Improvement of docosahexaenoic acid production on glycerol by Schizochytrium sp. S31 with constantly high oxygen transfer coefficient

Abstract

Volumetric mass transfer coefficient (kLa) is a key fermentation parameter for the production of docosahexaenoic acid (DHA) from glycerol by Schizochytrium sp. S31. In order to elucidate the effects of kLa on the fermentations, both baffled and unbaffled flask cultures and fed-batch cultures were developed in present work. The results showed that high kLa could effectively increase the DHA concentration, DHA productivity and conversion yield (Yx/s, g/g). When kLa was set at 1802 ± 105 h(-1) in the fed-batch culture, DHA concentration was achieved at 28.93 g/L, DHA productivity at 301 mg/L/h and Yx/s at 0.44 ± 0.02 g/g, all of which were significantly higher than those in the previous similar studies.

Keywords: DHA; Glycerol; Oxygen; Schizochytrium sp.; k(L)a.