Abstract: A novel class of bioreactor apparatuses are disclosed which offer improved performance over prior art designs. The apparatuses circulate nutrient fluid through a bioreactor device, such as a hollow fiber bioreactor cartridge, which is used to culture a colony of cells. The nutrient fluid is refreshed by the controlled addition of fresh fluid and the controlled removal of used fluid through a sterile infusion/extraction device. Cellular by-product yield is enhanced by periodically alternating the direction of nutrient fluid through the bioreactor and by periodically circulating the harvest fluid through the extracapillary region of the bioreactor cartridge.

Abstract: A continuous process of optimized fermentation of sugars for the production of alcohol is disclosed, which comprises the following process steps and operational conditions:(a) continuously feeding a wort with a controlled concentration of sugars in the range of 100 to 160 g/l into one or more fermentation vessels arranged in parallel and containing a culture with a concentation of yeast cells in the range of 10.sup.11 to 10.sup.12 cells per liter, and completely stirring the fermentation medium;(b) controlling the conditions of the fermentation medium by fixing the temperature in the range of 30.degree. to 39.degree. C. and the pH in the range of 3.2 to 4.

Abstract: A process for producing ethanol in the substantial absence of fusel oils by Zymomonas fermentation wherein fermentation is carried out under conditions unfavorable for the growth and replication of yeast. In the preferred embodiment, Zymomonas are initially inoculated into a carbohydrate containing medium undergoing active fermentation by yeast, then the fermentation conditions altered to inhibit growth and replication of yeast.

Abstract: A process for converting AMP into ATP which comprises (a) using an enzyme which converts AMP into ADP and has been produced from microorganisms having an optimum growth temperature of 50.degree. C. to 85.degree. C. and an enzyme which converts ADP into ATP and has been produced from microorganisms having an optimum growth temperature of 50.degree. to 85.degree. C. is disclosed. In addition, there is disclosed a process for producing a physiologically active substance by a multienzyme process which comprises forming ATP from AMP by the step (a), (b) synthesizing a physiologically active substance with the resulting ATP, coverting AMP resulting from the reaction in step (b) into ATP by the reaction in step (a), and repeatedly utilizing the converted ATP for synthesis of the physiologically active substance in step (b). By using the process it is possible to stably and efficiently carry out conversion of AMP into ATP over a long period of time.

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: A process for producing a variety of chemical products, e.g., ethanol, by fermentation in which the product is removed from the fermentation medium as it is formed by liquid-liquid extraction using an extractant for the product which is immiscible with water. The extractant employed is chosen from the following groups: (A) double bond unsaturated aliphatic alcohols having 12 or more carbon atoms; (B) saturated branched chain aliphatic alcohols having 14 or more carbon atoms or mixtures thereof; (C) double bond unsaturated aliphatic acids having 12 or more carbon atoms; (D) aliphatic and aromatic mono-, di- or tri-esters having 12 or more carbon atoms, other than dibutyl phthalate; (E) aliphatic noncyclic ketones and aliphatic aldehydes having 12 or more carbon atoms; and (F) mixtures of extractants from groups (A) to (E) above or mixtures of at least one of the above extractants and at least one other extractant.

Abstract: The present invention relates to a continuous process for the enzymatic preparation of isomaltulose. A periplasmatic sucrose-mutase is produced by fermentation of microorganisms which form sucrose-mutase. The cell-free crude enzyme extract is prepared by digestion of the cells and by cross-flow microfiltration. In a single-stage, simultaneous purification and immobilization of the sucrose-mutase from the cell-free crude extract conditioned by diafiltration is obtained by selective bonding to an anionizable carrier matrix. Direct conversion of sucrose into isomaltulose is produced by the sucrose-mutase bonded to the anionizable carrier matrix, preferably in cartridge or cartouche form.

Abstract: Low aliphatic alcohols or organic solvents, especially ethanol are continuously produced by fermentation from sugar containing nutrient substrates. The process includes two fermentation steps or stages in which the substrate is subjected to the effects of microorganisms such as yeast. The first fermentation stage has a volume of 10 to 20% of that of the second fermentation stage. By adjusting the environmental conditions in each stage a large cell growth with a small portion of the total supplied substrate quantities takes place in the first activation stage and a high product formation rate is achieved with a considerably larger portion of the entire supplied substrate quantity in the second production stage. A partial outflow stream from the first stage is microfiltered and the permeate as well as the unfiltered outlet flow of the first stage, is directed into the second stage.

Abstract: A continuous process for the production of ethanol by fermentation of an organism of the genus Zymomonas is provided. The method is carried out by cultivating the organism under substantially steady state, anaerobic conditions and under conditions in which ethanol production is substantially uncoupled from cell growth. By controlling pH in the fermentation medium between a pH of about 3.8 and a pH less than 4.5, it is possible to optimize kinetic parameters, such as q.sub.s (g substrate/g biomass-hr.sup.-1) and q.sub.p (g ethanol/g biomass-hr.sup.-1) without adversely affecting ethanol concentration in the fermentation medium.

Abstract: A method of producing Trichoderma conidia in submerged culture comprises first preparing an inoculant of a desired strain of Trichoderma. Then, the inoculum is placed in a sufficient volume of a suitable liquid medium. The medium is maintained under substantially constant illumination, agitation and aeration at a temperature from about 25.degree. C. to about 30.degree. C., and a pH from about 5.8 to about 7.0. The culture is grown from a sufficient period of time until the density of conidia is about 5.0.times.10.sup.8 per ml, and then the conidia so produced are harvested. A similar method is provided for the production of Trichoderma chlamydospores.

Abstract: This invention provides a semi-continuous fermentation process which is operated in a repeated fed-batch mode to maintain cell bioconversion productivity at a high level without product inhibition of enzymatic activity. The process is illustrated by the bioconversion of toluene or catechol via the ortho pathway to muconic acid which accumulates in the fermentation medium in a quantity up to about 50 grams per liter.

Abstract: A formate salt is used as part of the fermentable carbon-containing material in an anaerobic fermentation to produce acetic acid. Acetate salt formed in the fermentation is converted to free acetic acid with formic acid, which in turn is changed to formate salt. This formate salt then is used as a carbon source for another fermentation.

Abstract: The present invention is directed to the preparation of ethanol by bacterial fermentation. It makes use of a microorganism capable of producing ethanol and the process is carried out in two stages. In the first stage a bacterial cell suspension is produced together with ethanol in an ethanol concentration range that does not substantially inhibit production of the bacterial cells in a medium containing a source of nitrogen and a source of carbon. Ethanol is then produced in the absence of substantial bacterial cell production by the addition of fermentable sugar to the bacterial cell suspension which is produced in the first stage. The preferred microorganism is a member of the genus Zymomonas.

Abstract: A continuous process for the production of ethanol by fermentation with strains of Zymomonas is provided. Metabolic processes are limited by the nutrients nitrogen, potassium and phosphorus. When growth is limited by one of these nutrients, the biomass expresses its maximum value for both q.sub.s and q.sub.p at any given value of D and S.sub.r. The process is conducted at a lower biomass concentration and a higher specific rate of ethanol formation than a similar process conducted with a nutrient medium that is not limited in nitrogen, potassium or phosphorus. A method of improving performance of Zymomonas in continuous ethanol fermentation at increased temperatures is also provided.

Abstract: A continuous process for the production of ethanol by fermentation with strains of Zymomonas is provided. Metabolic processes are limited by the nutrients nitrogen, potassium and phosphorus. When growth is limited by one of these nutrients, the biomass expresses its maximum value for both q.sub.s and q.sub.p at any given value of D and S.sub.r. The process is conducted at a lower biomass concentration and a higher specific rate of ethanol formation than a similar process conducted with a nutrient medium that is not limited in nitrogen, potassium or phosphorus. A method of improving performance of Zymomonas in continuous ethanol fermentation at increased temperatures is also provided.

Abstract: A continuous process for the production of ethanol by fermentation with strains of Zymomonas is provided. Metabolic processes are limited by the nutrients nitrogen, potassium and phosphorus. When growth is limited by one of these nutrients, the biomass expresses its maximum value for both q.sub.s and q.sub.p at any given value of D and S.sub.r. The process is conducted at a lower biomass concentration and a higher specific rate of ethanol formation than a similar process conducted with a nutrient medium that is not limited in nitrogen, potassium or phosphorus. A method of improving performance of Zymomonas in continuous ethanol fermentation at increased temperatures is also provided.

Abstract: A continuous process for the production of ethanol by fermentation with strains of Zymomonas is provided. Metabolic processes are limited by the nutrients nitrogen, potassium and phosphorus. When growth is limited by one of these nutrients, the biomass expresses its maximum value for both q.sub.s and q.sub.p at any given value of D and S.sub.r. The process is conducted at a lower biomass concentration and a higher specific rate of ethanol formation than a similar process conducted with a nutrient medium that is not limited in nitrogen, potassium or phosphorus. A method of improving performance of Zymomonas in continuous ethanol fermentation at increased temperatures is also provided.

Abstract: A high-density fermentation process for high yield production of swine growth hormone by transformant E. coli is described. The process employs transformant strains of E. coli containing an expression vector coding for swine growth hormone under the control of a bacteriophage lambda promoter-operator and an expression vector coding for the cI857 temperature-sensitive repressor protein. In the initial growth period, the level of dissolved oxygen in the fermentation medium is maintained at about 20% to 60% saturation and the temperature of the medium is kept between 26.degree. C. and 30.degree. C. Production of swine growth hormone is then induced by raising the temperature of the medium to about 42.degree. C. The temperature is then reduced to about 40.degree. C. to optimize cell growth for the remainder of the induction period, during which the level of dissolved oxygen in the medium is maintained at about 10% to 40% saturation.

Abstract: Catalytic chemical and biochemical conversion reactions are carried out in a novel compartmentalized catalytic reactor which enables the energy-efficient coupling of the conversion reaction with various energy-consuming post-conversion operations. The catalytic reactor is compartmentalized by means of a multilayer composite membrane comprising a catalytic membrane layer and one or more permselective membrane layers. The arrangement and properties of the membrane layers are such as to enable the free energy change of the conversion reaction to be utilized as the required energy source for effecting various post-conversion operations, including product separation, recovery and enrichment, and second-stage catalytic conversions with unfavorable reaction equilibria.

Abstract: .alpha.-Hydroxycarboxylic acids are continuously converted into the corresponding optically active .alpha.- aminocarboxylic acids. The conversion is carried out in a membrane reactor in the presence of nicotinamide-adenine dinucleotide increased in molecular weight by bonding to a water soluble high molecular weight material, a dehydrogenase specific for the .alpha.-hydroxycarboxylic acid, a dehydrogenase specific for the corresponding .alpha.-amino-carboxylic acid and ammonium ions. There is continuously supplied to the membrane reactor an aqueous solution of the .alpha.-hydroxycarboxylic acid to be reacted, a substantially lesser amount of the corresponding .alpha.-ketocarboxy lic acid, and an amount of ammonium ion at least equivalent to the .alpha.-hydroxycarboxylic acid to be reacted. There is maintained over the membrane a difference in pressure 1 and 15 bar. Behind the membrane, there is continuously drawn off a filtrate stream containing the .alpha.-aminocarboxylic acid formed.

Abstract: A method and apparatus for carrying out a degradation in an anaerobic medium, such as a methanogenesis, of organic products, by-products or waste from human, animal and/or plant origin, involving feeding said products to be degraded into a closed fermentation vessel, forcing said products to flow in a direction of circulation within said vessel and recovering the gas produced called biogas evolved above said body of degraded products, with the feeding and/or discharge of the products performed pneumatically, preferably through pneumatic thrust and, according to a preferred embodiment, by injection of gas, preferably biogas. A further improvement comprises using the biogas produced for homogenizing said body of products contained within said vessel, the pressure of injection being in relation to the actual density of the products, in the injection related section.

Abstract: The disclosure describes a method for producing lactic acid from carbohydrate-containing media by continuous fermentation utilizing particular methods of media pretreatment, cell-recycle fermentation, fermentation broth acidification, and lactic acid separation.

Abstract: An improved bioreactor and process for continuously propagating microorganisms, such as yeast, wherein the culture medium is purified in contact with a spirally-wound ultrafiltration membrane and then passed through the outer surfaces of a tubular membrane material for further purification before contact with microorganisms flowing in the interior of the tubular membrane material.

Abstract: A fermenter cell disposed so that the primary axis of the cell is approximately horizontal comprises solid partitions, arranged perpendicularly to the primary axis, which separate the cell into several chambers. The partitions are provided with apertures, each at a predetermined height, which allow liquid to pass; in addition, gas evacuation pipes are provided in the upper part of the chambers.

Abstract: Process for preparing Xanthomonas heteropolysaccharide from Xanthomonas campestris NCIB 11854 and use of the latter, e.g. as viscosity modifier in an aqueous solution, and in a drilling fluid and use in connection with well treatments, and enhanced oil recovery.

Abstract: In an enzymatic saccharification process, a sugar solution of constant sugar content is obtained by adding to the starch-containing raw materials, prior to the enzymatic saccharification step, part of the sugar solution obtained after the saccharification step and being separated from solid material and having been brought to a higher concentration, so that a higher sugar content, in particular within the range from 15 to 22% by weight and preferably approximately 20% by weight, can constantly be maintained, independent of the concentration and quality of the raw materials.

Abstract: It is possible by use of a sterilizable fluidized bed fermenter to carry out low-moisture fermentations. Fluidizable granulated microorganisms are used for this fermentation under sterile conditions in the fluidized bed fermenter which is initially operated as a bubble column.

Abstract: A cellulosic material is saccharified by cellulases and the resulting saccharified solution is acidified. Subsequently chitosan and/or partially deacetylated chitin are dissolved therein and the obtained solution is alkalified. Thus the cellulases are absorbed by the chitosan and/or partially deacetylated chitin. Further a cellulosic material is saccharified by at least one cellulase originating from a fungus belonging to the genus Aspergillus and at least either chitosan and/or partially deacetylated chitin are added to the resulting saccharified solution to thereby adsorb the cellulase by the chitosan and/or partially deacetylated chitin.

Abstract: Cellulose strands are produced by causing a growing medium containing Acetobacter xylinum to flow along a straight-line path over a growing surface. Cellulose fibrils produced by the bacteria arrange themselves in strands on the growing surface. These strands can be converted into threads and/or yarns. The cellulose fibrils produced by Acetobacter xylinum can also be converted to microcrystalline cellulose.

Abstract: The present invention is directed to the preparation of ethanol by bacterial fermentation. It makes use of a microorganism capable of producing ethanol and the process is carried out in two stages. In the first stage a bacterial cell suspension is produced together with ethanol in an ethanol concentration range that does not substantially inhibit production of the bacterial cells in a medium containing a source of nitrogen and a source of carbon. Ethanol is then produced in the absence of substantial bacterial cell production by the addition of fermentable sugar to the bacterial cell suspension which is produced in the first stage. The preferred microorganism is a member of the genus Zymomonas.

Abstract: A process for the saccharification of celluloses is provided. More particularly, a solution obtained after the degradative saccharification of cellulosic materials with cellulases is separated into a liquid portion containing saccharides and a solid matter. Cellulases are recovered from said liquid portion containing saccharides, while said solid matter is treated with an aqueous pH-buffered solution, or an aqueous solution, alcoholic aqueous solution or aqueous pH-buffered solution of polysaccharides or oligosaccharides, or aqueous or aqueous pH-buffered solution of alcohols to recover the cellulases in the solid matter. With the use of this solid matter, newly added cellulosic materials are degradatively saccharified in an aqueous solution or the above-mentioned solutions.

Abstract: The invention provides a method for producing lactic acid by continuous fermentation utilizing particular methods of media pretreatment, cell-recycle fermentation, fermentation broth acidification, and lactic acid separation.

Abstract: Polysaccharides are produced by single stage continuous culture of Xanthomonas bacteria, especially of the Xanthomonas campestris group in a chemically-defined culture medium. Cultures have been run for over 2,000 hours without reduction in the polysaccharide yield. The physical and chemical properties of the product can be controlled by selection of the growth limiting substrate (limiting nutrilite) in the culture medium to give a range of polysaccharides suitable for various applications.

Abstract: Polysaccharides, such as xanthan gum, are produced by culturing microorganisms, e.g. of the Xanthomonas genus, in a two stage process. In the first stage, growth of the microorganism is favored, e.g. by using a predetermined quantity of a carbon-containing nutrient which does not support biosynthesis of the polysaccharide. In the second stage, the conditions are such that biosynthesis of the polysaccharide takes place with substantially no growth of the microorganism, e.g. by adding carbohydrate in the absence of nutrient required for polysaccharide growth.By this process, the requirement for oxygen is greatly reduced at the time when the culture medium has its highest viscosity, thereby minimizing problems of low oxygen transfer capability in viscous media.

Abstract: The invention relates to a transparent polyurethane foam wall optionally containing microorganisms, and a process for the preparation thereof, and the use of this wall in a biophotoreactor. This wall has pores, in which are distributed microorganisms and the pores are closed on one of the faces of the wall, in such a way that said face is impermeable to liquids and gases, while the other face of the wall has an open porosity. Thus, by circulating a liquid nutrient medium and a gas along the second face of the wall and exposing the first face thereof to light, it is possible to culture microorganisms and collect the metabolites formed by them in the liquid medium.

Abstract: A method for production of HA fraction containing protective antigens of Bordetella pertussis (i.e. a fraction containing F-HA and LPF-HA) in an industrial scale, for instance, with a fermentater, which comprises inoculating a strain of B. pertussis in a liquid culture containing a cyclodextrin or its derivative, culturing it by a spinner culture under controlling the culture temperature and the amount of dissolved oxygen and under defoaming condition, optionally under controlling the pH range, and harvesting the produced HA fraction from the culture broth at a stage of from logarithmic growth phase to static grow phase, and a method for production of a pertussis vaccine from the HA fraction thus obtained by formalinizing the HA fraction in the presence of an amino acid.

Abstract: A feed liquid (sugar-containing liquid) is continuously fed to a fermenter packed with an immobilized microorganism, which is obtained by immobilizing an alcohol producing microorganism on a carrier, for alcohol fermentation. The fermentation liquid is continuously taken out of said fermenter and is heated to a temperature of 35.degree. to 80.degree. C. This liquid is introduced into a flash tank maintained at reduced pressure and is divided into an alcohol-containing steam and a liquid. The alcohol-containing steam is condensed and recovered as alcohol, while the separated liquid is cooled and is cycled back to said fermenter.

Abstract: A novel immobilized cell reactor design is described capable of separating an inhibitory metabolite from a fermentation broth as it is formed. This reactor has the dual advantages of (1) speeding product inhibited reactions and (2) giving a concentrated product free of substrate and cells. The immobilized cell reactor separator (ICRS) can consist of two columns; in the first or `enriching` column stripping gas and broth move co-currently after which the liquid phase moves to the top of the second `stripping` column and moves counter currently to the stripping gas while the remaining substrate is converted to product. The use of this reactor in an ethanol from whey lactose fermentation system is also described.

Abstract: Ethanol is produced from D-xylose by fermentation with any of the known xylose-metabolizing yeasts, such as Pachysolen tannophilus. To improve the yield of ethanol, small quantities of glucose are added to the fermentation medium during the fermentation process.

Abstract: The present invention is directed to the preparation of ethanol by bacterial fermentation. It makes use of a microorganism capable of producing ethanol and the process is carried out in two stages. In the first stage a bacterial cell suspension is produced together with ethanol in an ethanol concentration range that does not substantially inhibit production of the bacterial cells in a medium containing a source of nitrogen and a source of carbon. Ethanol is then produced in the absence of substantial bacterial cell production by the addition of fermentable sugar to the bacterial cell suspension which is produced in the first stage. The preferred microorganism is a member of the genus Zymomonas.

Abstract: A bioreactor arrangement comprises a housing defining a closed space having a longitudinal axis with at least two spaced apart microporous membranes fixed therein dividing the space into a first chamber on one side of one of the membrane, a second chamber on one side of the other membrane, and a third chamber between opposite sides of the one and other membrane. The housing includes at least one port communicating with each chamber and fixed static mixers in the form of curved and/or perforated members in the third chamber. The first and second chambers are used alternately to receive and discharge material in the bioreactor. The third chamber contains an active substance which produces a useful product from raw materials in the supplied fluid. A flow valve and pump are provided for selectively supplying fluid carrying raw material to one or the other of the first and second chambers.

Abstract: A column reactor, suitable for continuous production of a gaseous reaction product by contacting a liquid reaction medium with a gas-forming agent fixed to a reaction plug comprising a solid substrate provided with a plurality of gas-forming channels. The column reactor overcomes the apparent short circuiting of liquid reaction medium through the reactor by being provided with two or more reaction zones, each zone having its own circulatory by-pass means for liquid reaction medium. To obtain the reaction zones a reaction plug can be divided into two or more spaced apart plug portions. For each reaction zone the circulatory by-pass means provides a portion of the pathway for an internal recirculation current of liquid reaction medium.

Abstract: A process for obtaining glucose from thinned starch by partially hydrolyzing the latter to give from 50% to 92% glucose followed by separation of the hydrolysis product to afford a glucose-enriched product with recycling of the glucose-depleted stream affords benefits unattainable by conventional commercial processes. Substantial reductions in process time and reversion products and a substantial increase in productivity are among some of the benefits.

Abstract: In a fermentation procedure for the production of nucleosides i.e. inosine and/or guanosine using an adenine-requiring microorganism, the fermentation is carried out by allowing a source of adenine to be present in the medium in an excess amount over the amount of adenine that would be conductive to a maximum yield of inosine and/or guanosine in aerobic culture using ordinary air, and cultivating the microorganism while an oxygen-rich gas is bubbled into the medium. Thus, inosine and/or guanosine are accumulated in high yield in the fermentation broth.

Abstract: There is disclosed, in one aspect, a continuous process for producing n-butanol. This process comprises continuously (a) contacting at least one carbohydrate-containing substrate, such as blackstrap molasses, with an n-butanol producing culture, such as Clostridium acetobutylicum (Weizmann), in water to effect the fermentation of the substrate and form a product mixture comprising n-butanol, (b) extracting the product mixture from the substrate, culture, and water by forming a solution of the product mixture with an extraction solvent, such as a one or two carbon fluorocarbon, (c) separating the extraction solvent from the product mixture by vaporizing substantially all of the solvent without substantial vaporization of the product mixture, and (d) condensing the vaporized solvent for reuse as an extraction solvent in step (b). In another aspect, there is disclosed an apparatus for conducting such a process.

Abstract: A continuous alcohol manufacturing process using yeast comprising a zone where a conventional yeast (Yeast B) which has an alcohol producing activity is mainly present (zone of Yeast B); a zone disposed in the fore part of said zone of Yeast B where a yeast (Yeast A) which has an alcohol producing activity and is superior in sugar resistance as compared with Yeast B is mainly present (zone of Yeast A); and a zone disposed in the rear part of said zone of Yeast B where a yeast (Yeast C) which has an alcohol has an alcohol producing activity and is superior in alcohol resistance as compared with Yeast B is mainly present (zone of Yeast C), wherein a substrate solution is supplied to said zone of Yeast A thereby to effect alcohol fermentation; the resulting fermentation liquid is introduced in said zone of Yeast B thereby to effect alcohol fermentation; the resulting fermentation liquid is further introduced in said zone of Yeast C thereby to effect alcohol fermentation; and then a product alcohol broth is obtai

Abstract: A method is described for the manufacture of commercially useful alpha-halo and alpha-dihalo ketones and aldehydes from alkynes by enzymatic reaction. The alkyne is acted upon in a reaction mixture comprising a halogenating enzyme, an oxidizing agent, and a halide ion source.

Abstract: This invention provides an improved fermentation process for bioconversion of toluene to muconic acid.The process involves operating the bioconversion system under phosphate-limiting conditions so as to achieve an increase in specific muconic acid productivity with a stabilized population of microorganism such as an ATCC No. 31,916 type of Pseudomonas putida Biotype A mutant strain.

Abstract: Alcohol substantially free of water is prepared by continuously fermenting a fermentable biomass feedstock in a fermentation unit, thereby forming an aqueous fermentation liquor containing alcohol and microorganisms. Continuously extracting a portion of alcohol from said fermentation liquor with an organic solvent system containing an extractant for said alcohol, thereby forming an alcohol-organic solvent extract phase and an aqueous raffinate. Said alcohol is separated from said alcohol-organic solvent phase. A raffinate comprising microorganisms and unextracted alcohol is returned to the fermentation unit.

Abstract: A reactor for the anaerobic digestion of organic sludge and for the production of methane gas, comprises an essentially horizontal cylindrical vessel provided with an agitator rotating around an essentially horizontal shaft, an inlet for introducing the sludge to be digested at one end of said vessel, at its opposite end an outlet for removing the digested matter from the vessel and in the upper portion of the vessel an outlet/outlets for the recovery of methane gas. For returning the solids settled on the bottom of the vessel from the outlet end of the vessel to the inlet end of the vessel, the vessel comprises a channel connecting the outlet end of the vessel with the inlet end of the vessel and a device for guiding the solids to the front of the return channel and for their transport through the return channel by means of gas.