The effect of volumetric oxygen transfer coefficient (kLa)

on the performance of producing pyruvate by a multi - vitamin - auxotrophic yeast of Torulopsis glabrata

was investigated in batch fermentation process. High yield of pyruvate to glucose (0.797 g·g-1) was achieved at higher kLa (450 h-1)

while the glucose consumption rate was low (1.14 g·L-1·h-1). Glucose consumption was enhanced at lower kLa (200 h-1)

however

the yield of pyruvate to glucose decreased to 0.483 g·g-1. Based on the characteristics of process parameters and carbon flux distribution

a two - stage oxygen supply control mode

in which kLa was controlled at 450 h in the first 16 h then switched to 200 h after 16 h

was proposed and experimentally verified. Relative high concentration of pyruvate (69.4 g·L-1)

high yield of pyruvate to glucose (0.636 g· g-1)

and high glucose consumption rate (1.95 g·L-1·h-1) was achieved by applying this mode. The productivity (1.24g·L-1·h-1) was improved by 36%

23% and 31% than the cases of constant KLa (450 h-1

300 h-1 and 200 h-1)

respectively. Experimental results indicate that the difference between the performance of producing pyruvate under favorable state of oxygen- supply was caused by the different energy state of cell

which may be due to the different regenerated pathways of NADH generated from glycolysis.