Abstract: The invention concerns a method for culturing cells in order to produce substances. According to the invention a cell line producing substances is cultured while feeding a nutrient medium in such a manner that glucose limitation occurs in the culture solution. The degree of glucose limitation DGL=qGlc/qGlcmax (qGlc=observed current specific glucose consumption rate; qGlcmax=maximum known specific glucose consumption rate for these cells). DGL is between the limits 0 and 1, where 0 means complete limitation and 1 means no limitations or complete glucose excess. According to the invention DGL is larger or equal to the DGL which only leads to the maintenance of the cell and ?0.5.

Abstract: The present invention relates to a process for integrated removal of one or more organic substances present in an aqueous bioprocess mixture, which comprise at least one positively charged and/or chargeable nitrogen-containing group, by means of reactive extraction in at least one step, in which process at least one liquid-liquid centrifuge is used for said reactive extraction and said organic substances are re-extracted from the extractant into an aqueous phase. More specifically, the bioprocess mixture directed to the liquid-liquid centrifuges is rendered cell-free and protein-free, before being directed into the first centrifuge. Furthermore, the invention relates to such a process in which an aqueous bioprocess mixture is continuously removed from a bioreactor, led, with an extractant, into a liquid-liquid centrifuge, extracted by means of said extractant, with an organic phase being obtained which contains the substance to be extracted from the fermentation mixture.

Abstract: The invention concerns a method for culturing cells in order to produce substances. According to the invention a cell line producing substances is cultured while feeding a nutrient medium in such a manner that glucose limitation occurs in the culture solution. The degree of glucose limitation DGL=qGlc/qGlcmax (qGlc=observed current specific glucose consumption rate; qGlcmax=maximum known specific glucose consumption rate for these cells). DGL is between the limits 0 and 1, where 0 means complete limitation and 1 means no limitations or complete glucose excess. According to the invention DGL is larger or equal to the DGL which only leads to the maintenance of the cell and ?0.5.

Abstract: The present invention relates to a process for the kinetic resolution of racemic functionalized epoxides in the presence of microorganisms, crude or pure preparations thereof comprising a polypeptide having epoxide hydrolase activity. Preferred microorganisms are yeasts and bacteria which may also be recombinant.

Abstract: The invention relates to a process for the production of an aromatic amino acid metabolite or derivative thereof by aerobic fermentation of Escherichia coli, which fermentation comprises a growth and a production phase and in which fermentation glucose and L-tyrosine are controlled, wherein during at least part of the production phase, the glucose concentration in the fermentation medium is controlled within the range of 1-20 g/L and the L-tyrosine concentration in the fermentation medium is controlled below 36 mg/L.

Abstract: The present invention relates to a process for separating from an aqueous mixture one or more organic substances containing at least one positively charged and/or chargeable nitrogenous group by means of extraction via at least one porous membrane, wherein use is made of an extraction agent which contains at least partially relatively long-chain organic compounds and at least one liquid cation exchanger, and of a membrane that is wettable by either the aqueous mixture or by the extraction agent.

Abstract: The first embodiment of the present invention provides a process, which includes: in a continuous process in a membrane reactor, asymmetrically hydrogenating at least one C═C, C═N or C═O double bond with a catalyst. Another embodiment of the present invention provides a ligand, which includes at least one di-1,3-aminophosphine homochiral active center; optionally, a linker; and a molecular weight-enlarging polymer; wherein the active center is bound to the molecular weight-enlarging polymer through the linker or is bound directly to the molecular weight-enlarging polymer; and wherein the linker is defined in the claims. Another embodiment of the present invention provides a process for preparing the above-noted ligand, and a catalyst that includes the above-noted ligand.

Abstract: A method for determining substrate and product concentration in liquid and/or gaseous media is disclosed. The analytes are removed by time-controlled diffusion of at least one analyte between the medium and a diffusion medium which is fed to the sampling regions through fluid conduits using at least one pump and semipermeable membranes. The diffusion medium is transported to at least one detector, while simultaneously new diffusion medium is fed from the sampling region and analyzed to determine the analyte concentration. The pump operates continuously and the diffusion medium is fed to the fluid conduits in alternation through a multivalve or multipath valve connected in series upstream from the sampling regions. The detector and the pump are additionally connected through a bypass conduit joined to the valve, and the detector is continuously fed diffusion medium through the fluid conduits and the bypass conduit.

Abstract: In a method of reducing diketocarboxylic acids or hydroxyketocarboxylic acids or their esters, at least one keto group is converted to a hydroxyl group in the presence of lactobacillus species.

Abstract: The present invention relates to a process for the kinetic resolution of racemic functionalized epoxides in the presence of microorganisms, crude or pure preparations thereof comprising a polypeptide having epoxide hydrolase activity. Preferred microorganisms are yeasts and bacteria which may also be recombinant.

Abstract: A method for determining substrate and product concentration in liquid and/or gaseous media is disclosed. Several samples of at least one substance to be analyzed are removed in at least one sampling region by time-controlled diffusion of the analyte between the medium and a diffusion medium, which is fed to the sampling regions through fluid conduits using at least one pump and semipermeable membranes. The diffusion medium is transported to at least one detector while simultaneously new diffusion medium is fed from the sampling region, and analyzed to determine the analyte concentration. The detector provides a temporal concentration distribution or a temporal distribution of a signal proportional to the concentration. A change in the ratio of the signal maximum to the base line is ascertained in the output of the detector signal and, on the basis of this, a change in the diffusion properties of the semipermeable membrane is inferred and a correction factor ascertained.

Abstract: The present invention relates to a process for separating from an aqueous mixture one or more organic substances containing at least one positively charged and/or chargeable nitrogenous group by means of extraction via at least one porous membrane, wherein use is made of an extraction agent which contains at least partially relatively long-chain organic compounds and at least one liquid cation exchanger, and of a membrane that is wettable by either the aqueous mixture or by the extraction agent.

Abstract: In a method of reducing diketocarboxylic acids or hydroxyketocarboxylic acids or their esters, at least one keto group is converted to a hydroxyl group in the presence of lactobacillus species.

Abstract: Furanosides or pyranosides can be reacted with pyruvate and converted into sialic acids in good yields by an enzymatic synthesis, using a suitable aldolase, where the concentration of aldolase, per 50 mM of pyruvate, is 1 to 2,500 U*/ml. For example, 3-fluoroneuraminic acid and other 3,3-didesoxy-3-fluorononulopyranosonic acid derivatives can be prepared in this manner. The F-atom in the resulting sialic acid (which can be 19F or 19F and 18F) provides a label which makes possible studies of mammalian physiology and diagnosis of mammalian diseases.

Abstract: The first embodiment of the present invention provides a process, which includes:

Abstract: A process for producing citric acid/citrate for use in producing citric acid, comprising the steps of continuously feeding to a fermenter containing a yeast capable of transforming glucose to citric acid by fermentation, in the presence of a nutrient medium and oxygen, sugar, especially glucose as a C source and at least one ammoniun compound as an N source fermenting the sugar to citric acid in said fermenter at a temperature, a pH and with a residence time sufficient to transform at least a major part of the sugar continuously fed to said fermenter to citric acid continuously withdrawing fermentation product from said fermenter recovering citric acid/citrate from said fermentation product controlling a C/N ratio fed to said fermenter to correspond to a molar ratio of glucose to ammonium compounds of 12 to 22 during fermentation of the glucose to citrate.

Abstract: The invention involves a procedure for the catalytic enantioselective reduction of ketones to chiral alcohols. Heretofore, this reaction was carried out batch-wise. Because, in this procedure, one utilizes a catalyst increased in size with polymer, it is possible to carry out the reaction in a quasi-continuous manner in a membrane reactor. In contrast to the state of the art, one thus dramatically increases the operative life of the catalyst.

Abstract: Strains of Aureobasidium pullulans (de bary) Arnaud can be used for the commercial production of gluconic acid by fermentation in aqueous liquid containing sugar, which in continuous culture from glucose form greater than or equal to 90% and greater than or equal to 90% molar selectivity. The process is conducted with an Fe and Mn optimized medium with a nitrogen-independent (N-independent) ion concentration. The iron (Fe) concentration with 3 g/l NH.sub.4 Cl is greater than or equal to 0.5 mM, and the manganese (Mn) concentration with 3 g/l NH.sub.4 Cl is greater than or equal to about 0.5 mM manganese (Mn). The pH is regulated between about 4.5 and about 8, in particular at 6.5-7, and the temperature between 24 and 32.degree. C., in particular at 29-30.degree. C. Particularly successful strains are Aureobasidium pullulans (de bary) Arnaud with the registration numbers DSM 7085, DSM 7086, DSM 7087, and DSM 7088.

Abstract: Stem cells or other organ-function cells are cultivated in a fluidized bed system on macroporous glass carrier bodies treated with a structure protein such as gelatin and an extracellular matrix protein such as fibronectin, and coated with a stroma cell layer. Glass carriers coated with gelatin are added to a fluidized bed reactor, and a culture medium containing an extracellular matrix protein is added to bind the protein to the gelatin. Stromal cells are then added and the cells are cultured to immobilize the cells on the carriers containing the bound protein. Immature organ-function cells are added to the reactor, and while generating a fluidized bed of the carriers in the culture medium, the culture medium is recirculated from and to the reactor in a recirculation loop. Bubble-free aeration of the culture medium is effected to cultivate the immature organ-function cells on the carriers to obtain both mature differentiated organ-function cells and progenitor organ-function cells.

Abstract: In a process for the continuous enzyme-catalyticzed enzymatic production of hydrophobic products in an aqueous solution of a reaction mixture, the product is extracted from the product containing reaction mixture by way of a product-permeable microporous membrane into an organic solvent and the product-depleted reaction mixture is recycled.