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

Abstract Volumetric mass transfer coefficient (k L a) 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 k L a on the fermentations, both baffled and unbaffled flask cultures and fed-batch cultures were developed in present work. The results showed that high k L a could effectively increase the DHA concentration, DHA productivity and conversion yield (Y x/s, g/g). When k L a 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 Y x/s at 0.44 ± 0.02 g/g, all of which were significantly higher than those in the previous similar studies.