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: 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: The present invention is directed to a two-stage continuous process for the production of a gelable curdlan-type exopolysaccharide. In the first stage a stable, curdlan-producing strain of microorganism such as Alcaligenes faecalis var. myxogenes ATCC 31749 and ATCC 31750, is grown aerobically in an aerated, agitated culture medium containing assimilable carbon, nutrients and organic salts. The amount of nitrogen in the first stage is so limited that the effluent therefrom contains substantially no inorganic nitrogen. The effluent is introduced into a second stage in a constant volume fermenter wherein it is mixed with a nitrogen-free carbohydrate. The resultant mixture is aerated and mixed at pH 5.5 to 6.5 at a temperature of from 25.degree. to 35.degree. C.

Abstract: The present invention relates to a process for the isolation of protein from microbial cells. The microbial cells are subjected to a treatment to disrupt the cell walls thereby producing a cellular debris fraction and a fraction containing protein and nucleic acid. The two fractions are separated and the fraction containing the protein and nucleic acid is treated with a chelating agent at a pH in the range of 5.5 to 7.0. The resulting solution is passed through an anion exchange column which selectively adsorbs the nucleic acid. The protein is recovered from the resultant eluate.