Abstract: The present invention relates to a long-chain dibasic acid with low content of long-chain dibasic acid impurity of shorter carbon chain, to the preparation of a long-chain dibasic acid producing strain by directed evolution of POX gene and homologous recombination, and to the production of a long-chain dibasic acid with low content of long-chain dibasic acid impurity of shorter carbon chain by using the strain. The present invention also relates to a strain containing a mutated promoter, wherein, when a long-chain dibasic acid is produced by fermentation of this strain, the content of the acid impurity of shorter carbon chain in the fermentation product is significantly reduced.

Abstract: The present disclosure provides method for isolating a long chain dicarboxylic acid such as a substantially pure or pure long chain dicarboxylic acid from a fermentation broth containing microbial cells.

Abstract: The present invention discloses a method for producing a long chain dicarboxylic acid by fermentation as well as a fermentation broth, a treated fermentation broth and a wastewater. The salt content in the fermentation broth is controlled to be below 20% by the fermentation method of the present invention. The method for producing a long chain dicarboxylic acid by fermentation provided by the present invention can effectively reduce the amount of alkali used in the fermentation process and the amount of acid used in the subsequent extraction of the long chain dicarboxylic acid, thereby reducing the amount of salt in the whole production process of the long chain dicarboxylic acid. At the same time, the method of the present invention also has many advantages such as shortening the fermentation time, increasing the acid production, reducing the amount of medium, and suitable for the production of various types of long-chain dicarboxylic acids, etc.

Abstract: The present disclosure provides a system for extracting long chain dicarboxylic acid, the system comprising: a primary membrane filtration unit, a first crystallization unit, a first separation unit, a first dissolution tank, a secondary membrane filtration unit, a second separation unit, a second crystallization unit and a third separation unit. By the system for extracting long chain dicarboxylic acid of an embodiment of the present invention, the resulted long chain dicarboxylic acid product has a high purity, very low and even no residual alkane residue, and organic solvent-free.

Abstract: The present disclosure provides a method for extracting long chain dicarboxylic acid, the method comprising: (1) subjecting a long chain dicarboxylic acid fermentation broth to a primary membrane filtration treatment to give a first filtrate; subjecting the first filtrate to decolorization, crystallization, and solid-liquid separation to give a first solid; (2) redissolving the first solid in water to form a solution; subjecting the solution to decolorization, crystallization by acidification, and solid-liquid separation to give a second solid. By the method, the resulted long chain dicarboxylic acid product has a high purity and no residual organic solvent.

Abstract: The present disclosure provides a system for refining long chain dicarboxylic acid, comprising: a first membrane filtration unit, for a first membrane filtration of a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom; a first decolorization unit, for carrying out a first decolorization treatment to the filtrate obtained after the membrane filtration; a first acidification/crystallization unit, for carrying out a first acidification/crystallization of a filtrate obtained after the membrane filtration to give a solid-liquid mixture; a first separation unit, for a solid-liquid separation of the solid-liquid mixture; a drying unit, for drying the solid separated by the separation unit to give a first solid. By using the refining system according to the present disclosure, the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.

Abstract: One aspect provided herein relates to lysine decarboxylase polypeptides comprising mutants of SEQ ID NO: 2 (i.e., mutants of Klebsiella oxytoca (K. oxytoca) Ldc) and/or fragments thereof. In certain embodiments, the mutants or fragments thereof may have at least about 95% sequence identity with SEQ ID NO: 2. Another aspect provided herein relates to a DNA polynucleotide comprising one or more lysine decarboxylase nucleotide sequences of mutants of SEQ ID NO: 1 (i.e., mutants of K. oxytoca ldc), fragments thereof, or fragments of SEQ ID NO: 1 (i.e., fragments of K. oxytoca ldc). In certain embodiments, the DNA polynucleotide as disclosed herein may encode one or more lysine decarboxylase polypeptides provided herein. In certain embodiments, the DNA polynucleotide as disclosed herein may encode SEQ ID NO: 2, mutants, and/or fragments thereof. In certain embodiments, the lysine decarboxylase nucleotide sequences provided herein may have at least 95% sequence identity with SEQ ID NO: 1 or SEQ ID NO: 3.

Abstract: The present disclosure provides a method and a system for extracting long chain dicarboxylic acid, the method comprising: (1) subjecting a long chain dicarboxylic acid fermentation broth to a primary membrane filtration treatment to give a first filtrate; subjecting the first filtrate to decolorization, acidification/crystallization, and solid-liquid separation treatments to give a first solid; (2) mixing the first solid, a base and water to form a solution; subjecting the solution to a secondary membrane filtration treatment to give a second filtrate; subjecting the second filtrate to decolorization, acidification/crystallization, and solid-liquid separation treatments to give a second solid; and (3) mixing the second solid and water to form a mixture; subjecting the mixture to a thermostatic treatment at 105-150° C., followed by cooling for crystallization and solid-liquid separation treatment.

Abstract: The invention relates to a long-chain dibasic acid with low content of monobasic acid impurity and a production method thereof, in particular to the preparation of a long-chain dibasic acid producing strain by means of directed evolution and homologous recombination, and to the production of a long-chain dibasic acid with low content of monobasic acid impurity by fermentation of said strain. The invention relates to a mutated CYP52A12 gene, homologous gene or variant thereof, which, relative to GenBank Accession Number AY230498 and taking the first base upstream of the start codon ATG as ?1, comprises a mutation. The invention relates to a strain comprising said mutated CYP52A12 gene, homologous gene or variant thereof wherein when the strain is fermented to produce a long-chain dibasic acid, the content of monobasic acid impurity in the fermentation product is significantly reduced.

Abstract: The invention is directed to a method of preparing a long chain dicarboxylic acid producing strain by using directed evolution and homologous recombination, a strain obtained by this method that is capable of producing a long chain dicarboxylic acid under an acidic condition and the use of the strain. In particular, the invention is directed to a method of preparing a long chain dicarboxylic acid producing strain by using directed evolution of CYP52A12 gene and homologous recombination, a strain obtained by this method that is capable of producing a long chain dicarboxylic acid under an acidic condition and the use of the strain.

Abstract: The invention provides microorganisms genetically modified to overexpress thermophilic lysine decarboxylase polypeptides in a mesophilic host to enhance the production of lysine and lysine derivatives by the microorganism, method of generating such microorganism, and methods of producing lysine and lysine derivatives using the genetically modified microorganisms.

Abstract: The present disclosure provides a method and a system for refining long chain dicarboxylic acid, said method comprising the following steps: (1) subjecting a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom to a membrane filtration, an acidification/crystallization, a solid-liquid separation and drying to give a long chain dicarboxylic acid crude product; (2) subjecting the long chain dicarboxylic acid crude product to a vacuum distillation to give the long chain dicarboxylic acid product; wherein the pressure in the vacuum distillation is ?100 Pa. By using the refining method according to the present disclosure, the procedure is simplified, and the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.

Abstract: The present invention relates to a long-chain dibasic acid with low content of hydroxyl acid impurity and a production method thereof, in particular to a method for producing a long-chain dibasic acid with low content of hydroxyl acid impurity by fermenting a long-chain dibasic acid producing strain prepared by homologous recombination method. The present invention relates to a recombinant long-chain dibasic acid producing microorganism, having increased alcohol dehydrogenase activity and optionally decreased acyl-CoA oxidase activity. The present invention also relates to a method of producing a long-chain dibasic acid by the recombinant long-chain dibasic acid producing microorganism and use thereof.

Abstract: The invention provides microorganisms genetically modified to co-overexpress a carbohydrate binding module and lysine decarboxylase polypeptides in a mesophilic host to enhance the production of lysine derivatives by the microorganism, method of generating such microorganism, and methods of producing lysine derivatives using the genetically modified microorganisms.

Abstract: One aspect of the invention relates to a mutant polypeptide comprising the amino acid sequence of Escherichia coli tetracycline efflux pump A (TetA). Another aspect of the invention relates to a polynucleotide encoding a polypeptide of TetA, a fragment thereof, or a mutant thereof. Another aspect of the invention relates to a first expression plasmid vector comprising one or more first polynucleotides encoding a first polypeptide comprising a tetracycline efflux pump polypeptide, a fragment thereof or a mutant thereof, one or more second polynucleotides independently selected from the group consisting of a third polynucleotide encoding a third polypeptide comprising a lysine decarboxylase polypeptide, a fragment thereof or a mutant thereof, and a fourth polynucleotide encoding a fourth polypeptide comprising a lysine biosynthesis polypeptide, a fragment thereof or a mutant thereof.

Abstract: The invention relates to the directed evolution of CYP52A12 gene and the use thereof for the production of a dicarboxylic acid. In particular, it relates to a method of preparing a long chain dicarboxylic acid producing strain by using directed evolution and homologous recombination, a strain obtained by the method that is capable of producing a long chain dicarboxylic acid under an acidic condition and the use thereof. In particular, the invention relates to a method of preparing a long chain dicarboxylic acid producing strain by directed evolution of CYP52A12 gene and homologous recombination, a strain obtained by the method that is capable of producing a long chain dicarboxylic acid under an acidic condition and the use thereof. By directed evolution of CYP52A12 gene, one strain which has a base mutation at the promoter region of said gene and is capable of producing a long chain dicarboxylic acid under an acidic condition in a shortened fermentation time is screened out in the invention.

Abstract: The invention provides CadA polypeptides with mutations that increase activity in alkaline pH compared to the wild-type lysine decarboxylase. The invention also provides methods of generating such mutant polypeptides, microorganisms genetically modified to overexpress the mutant polypeptides, and methods of generating such microorganisms.

Abstract: The present disclosure provides a method and a system for extracting long chain dicarboxylic acid, the method comprising: (1) subjecting a long chain dicarboxylic acid fermentation broth to a primary membrane filtration treatment to give a first filtrate; subjecting the first filtrate to decolorization, acidification/crystallization, and solid-liquid separation treatments to give a first solid; (2) mixing the first solid, a base and water to form a solution; subjecting the solution to a secondary membrane filtration treatment to give a second filtrate; subjecting the second filtrate to decolorization, acidification/crystallization, and solid-liquid separation treatments to give a second solid; and (3) mixing the second solid and water to form a mixture; subjecting the mixture to a thermostatic treatment at 105-150° C., followed by cooling for crystallization and solid-liquid separation treatment.

Abstract: The present disclosure provides a method and a system for refining long chain dicarboxylic acid, said method comprising the following steps: (1) subjecting a long chain dicarboxylic acid fermentation broth or a treated liquid therefrom to a membrane filtration, an acidification/crystallization, a solid-liquid separation and drying to give a long chain dicarboxylic acid crude product; (2) subjecting the long chain dicarboxylic acid crude product to a vacuum distillation to give the long chain dicarboxylic acid product; wherein the pressure in the vacuum distillation is ?100 Pa. By using the refining method according to the present disclosure, the procedure is simplified, and the purity of the obtained product is high, and the disadvantages such as poor quality of the product obtained by crystallization from a solvent and environment pollution caused by a solvent can be overcome.

Abstract: The invention provides CadA polypeptides with mutations that increase activity in alkaline pH compared to the wild-type lysine decarboxylase. The invention also provides methods of generating such mutant polypeptides, microorganisms genetically modified to overexpress the mutant polypeptides, and methods of generating such microorganism.