylglucosaminyltransferase LgtA from N. meningitidis (GenBank: AAM33849.1), the sucrose transporter (CscB) from E. coli W (UniProt ID E0IXR1), the fructose kinase (Frk) from Z. mobilis (UniProt ID Q03417) and the sucrose phosphorylase (BaSP) from B. adolescentis (UniProt ID A0ZZH6). In a next step, the mutant strain is further modified with a genomic knock-in of a constitutive transcriptional unit comprising the N-acetylglucosamine beta-1,3-galactosyltransferase WbgO from E. coli O55:H7 (UniProt ID D3QY14) to produce LNT. In a subsequent step, the LNT producing strain is transformed with an expression plasmid comprising constitutive transcriptional units for the alpha-1,2-fucosyltransferase HpFutC from H. pylori (GenBank: AAD29863.1). The novel strain is evaluated for the production of an oligosaccharide mixture comprising 2′FL, LN3, LNT, LNFP-I (Fuc-a1,2-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc) and 2′FLNB (Fuc-a1,2-Gal-b1,3-GlcNAc) in a growth experiment on MMsf medium comprising lactose and LNB as acceptors according to the culture conditions provided in Example 38. After 72 h of incubation, the culture broth is harvested, and the sugars are analyzed on UPLC.

Example 40. Production of an Oligosaccharide Mixture Comprising 2′FL, LN3, LNT, Sialylated LN3, LSTa, LNFP-I, 2′FLNB, 3′-SL and Sialylated LNB with a Modified B. subtilis Host

The mutant B. subtilis strain capable of producing 2′FL, LN3, LNT, LNFP-I (Fuc-a1,2-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc) and 2′FLNB (Fuc-a1,2-Gal-b1,3-GlcNAc) as described in Example 39 is further modified with a genomic knock-out of the nagA gene and a second compatible expression plasmid comprising the TRP1 selection marker and constitutive transcriptional units for two copies of the mutant L-glutamine-D-fructose-6-phosphate aminotransferase (glmS*54) from E. coli (differing from the wild-type E. coli glmS, having UniProt ID P17169, by an A39T, an R250C and an G472S mutation), a phosphatase chosen from the E. coli genes comprising aphA, Cof, HisB, OtsB, SurE, Yaed, YcjU, YedP, YfbT, YidA, YigB, YihX, YniC, YqaB, YrbL, AppA, Gph, SerB, YbhA, YbiV, YbjL, Yfb, YieH, YjgL, YjjG, YrfG and YbiU or PsMupP from P. putida, ScDOG1 from S. cerevisiae or BsAraL from B. subtilis as described in WO 2018122225, the N-acetylglucosamine 2-epimerase (AGE) from B. ovatus (UniProt ID A7LVG6), the N-acetylneuraminate synthase (NeuB) from N. meningitidis (UniProt ID E0NCD4), the N-acylneuraminate cytidylyltransferase NeuA from Haemophilus influenzae (GenBank No. AGV11798.1) and three copies of the PmultST3 polypeptide from P. multocida (UniProt ID Q9CLP3).

The novel strain is evaluated for the production of a mixture comprising 2′FL, LN3, LNT, LNFP-I (Fuc-a1,2-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc), 2′FLNB (Fuc-a1,2-Gal-b1,3-GlcNAc), 3′-SL, sialylated LN3, sialylated LNB and LSTa (Neu5Ac-a2,3-Gal-b1,3-GlcNAc-b1,3-Gal-b1,4-Glc) in a growth experiment on MMsf medium comprising lactose and LNB as acceptors according to the culture conditions provided in Example 38. After 72 h of incubation, the culture broth is harvested, and the sugars are analyzed on UPLC.

Example 41. Material and Methods Corynebacterium glutamicum

Media

Two different media are used, namely a rich tryptone-yeast extract (TY) medium and a minimal medium for shake flask (MMsf). The minimal medium uses a 1000×stock trace element mix.

Trace element mix consisted of 10 g/L CaCl₂), 10 g/L FeSO₄·7H₂O, 10 g/L MnSO₄·H₂O, 1 g/L ZnSO₄·7H₂O, 0.2 g/L CuSO₄, 0.02 g/L NiCl₂·6H₂O, 0.2 g/L biotin (pH 7.0) and 0.03 g/L protocatechuic acid.

The minimal medium for the shake flasks (MMsf) experiments contained 20 g/L (NH₄)₂SO₄, 5 g/L urea, 1 g/L KH₂PO₄, 1 g/L K2HPO₄, 0.25 g/L MgSO₄·7H₂O, 42 g/L MOPS, from 10 up to 30 g/L glucose or another carbon source including but not limited to fructose, maltose, sucrose, glycerol and maltotriose when specified in the examples and 1 ml/L trace element mix. Depending on the experiment lactose, LNB and/or LacNAc could be added as an acceptor.

The TY medium consisted of 1.6% tryptone (Difco, Erembodegem, Belgium), 1% yeast extract (Difco) and 0.5% sodium chloride (VWR. Leuven, Belgium). TY agar (TYA) plates consisted of the TY media, with 12 g/L agar (Difco, Erembodegem, Belgium) added.

Complex medium, e.g., TY, was sterilized by autoclaving (121° C., 21′) and minimal medium by filtration (0.22 μm Sartorius). When necessary, the medium was made selective by adding an antibiotic (e.g., kanamycin, ampicillin).

Strains and Mutations

Corynebacterium glutamicum ATCC 13032, available at the American Type Culture Collection.

Integrative plasmid vectors based on the Cre/loxP technique as described by Suzuki et al. (Appl. Microbiol. Biotechnol., 2005 April, 67(2):225-33) and temperature-sensitive shuttle vectors as described by Okibe et al. (Journal of Microbiological Methods 85, 2011, 155-163) are constructed for gene deletions, mutations and insertions. Suitable promoters for (heterologous) gene expression can be derived from Yim et al. (Biotechnol. Bioeng., 2013 November, 110(11):2959-69). Cloning can be performed using Gibson Assembly, Golden Gate assembly, Cliva assembly, LCR or restriction ligation.

In an example for the production of lactose-based oligosaccharides, C. glutamicum mutant strains are created to contain a gene coding for a lactose importer (such as e.g., the E. coli lacY with UniProt ID P02920). For 2′FL, 3FL and diFL production, an alpha-1,2- and/or alpha-1,3-fucosyltransferase expression construct is additionally added to the strains.

In an example for the production of lacto-N-triose (LNT-II, LN3, GlcNAc-b1,3-Gal-b1,4-Glc), the C. glutamicum strain is modified with a genomic knock-in of constitutive expression units comprising a lactose importer (such as e.g., the E. coli lacY with UniProt ID P02920) and a galactoside beta-1,3-N-acetylglucosaminyltransferase like e.g., LgtA from N. meningitidis (GenBank: AAM33849.1). For LNT production, the LN3 producing strain is further modified with a constitutive transcriptional unit for an N-acetylglucosamine beta-1,3-galactosyltransferase like e.g., WbgO from E. coli O55:H7 (UniProt ID D3QY14). For the production of lacto-N-neotetraose (LNnT, Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc), the LN3 producing strain is further modified with a constitutive transcriptional unit for an N-acetylglucosamine beta-1,4-galactosyltransferase like e.g., LgtB from Neisseria meningitidis (UniProt ID Q51116). Both the N-acetylglucosamine beta-1,3-galactosyltransferase and the N-acetylglucosamine beta-1,4-galactosyltransferase can be delivered to the strain either via genomic knock-in or from an expression plasmid. For the production of LNFP-I, the LNT producing strain can further be modified with an alpha-1,2-fucosyltransferase expression construct.

In an example for sialic acid production, a mutant C. glutamicum strain is created by overexpressing the native fructose-6-P-aminotransferase (UniProt ID Q8NND3) to enhance the intracellular glucosamine-6-phosphate pool. Further on, the enzymatic activities of the genes nagA, nagB and gamA are disrupted by genetic knockouts and a glucosamine-6-P-aminotransferase from S. cerevisiae (UniProt ID P43577), an N-acetylglucosamine-2-epimerase from B. ovatus (UniProt ID A7LVG6) and an N-acetylneuraminate synthase from C. jejuni (UniProt ID Q93MP9) are overexpressed on the genome. To allow sialylated oligosaccharide production, the sialic acid producing strain is further modified with expression constructs comprising an N-acylneuraminate cytidylyltransferase like e.g., the NeuA enzyme from C. jejuni (UniProt ID Q93MP7), the NeuA enzyme from H. influenzae (GenBank No. AGV11798.1) or the NeuA enzyme from P. multocida (GenBank No. AMK07891.1), and one or more copies of a beta-galactoside alpha-2,3-sialyltransferase like e.g., PmultST3 from P. multocida (UniProt ID Q9CLP3) or a PmultST3-like polypeptide comprising amino acid residues 1 to 268 of UniProt ID Q9CLP3 having beta-galactoside alpha-2,3-sialyltransferase activity, NmeniST3 from N. meningitidis (GenBank No. ARC07984.1) or PmultST2 from P. multocida subsp. multocida str. Pm70 (GenBank No. AAK02592.1), a beta-galactoside alpha-2,6-sialyltransferase like e.g., PdST6 from Photobacterium damselae (UniProt ID 066375) or a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity or P-JT-ISH-224-ST6 from Photobacterium sp. JT-ISH-224 (UniProt ID A8QYL1) or a P-JT-ISH-224-ST6-like polypeptide comprising amino acid residues 18 to 514 of UniProt ID A8QYL1 having beta-galactoside alpha-2,6-sialyltransferase activity, and/or an alpha-2,8-sialyltransferase like e.g., from M. musculus (UniProt ID Q64689).

Heterologous and Homologous Expression

Genes that needed to be expressed, be it from a plasmid or from the genome were synthetically synthetized with one of the following companies: DNA2.0, Gen9, Twist Biosciences or IDT.

Expression could be further facilitated by optimizing the codon usage to the codon usage of the expression host. Genes were optimized using the tools of the supplier.

Cultivation Conditions

A preculture of 96-well microtiter plate experiments was started from a cryovial or a single colony from a TY plate, in 150 μL TY and was incubated overnight at 37° C. on an orbital shaker at 800 rpm. This culture was used as inoculum for a 96-well square microtiter plate, with 400 μL MMsf medium by diluting 400×. Each strain was grown in multiple wells of the 96-well plate as biological replicates. These final 96-well culture plates were then incubated at 37° C. on an orbital shaker at 800 rpm for 72 h, or shorter, or longer. At the end of the cultivation experiment samples were taken from each well to measure the supernatant concentration (extracellular sugar concentrations, after 5 min. spinning down the cells), or by boiling the culture broth for 15 min at 60° C. before spinning down the cells (=whole broth concentration, intra- and extracellular sugar concentrations, as defined herein).

Also, a dilution of the cultures was made to measure the optical density at 600 nm. The cell performance index or CPI was determined by dividing the oligosaccharide concentrations, e.g., sialyllactose concentrations, measured in the whole broth by the biomass, in relative percentages compared to the reference strain. The biomass is empirically determined to be approximately ⅓rd of the optical density measured at 600 nm.

Example 42. Production of an Oligosaccharide Mixture Comprising LN3, LNT, LNFP-I, 2′-FL and 2′FLNB with a Modified C. glutamicum Host

A C. glutamicum strain is first modified for LN3 production and growth on sucrose by genomic knock-out of the ldh, cgl2645 and nagB genes and genomic knock-ins of constitutive transcriptional units comprising genes encoding the lactose permease (LacY) from E. coli (UniProt ID P02920), native fructose-6-P-aminotransferase (UniProt ID Q8NND3), the galactoside beta-1,3-N-acetylglucosaminyltransferase LgtA from N. meningitidis (GenBank: AAM33849.1), the sucrose transporter (CscB) from E. coli W (UniProt ID E0IXR1), the fructose kinase (Frk) from Z. mobilis (UniProt ID Q03417) and the sucrose phosphorylase (BaSP) from B. adolescentis (UniProt ID A0ZZH6). In a next step, the mutant strain is further modified with a genomic knock-in of a constitutive transcriptional unit comprising the N-acetylglucosamine beta-1,3-galactosyltransferase WbgO from E. coli O55:H7 (UniProt ID D3QY14) to produce LNT. In a subsequent step, the LNT producing strain is transformed with an expression plasmid comprising constitutive transcriptional units for the alpha-1,2-fucosyltransferase HpFutC from H. pylori (GenBank: AAD29863.1). The novel strain is evaluated for the production of an oligosaccharide mixture comprising LN3, LNT, LNFP-I, 2′-FL and 2′FLNB in a growth experiment on MMsf medium comprising lactose and LNB as acceptors according to the culture conditions provided in Example 41. After 72 h of incubation, the culture broth is harvested, and the sugars are analyzed on UPLC.

Example 43. Production of an Oligosaccharide Mixture Comprising LN3, Sialylated LN3, LNnT, 6′SL, 6′SLacNAc and LSTc with a Modified C. glutamicum Host

A C. glutamicum strain is first modified to produce sialic acid by a genomic knock-out of the ldh, cgl2645, nagA and nagB genes together with genomic knock-ins of constitutive transcriptional units comprising native fructose-6-P-aminotransferase (UniProt ID Q8NND3), a glucosamine-6-P-aminotransferase from S. cerevisiae (UniProt ID P43577), an N-acetylglucosamine-2-epimerase from B. ovatus (UniProt ID A7LVG6) and an N-acetylneuraminate synthase from C. jejuni (UniProt ID Q93MP9). The C. glutamicum strain is further modified with a genomic knock-in of constitutive transcriptional units for the lactose permease LacY from E. coli (UniProt ID P02920), LgtA from N. meningitidis (UniProt ID Q9JXQ6) and for LgtB from N. meningitidis (UniProt ID Q51116) to allow production of LN3 and lacto-N-neotetraose (LNnT, Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc). In a next step, the mutant strain is transformed with an expression plasmid having constitutive transcriptional units for NeuA from P. multocida (GenBank: AMK07891.1) and a PdST6-like polypeptide comprising amino acid residues 108 to 497 of UniProt ID 066375 having beta-galactoside alpha-2,6-sialyltransferase activity. The novel strain is evaluated for the production of an oligosaccharide mixture comprising LN3, 6′-sialylated LN3 (Neu5Ac-a2,6-(GlcNAc-b1,3)-Gal-b1,4-Glc), 6′SL, 6′SLacNAc, LNnT and LSTc (Neu5Ac-a2,6-Gal-b1,4-GlcNAc-b1,3-Gal-b1,4-Glc) in a growth experiment on MMsf medium comprising lactose and LacNAc as acceptors according to the culture conditions provided in Example 41. After 72 h of incubation, the culture broth is harvested, and the sugars are analyzed on UPLC.

Example 44. Materials and Methods Chlamydomonas reinhardtii

Media

C. reinhardtii cells were cultured in Tris-acetate-phosphate (TAP) medium (pH 7.0). The TAP medium uses a 1000×stock Hutner's trace element mix. Hutner's trace element mix consisted of 50 g/L Na₂EDTA·H₂O (Titriplex III), 22 g/L ZnSO₄·7H₂O, 11.4 g/L H₃BO₃, 5 g/L MnCl₂·4H₂O, 5 g/L FeSO₄·7H₂O, 1.6 g/L CoCl₂·6H₂O, 1.6 g/L CuSO₄·5H₂O and 1.1 g/L (NH₄)₆MoO₃.

The TAP medium contained 2.42 g/L Tris (tris(hydroxymethyl)aminomethane), 25 mg/L salt stock solution, 0.108 g/L K2HPO₄, 0.054 g/L KH₂PO₄ and 1.0 mL/L glacial acetic acid. The salt stock solution consisted of 15 g/L NH₄Cl, 4 g/L MgSO₄·7H₂O and 2 g/L CaCl₂·2H₂O. As precursor and/or acceptor for saccharide synthesis, precursors and/or acceptors like e.g., galactose, glucose, fructose, fucose, GlcNAc, LNB and/or LacNAc could be added. Medium was sterilized by autoclaving (121° C., 21′). For stock cultures on agar slants TAP medium was used containing 1% agar (of purified high strength, 1000 g/cm²).

Strains, Plasmids and Mutations

C. reinhardtii wild-type strains 21 gr (CC-1690, wild-type, mt+), 6145C (CC-1691, wild-type, mt−), CC-125 (137c, wild-type, mt+), CC-124 (137c, wild-type, mt−) as available from Chlamydomonas Resource Center (www.chlamycollection.org), University of Minnesota, U.S.A.

Expression plasmids originated from pSI103, as available from Chlamydomonas Resource Center. Cloning can be performed using Gibson Assembly, Golden Gate assembly, Cliva assembly, LCR or restriction ligation. Suitable promoters for (heterologous) gene expression can be derived from e.g., Scranton et al. (Algal Res. 2016, 15: 135-142). Targeted gene modification (like gene knock-out or gene replacement) can be carried using the CRISPR-Cas technology as described e.g., by Jiang et al. (Eukaryotic Cell 2014, 13(11): 1465-1469).

Transformation via electroporation was performed as described by Wang et al. (Biosci. Rep. 2019, 39: BSR2018210). Cells were grown in liquid TAP medium under constant aeration and continuous light with a light intensity of 8000 Lx until the cell density reached 1.0-2.0×10⁷ cells/mL. Then, the cells were inoculated into fresh liquid TAP medium in a concentration of 1.0×10⁶ cells/mL and grown under continuous light for 18-20 h until the cell density reached 4.0×10⁶ cells/mL. Next, cells were collected by centrifugation at 1250 g for 5 min at room temperature, washed and resuspended with pre-chilled liquid TAP medium containing 60 mM sorbitol (Sigma, U.S.A.), and iced for 10 min. Then, 250 μL of cell suspension (corresponding to 5.0×10⁷ cells) were placed into a pre-chilled 0.4 cm electroporation cuvette with 100 ng plasmid DNA (400 ng/mL). Electroporation was performed with 6 pulses of 500 V each having a pulse length of 4 ms and pulse interval time of 100 ms using a BTX ECM830 electroporation apparatus (1575Ω, 50 μFD). After electroporation, the cuvette was immediately placed on ice for 10 min. Finally, the cell suspension was transferred into a 50 ml conical centrifuge tube containing 10 mL of fresh liquid TAP medium with 60 mM sorbitol for overnight recovery at dim light by slowly shaking. After overnight recovery, cells were recollected and plated with starch embedding method onto selective 1.5% (w/v) agar-TAP plates containing ampicillin (100 mg/L) or chloramphenicol (100 mg/L). Plates were then incubated at 23+/−0.5° C. under continuous illumination with a light intensity of 8000 Lx. Cells were analyzed 5-7 days later.

In an example for production of GDP-fucose, C. reinhardtii cells are modified with a transcriptional unit for the GDP-fucose synthase from Arabidopsis thaliana (GER1, UniProt ID O49213).

In an example for production of UDP-galactose, C. reinhardtii cells are modified with transcriptional units comprising the genes encoding the galactokinase from Arabidopsis thaliana (KIN, UniProt ID Q9SEE5) and the UDP-sugar pyrophosphorylase (USP) from A. thaliana (UniProt ID Q9C5I1).

In an example for production of UDP-N-acetylgalactosamine, C. reinhardtii cells are modified with a transcriptional unit comprising the UDP-N-acetylglucosamine 4-epimerase wbpP from Pseudomonas aeruginosa serotype O6 (UniProt ID Q8KN66).

In an example for production of LNB, C. reinhardtii cells modified for UDP-galactose production are further modified with an expression plasmid comprising a transcriptional unit for the N-acetylglucosamine beta-1,3-galactosyltransferase WbgO from E. coli O55:H7 (UniProt ID D3QY14). In an example for production of LacNAc, C. reinhardtii cells modified for UDP-galactose production are further modified with an expression plasmid comprising a transcriptional unit for the N-acetylglucosamine beta-1,4-galactosyltransferase LgtB from Neisseria meningitidis (UniProt ID Q51116).

In an example for CMP-sialic acid synthesis, C. reinhardtii cells are modified with constitutive transcriptional units for an UDP-N-acetylglucosamine-2-epimerase/N-acetylmannosamine kinase like e.g., GNE from Homo sapiens (UniProt ID Q9Y223) or a mutant form of the human GNE polypeptide comprising the R263L mutation, an N-acylneuraminate-9-phosphate synthetase like e.g., NANS from Homo sapiens (UniProt ID Q9NR45) and an N-acylneuraminate cytidylyltransferase like e.g., CMAS from Homo sapiens (UniProt ID Q8NFW8). In an example for production of sialylated oligosaccharides, C. reinhardtii cells are modified with a CMP-sialic acid transporter like e.g., CST from Mus musculus (UniProt ID Q61420), and a Golgi-localized sialyltransferase chosen from species like e.g., Homo sapiens, Mus musculus, Rattus norvegicus.

Heterologous and Homologous Expression

Genes that needed to be expressed, be it from a plasmid or from the genome were synthetically synthetized with one of the following companies: DNA2.0, Gen9, Twist Biosciences or IDT.

Expression could be further facilitated by optimizing the codon usage to the codon usage of the expression host. Genes were optimized using the tools of the supplier.

Cultivation Conditions

Cells of C. reinhardtii were cultured in selective TAP-agar plates at 23+/−0.5° C. under 14/10 h light/dark cycles with a light intensity of 8000 Lx. Cells were analyzed after 5 to 7 days of cultivation.

For high-density cultures, cells could be cultivated in closed systems like e.g., vertical or horizontal tube photobioreactors, stirred tank photobioreactors or flat panel photobioreactors as described by Chen et al. (Bioresour. Technol. 2011, 102: 71-81) and Johnson et al. (Biotechnol. Prog. 2018, 34: 811-827).

Example 45. Production of an Oligosaccharide Mixture Comprising 2′FLNB and 2′FLacNAc in Mutant C. reinhardtii Cells

C. reinhardtii cells are engineered as described in Example 44 for production of GDP-fucose with a genomic knock-in of a constitutive transcriptional unit comprising the GDP-fucose synthase gene from Arabidopsis thaliana (GER1, UniProt ID O49213). In a next step, the mutant cells are transformed with an expression plasmid comprising a constitutive transcriptional unit the alpha-1,2-fucosyltransferase HpFutC from H. pylori (GenBank: AAD29863.1). The novel strains are evaluated in a cultivation experiment on TAP-agar plates comprising LNB and LacNAc as acceptors according to the culture conditions provided in Example 44. After 5 days of incubation, the cells are harvested, and the production of 2′FLNB and 2′FLacNAc is analyzed on UPLC.

Example 46. Materials and Methods Animal Cells

Isolation of Mesenchymal Stem Cells from Adipose Tissue of Different Mammals

Fresh adipose tissue is obtained from slaughterhouses (e.g., cattle, pigs, sheep, chicken, ducks, catfish, snake, frogs) or liposuction (e.g., in case of humans, after informed consent) and kept in phosphate buffer saline supplemented with antibiotics. Enzymatic digestion of the adipose tissue is performed followed by centrifugation to isolate mesenchymal stem cells. The isolated mesenchymal stem cells are transferred to cell culture flasks and grown under standard growth conditions, e.g., 37° C., 5% CO₂. The initial culture medium includes DMEM-F12, RPMI, and Alpha-MEM medium (supplemented with 15% fetal bovine serum), and 1% antibiotics. The culture medium is subsequently replaced with 10% FBS (fetal bovine serum)-supplemented media after the first passage. For example, Ahmad and Shakoori (2013, Stem Cell Regen Med. 9(2): 29-36), which is incorporated herein by reference in its entirety for all purposes, describes certain variation(s) of the method(s) described herein in this example.

Isolation of Mesenchymal Stem Cells from Milk

This example illustrates isolation of mesenchymal stem cells from milk collected under aseptic conditions from human or any other mammal(s) such as described herein. An equal volume of phosphate buffer saline is added to diluted milk, followed by centrifugation for 20 min. The cell pellet is washed thrice with phosphate buffer saline and cells are seeded in cell culture flasks in DMEM-F12, RPMI, and Alpha-MEM medium supplemented with 10% fetal bovine serum and 1% antibiotics under standard culture conditions. For example, Hassiotou et al. (2012, Stem Cells. 30(10): 2164-2174), which is incorporated herein by reference in its entirety for all purposes, describes certain variation(s) of the method(s) described herein in this example.

Differentiation of Stem Cells Using 2D and 3D Culture Systems

The isolated mesenchymal cells can be differentiated into mammary-like epithelial and luminal cells in 2D and 3D culture systems. See, for example, Huynh et al. 1991. Exp Cell Res. 197(2): 191-199; Gibson et al. 1991, In Vitro Cell Dev Biol Anim. 27(7): 585-594; Blatchford et al. 1999; Animal Cell Technology’: Basic & Applied Aspects, Springer, Dordrecht. 141-145; Williams et al. 2009, Breast Cancer Res 11(3): 26-43; and Arevalo et al. 2015, Am J Physiol Cell Physiol. 310(5): C348-C356; each of which is incorporated herein by reference in their entireties for all purposes.

For 2D culture, the isolated cells were initially seeded in culture plates in growth media supplemented with 10 ng/ml epithelial growth factor and 5 pg/ml insulin. At confluence, cells were fed with growth medium supplemented with 2% fetal bovine serum, 1% penicillin-streptomycin (100 U/ml penicillin, 100 ug/ml streptomycin), and 5 pg/ml insulin for 48 h. To induce differentiation, the cells were fed with complete growth medium containing 5 pg/ml insulin, 1 pg/ml hydrocortisone, 0.65 ng/ml triiodothyronine, 100 nM dexamethasone, and 1 pg/ml prolactin. After 24 h, serum is removed from the complete induction medium.

For 3D culture, the isolated cells were trypsinized and cultured in Matrigel, hyaluronic acid, or ultra-low attachment surface culture plates for six days and induced to differentiate and lactate by adding growth media supplemented with 10 ng/ml epithelial growth factor and 5 pg/ml insulin. At confluence, cells were fed with growth medium supplemented with 2% fetal bovine serum, 1% penicillin-streptomycin (100 U/ml penicillin, 100 ug/ml streptomycin), and 5 pg/ml insulin for 48 h. To induce differentiation, the cells were fed with complete growth medium containing 5 pg/ml insulin, 1 pg/ml hydrocortisone, 0.65 ng/ml triiodothyronine, 100 nM dexamethasone, and 1 pg/ml prolactin. After 24 h, serum is removed from the complete induction medium.

Method of Making Mammary-Like Cells

Mammalian cells are brought to induced pluripotency by reprogramming with viral vectors encoding for Oct4, Sox2, Klf4, and c-Myc. The resultant reprogrammed cells are then cultured in Mammocult media (available from Stem Cell Technologies), or mammary cell enrichment media (DMEM, 3% FBS, estrogen, progesterone, heparin, hydrocortisone, insulin, EGF) to make them mammary-like, from which expression of select milk components can be induced. Alternatively, epigenetic remodeling are performed using remodeling systems such as CRISPR/Cas9, to activate select genes of interest, such as casein, a-lactalbumin to be constitutively on, to allow for the expression of their respective proteins, and/or to down-regulate and/or knock-out select endogenous genes as described e.g., in WO 2021067641, which is incorporated herein by reference in its entirety for all purposes.

Cultivation

Completed growth media includes high glucose DMEM/F12, 10% FBS, 1% NEAA, 1% pen/strep, 1% ITS-X, 1% F-Glu, 10 ng/ml EGF, and 5 pg/ml hydrocortisone. Completed lactation media includes high glucose DMEM/F12, 1% NEAA, 1% pen/strep, 1% ITS-X, 1% F-Glu, 10 ng/ml EGF, 5 pg/ml hydrocortisone, and 1 pg/ml prolactin (5 ug/ml in Hyunh 1991). Cells are seeded at a density of 20,000 cells/cm² onto collagen coated flasks in completed growth media and left to adhere and expand for 48 hours in completed growth media, after which the media is switched out for completed lactation media. Upon exposure to the lactation media, the cells start to differentiate and stop growing. Within about a week, the cells start secreting lactation product(s) such as milk lipids, lactose, casein and whey into the media. A desired concentration of the lactation media can be achieved by concentration or dilution by ultrafiltration. A desired salt balance of the lactation media can be achieved by dialysis, for example, to remove unwanted metabolic products from the media. Hormones and other growth factors used can be selectively extracted by resin purification, for example, the use of nickel resins to remove His-tagged growth factors, to further reduce the levels of contaminants in the lactated product.

Example 47. Making of an Oligosaccharide Mixture Comprising 2′FLNB, 2′FLacNAc, 2′-FL, Sialylated LNB, Sialylated LacNAc and 3′-SL in a Non-Mammary Adult Stem Cell

Isolated mesenchymal cells and re-programmed into mammary-like cells as described in Example 46 are modified via CRISPR-CAS to over-express the GDP-fucose synthase GFUS from Homo sapiens (UniProt ID Q13630), the human galactoside alpha-1,2-fucosyltransferase FUT1 (UniProt ID P19526), the N-acylneuraminate cytidylyltransferase from Mus musculus (UniProt ID Q99KK2) and the CMP-N-acetylneuraminate-beta-1,4-galactoside alpha-2,3-sialyltransferase ST3GAL3 from Homo sapiens (UniProt ID Q11203). Cells are seeded at a density of 20,000 cells/cm² onto collagen coated flasks in completed growth media and left to adhere and expand for 48 hours in completed growth media, after which the media is switched out for completed lactation media comprising lactose, LacNAc and LNB as precursors for about 7 days. After cultivation as described in Example 46, cells are subjected to UPLC to analyze for production of 2′-FL, 3′-SL, 2′FLNB, 2′FLacNAc, sialylated LNB and sialylated LacNAc.

Example 48. Evaluation of LacNAc, Sialylated LacNAc, Sialyl-Lewis x, Fucosylated LacNAc, 3-FL and 3′-SL Production in a Non-Mammary Adult Stem Cell

Isolated mesenchymal cells and re-programmed into mammary-like cells as described in Example 46 are modified via CRISPR-CAS to over-express the beta-1,4-galactosyltransferase 4 B4GalT4 from Homo sapiens (UniProt ID 060513), the GDP-fucose synthase GFUS from Homo sapiens (UniProt ID Q13630), the galactoside alpha-1,3-fucosyltransferase FUT3 from Homo sapiens (UniProt ID P21217), the N-acylneuraminate cytidylyltransferases from Mus musculus (UniProt ID Q99KK2) and the CMP-N-acetylneuraminate-beta-1,4-galactoside alpha-2,3-sialyltransferase ST3GAL3 from Homo sapiens (UniProt ID Q11203). All genes introduced in the cells are codon-optimized to the host. Cells are seeded at a density of 20,000 cells/cm² onto collagen coated flasks in completed growth media and left to adhere and expand for 48 hours in completed growth media, after which the media is switched out for completed lactation media comprising LacNAc and lactose as acceptors for about 7 days. After cultivation as described in Example 46, cells are subjected to UPLC to analyze for production of LacNAc, sialylated LacNAc, sialyl-Lewis x, fucosylated LacNAc, 3-FL and 3′-SL.

Example 49. Evaluation of the Expression of a Membrane Transporter in a Modified E. coli Host

The modified E. coli hosts described in Examples 29, 30, 31 and 32 are further modified with by a genomic knock-ins of a constitutive transcriptional unit for one membrane transporter protein chosen from the list comprising MdfA from Cronobacter muytjensii (UniProt ID AOA2T7ANQ9), MdfA from Citrobacter youngae (UniProt ID D4BC23), MdfA from E. coli (UniProt ID POAEY8), MdfA from Yokenella regensburgei (UniProt ID G9Z5F4), iceT from E. coli (UniProt ID A0A024L207), iceT from Citrobacter youngae (UniProt ID D4B8A6), nanT from E. coli O6:H1 (UniProt ID Q8FD59), nanT from E. coli O157:H7 (UniProt ID Q8X9G8), nanT from E. albertii (UniProt ID B1EFH1), EntS from E. coli (UniProt ID P24077), EntS from Kluyvera ascorbata (UniProt ID A0A378GQ13) EntS from Salmonella enterica subsp. arizonae (UniProt ID AOA6Y2K4E8), SetA from E. coli (UniProt ID P31675), SetB from E. coli (UniProt ID P33026), SetC from E. coli (UniProt ID P31436), oppF from E. coli (UniProt ID P77737), lmrA from Lactococcus lactis subsp. lactis bv. diacetylactis (UniProt ID A0A1VONEL4) and Blon 2475 from Bifidobacterium longum subsp. infantis (UniProt ID B7GPD4). The novel strains, each expressing one of the membrane transporter proteins, are evaluated in a growth experiment according to the culture conditions provided in Example 1, in which the culture medium contains sucrose as carbon source and lactose and LacNAc as acceptors. Each strain is grown in four biological replicates in a 96-well plate. After 72 h of incubation, the culture broth (i.e., extracellular and intracellular fractions) together with the extracellular and intracellular fractions separately, is harvested and the sugars are analyzed on UPLC.

Claims

1. A method for producing a mixture of at least two different oligosaccharides by a cell, the method comprising the steps of:

i. providing a cell that is capable of expressing a glycosyltransferase and is capable of synthesizing a nucleotide-sugar, wherein the nucleotide-sugar is donor for the glycosyltransferase,

ii. cultivating the cell under conditions permissive to express the glycosyltransferase and to synthesize the nucleotide-sugar,

iii. adding at least two acceptors to the cultivation to enable the cell to produce at least two oligosaccharides, and

iv. optionally separating at least one of the oligosaccharides from the cultivation.

2. The method of claim 1, wherein any one of the acceptors is a disaccharide or a mammalian milk oligosaccharide (MMO).

3. The method of claim 1, wherein the cell is a cell metabolically engineered for the production of the mixture or is modified with at least one gene expression module, wherein the expression from any one of the at least one expression modules is either constitutive or is created by a natural inducer.

4. The method of claim 1, wherein the cell comprises multiple copies of a coding DNA sequence encoding for one protein.

5. The method of claim 1, wherein the cell produces a mixture of three or more different oligosaccharides.

6. The method of claim 1, wherein the cell produces a mixture of different oligosaccharides with at least two oligosaccharides differing in degree of polymerization.

7. The method of claim 1, wherein the glycosyltransferase is selected from the group consisting of a fucosyltransferases, sialyltransferases, galactosyltransferases, glucosyltransferases, mannosyltransferases, N-acetylglucosaminyltransferases, N-acetylgalactosaminyltransferases, N-acetylmannosaminyltransferases, xylosyltransferases, glucuronyltransferases, galacturonyltransferases, glucosaminyltransferases, N-glycolylneuraminyltransferases, rhamnosyltransferases, N-acetylrhamnosyltransferases, UDP-4-amino-4,6-dideoxy-N-acetyl-beta-L-altrosamine transaminases, UDP-N-acetylglucosamine enolpyruvyl transferases and or fucosaminyltransferase.

8. The method of claim 1, wherein the cell is modified in the expression or activity of the glycosyltransferase.

9. The method of claim 1, wherein the glycosyltransferase is:

a fucosyltransferase and the donor nucleotide-sugar is GDP-Fucose (GDP-Fuc), or

a sialyltransferase and the donor nucleotide-sugar is CMP-N-acetylneuraminic acid (CMP-Neu5Ac), or

an N-acetylglucosaminyltransferase and the donor nucleotide-sugar is UDP-N-acetylglucosamine (UDP-GlcNAc), or

a galactosyltransferase and the donor nucleotide-sugar is UDP-galactose (UDP-Gal), or

an N-acetylgalactosaminyltransferase and the donor nucleotide-sugar is UDP-N-acetylgalactosamine (UDP-GalNAc), or

an N-acetylmannosaminyltransferase and the donor nucleotide-sugar is UDP-N-acetylmannosamine (UDP-ManNAc).

10.-14. (canceled)

15. The method of claim 1, wherein the nucleotide-sugar comprises GDP-Fuc, CMP-Neu5Ac, UDP-GlcNAc, UDP-Gal, UDP-N-acetylgalactosamine (UDP-GalNAc), UDP-N-acetylmannosamine (UDP-ManNAc), GDP-mannose (GDP-Man), UDP-glucose (UDP-Glc), UDP-2-acetamido-2,6-dideoxy-L-arabino-4-hexulose, UDP-2-acetamido-2,6-dideoxy-L-lyxo-4-hexulose, UDP-N-acetyl-L-rhamnosamine (UDP-L-RhaNAc or UDP-2-acetamido-2,6-dideoxy-L-mannose), dTDP-N-acetylfucosamine, UDP-N-acetylfucosamine (UDP-L-FucNAc or UDP-2-acetamido-2,6-dideoxy-L-galactose), UDP-N-acetyl-L-pneumosamine (UDP-L-PneNAC or UDP-2-acetamido-2,6-dideoxy-L-talose), UDP-N-acetylmuramic acid, UDP-N-acetyl-L-quinovosamine (UDP-L-QuiNAc or UDP-2-acetamido-2,6-dideoxy-L-glucose), GDP-L-quinovose, CMP-N-glycolylneuraminic acid (CMP-Neu5Gc), CMP-Neu4Ac, CMP-Neu5Ac9N3, CMP-Neu4,5Ac2, CMP-Neu5,7Ac2, CMP-Neu5,9Ac2, CMP-Neu5,7(8,9)Ac2, UDP-glucuronate, UDP-galacturonate, GDP-rhamnose, or UDP-xylose.

16. The method of claim 1, wherein any one of the acceptors has a degree of polymerization of 3 or more.

17. The method of claim 1, wherein all of the acceptors have a different degree of polymerization.

18. The method of claim 1, wherein the cultivation is supplemented with at least 3 acceptors for the production of the oligosaccharide mixture.

19. The method of claim 1, wherein the oligosaccharide mixture comprises at least one oligosaccharide that is fucosylated, sialylated, is galactosylated, is glucosylated, is xylosylated, is mannosylated, contains an N-acetylglucosamine, contains an N-acetylneuraminate, contains an N-glycolylneuraminate, contains an N-acetylgalactosamine, contains a rhamnose, contains a glucuronate, contains a galacturonate, or contains an N-acetylmannosamine.

20. The method of claim 1, wherein the oligosaccharide mixture comprises charged, neutral, or a combination of charged and neutral oligosaccharides.

21. The method of claim 1, wherein the oligosaccharide mixture comprises fucosylated, non-fucosylated, or a combination of fucosylated and non-fucosylated neutral oligosaccharides.

22. The method of claim 1, wherein the oligosaccharide mixture comprises

at least one fucosylated oligosaccharide,

at least one sialylated oligosaccharide,

at least one oligosaccharide that comprises an N-acetylglucosamine monosaccharide unit, or

at least one galactosylated oligosaccharide.

23.-25. (canceled)

26. The method of claim 21, wherein all of the oligosaccharides in the mixture are fucosylated oligosaccharides.

27. The method of claim 1, wherein the cell produces three fucosylated oligosaccharides.

28. The method of claim 1, wherein the acceptors are produced by methods comprising extraction from natural sources, biotechnological processes, physical processes, chemical processes, or a combinations thereof.

29. The method of claim 1, wherein any one of the acceptors is completely converted into any one of the oligosaccharides.

30. The method of claim 1, wherein the cell produces the mixture of at least two oligosaccharides intracellularly and wherein a fraction or substantially all of the produced oligosaccharides remains intracellularly or is excreted outside the cell via passive or active transport.

31. The method of claim 1, wherein the cell is further metabolically engineered for

i) modified expression of an endogenous membrane protein,

ii) modified activity of an endogenous membrane protein,

iii) expression of a homologous membrane protein,

iv) expression of a heterologous membrane protein, or

v) a combination of i) to iv),

wherein the membrane protein is involved in: the secretion of any one of the oligosaccharides from the cell, or the uptake of a precursor for the synthesis of any one of the oligosaccharides of the mixture.

32. (canceled)

33. The method of claim 31, wherein the membrane protein comprises a porters, P-P-bond-hydrolysis-driven transporters, β-barrel porins, auxiliary transport proteins, putative transport proteins or phosphotransfer-driven group translocators,

wherein the porters comprises a MFS transporters, sugar efflux transporters or siderophore exporters,

wherein the P-P-bond-hydrolysis-driven transporters comprises an ABC transporters or siderophore exporters.

34. The method of claim 31, wherein the membrane protein provides improved production, or enabled or enhanced efflux of the mixture of at least two oligosaccharides.

35. The method of claim 1, wherein the cell resists the phenomenon of lactose killing when grown in an environment in which lactose is combined with one or more other carbon source(s).

36. The method of claim 1, wherein the cell comprises a modification for reduced production of acetate compared to a non-modified progenitor, optionally the cell comprises a lower or reduced expression, or abolished, impaired, reduced or delayed activity of one or more of proteins comprising beta-galactosidase, galactoside O-acetyltransferase, N-acetylglucosamine-6-phosphate deacetylase, glucosamine-6-phosphate deaminase, N-acetylglucosamine repressor, ribonucleotide monophosphatase, EIICBA-Nag, UDP-glucose:undecaprenyl-phosphate glucose-1-phosphate transferase, L-fuculokinase, L-fucose isomerase, N-acetylneuraminate lyase, N-acetylmannosamine kinase, N-acetylmannosamine-6-phosphate 2-epimerase, EIIAB-Man, EIIC-Man, EIID-Man, ushA, galactose-1-phosphate uridylyltransferase, glucose-1-phosphate adenylyltransferase, glucose-1-phosphatase, ATP-dependent 6-phosphofructokinase isozyme 1, ATP-dependent 6-phosphofructokinase isozyme 2, glucose-6-phosphate isomerase, aerobic respiration control protein, transcriptional repressor IclR, lon protease, glucose-specific translocating phosphotransferase enzyme IIBC component ptsG, glucose-specific translocating phosphotransferase (PTS) enzyme IIBC component malX, enzyme IIAGlc, beta-glucoside specific PTS enzyme II, fructose-specific PTS multiphosphoryl transfer protein FruA and FruB, ethanol dehydrogenase aldehyde dehydrogenase, pyruvate-formate lyase, acetate kinase, phosphoacyltransferase, phosphate acetyltransferase, or pyruvate decarboxylase compared to a non-modified progenitor.

37. (canceled)

38. The method of claim 1, wherein the cell is capable of producing phosphoenolpyruvate (PEP), or the cell is modified for enhanced production or supply of PEP compared to a non-modified progenitor.

39. (canceled)

40. The method of claim 1, wherein any one of the oligosaccharides is:

a mammalian milk oligosaccharide, or

an antigen of the human ABO blood group system.

41. (canceled)

42. The method of claim 1, wherein the cell is a bacterium, fungus, yeast, a plant cell, an animal cell, or a protozoan cell.

43. The method of claim 42, wherein the cell is a viable Gram-negative bacterium that comprises a reduced or abolished synthesis of poly-N-acetyl-glucosamine (PNAG), Enterobacterial Common Antigen (ECA), cellulose, colanic acid, core oligosaccharides, Osmoregulated Periplasmic Glucans (OPG), Glucosylglycerol, glycan, and/or trehalose compared to a non-modified progenitor.

44. The method of claim 1, wherein the separation comprises at least one of the following steps: clarification, ultrafiltration, nanofiltration, two-phase partitioning, reverse osmosis, microfiltration, activated charcoal or carbon treatment, treatment with non-ionic surfactants, enzymatic digestion, tangential flow high-performance filtration, tangential flow ultrafiltration, affinity chromatography, ion exchange chromatography, hydrophobic interaction chromatography, gel filtration, or ligand exchange chromatography.

45. The method of claim 1 further comprising purification of any one of the oligosaccharides from the cell, optionally the purification comprises at least one of the following steps: use of activated charcoal or carbon, use of charcoal, nanofiltration, ultrafiltration, electrophoresis, enzymatic treatment or ion exchange, use of alcohols, use of aqueous alcohol mixtures, crystallization, evaporation, precipitation, drying, spray drying, lyophilization, spray freeze drying, freeze spray drying, band drying, belt drying, vacuum band drying, vacuum belt drying, drum drying, roller drying, vacuum drum drying, or vacuum roller drying.

46.-47. (canceled)