Abstract: The subject of the invention is a process for extracting pure lactic acid from fermentation liquors by ion exchange chromatography on a strongly acidic cation exchanger, preferably in H.sup.+ form. In a first step, the NH.sub.4 lactate coming from the fermentation is converted into the free acid by genuine ion exchange. This conversion is preferably effected on a weakly acidic cation exchanger in H.sup.+ form.

Abstract: A reactor for carrying out biological reactions by means of biocatalysts includes a base which houses an agitator unit and suitable monitor and control devices and a securely attachable lid. Interposed between the lid and the base is an intermediate part in form of a vat which for application as fluid-bed reactor and/or fixed-bed reactor includes at its lower end a gas bubbles-permeable support for a biocatalyst-laden matrix or biocatalyst matrix. Extending from the upper area of the intermediate part toward the base is a circulation line which cooperates with the agitator unit which is designed as circulating pump.

Abstract: In a method of continuously producing ethanol from sugar-containing substrates by fermentation of sugars by means of a flocculating strain of Zymomonas mobilis under anaerobic conditions and at a pH of from 4.5 to 7 a substrate is led commonly with Zymomonas mobilis cells through at least three fermentation stages without preceding sterilization, a concentration of at least 4% by volume of ethanol is maintained in each fermentation stage, a residence time of the fermentation medium in the entire system of maximally 31/3 h corresponding to a dilution rate of the fermentation medium in the entire system of at least 0.3 h.sup.-1 is adjusted, the Zymomonas mobilis cells are separated by sedimentation after the final fermentation stage, the Zymomonas mobilis cells are recycled into the first fermentation stage, and the ethanol-containing substrate separated from the Zymomonas mobilis cells is drawn off.

Abstract: There is disclosed an arrangement for growing permanent forms, of microorganism in particular filaments microorganisms. In order to design such an arrangement operationally safe, mobile and compact and with a high adaptability, yet for ensuring sufficiently large production and manipulation surfaces, the arrangement, in which trays for the culture medium are superposed in a box-type container, further includes a feeding chamber and an air-conditioning chamber containing an air-conditioning device united in a common housing. A gas-tightly closeable feed opening is provided in a side wall of the feeding chamber. The air-conditioning device includes sterile filters for sterile-keeping intake air and for filtering offsteaming exhaust air.

Abstract: A membrane bag, a winding module and a method of making the membrane bag and winding module. The membrane bag and winding module comprise two separation membranes interconnected at their rims and having supply and drain conduits. The membrane bag and winding module are pressure tight and operationally safe at high pressures and temperatures. The rims of the separation membranes are flanged-in at least twice and glue layers are provided between superposed flange rims.

Abstract: A membrane separation arrangement includes a plurality of plate modules adjacently arranged in a housing, the plate modules being formed by two separation membranes each, which are interconnected at their rim regions so as to be tight all around, inner spacers formed by a layer of fibrous material being provided between said separation membranes.To reliably obtain tightness of the individual plate modules, with no high forces required for tightness acting on the separation membranes, while allowing the separation membranes to move without becoming damaged, outer spacers contacting the separation membranes and formed by a layer of fibrous material, such as a woven fabric, a knitted fabric or a nonwoven fabric, of organic or inorganic fibres, are provided between the individual plate modules, and the individual plate modules are interconnected via connection pieces sealingly inserted in openings of the separation membranes.

Abstract: A process for separating oxygenous organic compounds from aqueous media by liquid-liquid extraction with an organic extraction agent. In order to enable the satisfactory and selective separation of the organic compounds without remarkable amounts of extraction agent remaining dissolved in the raffinate and without microorganisms possibly present in the aqueous media being impaired, an extraction agent is used that contains up to 100% by mass of at least one aldehyde including 4 to 20 carbon atoms.

Abstract: A device for measuring volatile constituents of a culture medium in the fermentation industry, comprising a probe, which has a permeable membrane to exchange material for a carrier medium, and a sensor responding to the content of the substance to be measured which has permeated into the carrier medium. In order that the device may be used in industrial fermenters and in order to achieve a high degree of accuracy in measurement and reproducibility of the measured values, both the permeable membrane and the sensor are disposed in the space in which the culture medium to be tested is situated, the probe being introduced into the space containing the culture medium where appropriate by way of a lock.