FERMENTATION PERFORMANCE OF ZYMOMONAS-MOBILIS AGAINST OXYGEN-SUPPLY .1. FERMENTATIVE ABILITY OF ZYMOMONAS-MOBILIS UNDER VARIOUS OXYGEN-SUPPLY CONDITIONS IN BATCH CULTURE

The performance of Zymomonas mobilis under various oxygen supply conditions in batch culture was quantitatively investigated. Although both the cell growth rate and ethanol productivity decreased with increases in the oxygen supply, the production of by-products such as acetaldehyde and acetic acid increased. The ethanol productivity was more sensitive to oxygen supply than the growth rate. Oxygen supply also affected the morphology of the cells and an increase in oxygen supply resulted in the elongation of the cells. It was also found that both metabolic activity and fermentation balance were largely affected by changes in the dissolved oxygen concentration during the steady state in oxygen concentration. © 1990.