Abstract: In various aspects and embodiments, the invention provides a nucleic acid molecule comprising a nucleotide sequence encoding a 7?-hydroxysteroid dehydrogenase (7?-HSDH) mutant that catalyzes at least the stereospecific enzymatic reduction of a 7-ketosteroid to the corresponding 7-hydroxysteroid, wherein the mutant has, compared to the wildtype 7?-HSDH of SEQ ID NO:2, a decreased substrate inhibition and/or an altered cofactor usage, and the mutant has, in comparison with the wildtype 7?-HSDH of SEQ ID NO:2, 1 to 15 amino acid additions, substitutions, deletions and/or inversions in the sequence motif VMVGRRE corresponding to positions 36 to 42 of SEQ ID NO:2.

Abstract: The invention relates to novel 7ß-hydroxysteroid dehydrogenase mutants, to the sequences which encode these enzyme mutants, to processes for the preparation of the enzyme mutants and to their use in enzymatic reactions of cholic acid compounds, in particular in the preparation of ursodeoxycholic acid (UDCS). The invention also relates to novel processes for the synthesis of UDCS using the enzyme mutants; and to the preparation of UDCS using recombinant, multiply-modified microorganisms.

Abstract: The invention relates to novel biocatalytic processes comprising the whole cell reduction of dehydrocholic acid (DHCA) compounds, novel 7?-hydroxy steroid dehydrogenase mutants, the sequences coding for these enzyme mutants, methods for producing the enzyme mutants and use thereof in enzymatic conversions of cholic acid compounds, and in particular in the production of ursodesoxycholic acid (UDCA); also a subject of the invention are novel methods for the synthesis of UDCA using the enzyme mutants; and in particular a further improved method for producing UDCA using recombinant whole cell biocatalysts.

Abstract: The invention relates to novel biocatalytic processes comprising the whole cell reduction of dehydrocholic acid (DHCA) compounds, novel 7?-hydroxy steroid dehydrogenase mutants, the sequences coding for these enzyme mutants, methods for producing the enzyme mutants and use thereof in enzymatic conversions of cholic acid compounds, and in particular in the production of ursodesoxycholic acid (UDCA); also a subject of the invention are novel methods for the synthesis of UDCA using the enzyme mutants; and in particular a further improved method for producing UDCA using recombinant whole cell biocatalysts.

Abstract: The invention relates to novel 7?-hydroxysteroid dehydrogenase mutants, to the sequences which encode these enzyme mutants, to processes for the preparation of the enzyme mutants and to their use in enzymatic reactions of cholic acid compounds, in particular in the preparation of ursodeoxycholic acid (UDCS). The invention also relates to novel processes for the synthesis of UDCS using the enzyme mutants; and to the preparation of UDCS using recombinant, multiply-modified microorganisms.

Abstract: The invention relates to 12 ?-hydroxysteroid dehydrogenases, nucleic acid sequences coding for the same, expression cassettes and vectors, recombinant microorganisms containing the corresponding coding nucleic acid sequences, a method for producing said 12 ?-hydroxysteroid dehydrogenases, a method for enzymatic oxidation of 12 ?-hydroxysteroids using said enzyme, a method for enzymatic reduction of 12-ketosteroids using said enzyme, a method for qualitative or quantitative determination of 12-ketosteroids and/or 12?-hydroxysteroids using said 12?-hydroxysteroid dehydrogenases and a method for production of ursodesoxycholic acid, comprising the enzyme-catalyzed cholic acid oxidation using said 12 ?-hydroxysteroid dehydrogenases.

Abstract: The invention relates to novel 7?-hydroxysteroid dehydrogenase mutants, to the sequences which encode these enzyme mutants, to processes for the preparation of the enzyme mutants and to their use in enzymatic reactions of cholic acid compounds, in particular in the preparation of ursodeoxycholic acid (UDCS). The invention also relates to novel processes for the synthesis of UDCS using the enzyme mutants; and to the preparation of UDCS using recombinant, multiply-modified microorganisms.

Abstract: The invention relates to novel microbial 7?-hydroxysteroid dehydrogenase (7?-HSDH) knockout mutants and to the use thereof for producing other HSDHs having various functionalities, such as 3?-, 7?- or 12?-HSDH, and to the use of thus-produced HSDH enzymes in enzymatic reactions of cholic acid compounds, and in particular for producing ursodeoxycholic acid (UDCS). The invention relates in particular to novel methods for synthesizing UDCS.

Abstract: Cavitation reactor for hydrodynamic generation of homogeneous, oscillating cavitation bubbles in a fluid, including, while forming a flow duct and arranged one behind the other in the direction of flow of the fluid, an acceleration section designed to increase a flow velocity, a diaphragm arranged transversely to the direction of flow with a plurality of micro-passages designed for generating cavitation bubbles, where at least 10 micro-passages per cm2 are provided over an entire flow cross-sectional surface defined on an oncoming flow side of the diaphragm, a stabilization section designed for stabilizing an oscillation of cavitation bubbles, and a collapse section with at least one widening of a flow cross-sectional surface of the flow duct in the direction of flow.

Abstract: The invention relates to a method for producing a body (7) comprising cellulose with the help of cellulose-producing organisms, which are supplied with a nutrient solution. A particularly uniform structure and density of the cellulose bodies can be achieved when a vessel (1) having a membrane (4) is supplied, said membrane being permeable to the nutrient solution and is substantially impermeable to the organisms, wherein the organisms are cultivated on one side of the membrane (4), where a gas atmosphere prevails, and the nutrient solution is arranged on the other side of the membrane and passes through the membrane (4) in the direction of the organisms, to supply them.

Abstract: Disclosed herein are embodiments of a sampling system for fluid samples having sample receiving vessel for receiving the sample, which is sealed by a septum and holder for the sample receiving vessel for receiving and holding the sample receiving vessel and also a sample probe for dipping into a fluid volume and for taking a fluid sample from the fluid volume, the sample probe being configured as a hollow volume which, at one end, has a first opening for introducing the holder and the sample receiving vessel and, at another end, is sealed by a first valve which is provided with a hollow needle which projects into the interior of the sample probe said valve being able to be opened by contact with at least one of the group comprising the holder and the sample receiving vessel and then connecting the exterior of the sample probe to the inner volume of the hollow needle.

Abstract: The present invention relates to a sampling system for fluid samples having sample receiving vessel for receiving the sample, which is sealed by a septum and holder for the sample receiving vessel for receiving and holding the sample receiving vessel and also a sample probe for dipping into a fluid volume and for taking a fluid sample from the fluid volume, the sample probe being configured as a hollow volume which, at one end, has a first opening for introducing the holder and the sample receiving vessel and, at another end, is sealed by a first valve which is provided with a hollow needle which projects into the interior of the sample probe said valve being able to be opened by contact with the holder and/or with the sample receiving vessel and then connecting the exterior of the sample probe to the inner volume of the hollow needle.

Abstract: The invention relates to a device for the cultivation of cells in liquid columns measured on a millimetre scale. Said device comprises a container for receiving a liquid culture suspension of the cells, a mixing element for mixing the culture suspension in the container around a mixing axis. The container and/or the mixing element are configured in such a manner that the speed of the flow is modified either locally and/or temporally along a streamline or flow line around the mixing axis.

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: 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: 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: The invention relates to a method and a device for series cultivation of organisms which is particularly suitable for providing organisms to be cultivated with a culture medium that has a toxic effect on said organisms at a high dosage, but when applied in appropriate dosage, said device determines the amount of substrate required to enable organisms to produce substances microbially in optimum conditions. According to the invention, a dosing schedule is predefined and the amount of substrate in the flask is adjusted according to actual requirements. In order to avoid underdosage, filling of the shaking flask no longer occurs according to a fixed predefined sequence.

Abstract: A reaction apparatus has a plurality of reaction flasks whose bottoms can communicate with a sterile gas source and are provided with porous filter plates which permit the gas to flow into the vessel but prevent the liquid from passing out through the plates. The culture flasks are received in pockets on an upper plate of a double-bottom structure which can communicate through the upper plate between a space within the double bottom and the bottom of the culture flasks. The spiral gas feed is connected to the double-bottom space.