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Title: Effect of air supplement on the performance of contiuous ethanol fermentation system. [Saccharomyces cerevisiae]

Journal Article · · Biotechnol. Bioeng.; (United States)

For the purpose of improving ethanol productivity, the effect of air supplement on the performance of continuous ethanol fermentation system was studied. The effect of oxygen supplement on yeast concentration, cell yield, cell viability, extracellular ethanol concentration, ethanol yield, maintenance coefficient, specific rates of glucose assimilation, ethanol production, and ethanol productivity have been evaluated, using a high alcohol tolerant Saccharomyces cerevisiae STV89 strain and employing a continous fermentor equipped with an accurate air metering system in the flow rate range 0-11 mL air/L/h. It was found that, when a small amount of oxygen up to about 80..mu.. mol oxygen/L/h was supplied, the ethanol productivity was significantly enhanced as compared to the productivity of the culture without any air supplement. It was also found that the oxygen supplement improved cell viability considerably as well as the ethanol tolerance level of yeast. As the air supply rate was increased, from 0 to 11 mL air/L/h while maintaining a constant dilution rate at about 0.06 h/sup -1/, the cell concentration increased from 2.3 to 8.2 g/L and the ethanol/L/h, although the specific ethanol production rate decreases slightly from 0.75 to 0.5 g ethanol/g cell/h. The ethanol yield was slightly improved also with an increase in air supply rate, from about 0.37 to 0.45 ethanol/g glucose. The maintenance coefficient increased by only a small amount with the air supplement. This kind of air supplement technique may very well prove to be of practical importance to a development of a highly productive ethanol fermentation process system especially as a combined system with a high density cell culture technique.

Research Organization:
Univ. of California, Davis
OSTI ID:
6859689
Journal Information:
Biotechnol. Bioeng.; (United States), Vol. 26:1
Country of Publication:
United States
Language:
English