Effect of pH and ventilatory capacity control strategies on biomass and 6G-fructofuranosidase activity of Xanthophyllomyces dendrorhous in the fermentor

The effect of initial culture pH and controlled pH ranging from 7. 0 to 9. 0 and VC (ventilatory capacity) ranging from 5 to 12L/min on biomass and 6G-fructofuranosidase activity by Xanthophyllomyces dendrorhous which were using in the free-whole-cell biotransformation were investigated in batch fermentation. An optimal pH of 7. 0 and VC of 5L/min were obtained for cell growth, cell density was 11. 6g/L and 11. 8g/L, respectively, and an optimal pH of 8. 0 and VC of 8L/min were obtained for 6G-fructofuranosidase activity, both of them were 0. 32mol/L/min. Comprehensive consideration of the cell density and 6G-fructofuranosidase activity, the final optimal pH and VC for fermentation was 8. 0 and 8L/min, respectively.