CFD investigation of <Emphasis Type="Italic">Schizochytrium</Emphasis> sp. impeller configurations on cell growth and docosahexaenoic acid synthesis

Effects of impeller configurations on docosahexaenoic acid production and flow characteristics were investigated by Schizochytrium sp. in a 15 L bioreactor. 6-straight blade disc turbine (6-SBDT), 6-arrowy-blade disc turbine (6-ABDT) and down-pumping propeller (DPP) were combined to form different impeller configurations. Simulated results showed that configuration SSA consisting of upper two 6-SBDT and one bottom 6-ABDT possessed the worst oxygen supply capacity. But it obtained the highest DHA percentage of 48.17 % and DHA yield of 21.42 g/L, indicating that it was beneficial for DHA synthesis and converting glucose to biomass and lipids. Configuration SAS consisting of one middle 6-ABDT and two 6-SBDT provided better mixing capacity, which resulted in the maximum glucose consumption rate of 2.86 g/L h and the highest biomass of 108.09 g/L. This study would improve insight into understanding the relationship between flow field and the physiology of Schizochytrium sp. for the scale-up of industrial DHA production.