Scale-up of docosahexaenoic acid production in fed-batch fermentation by Schizochytrium sp. based on volumetric oxygen-transfer coefficient

Abstract

The scale-up of fed-batch fermentation process for the DHA (docosahexaenoic acid)-rich microbial lipids production by Schizochytrium sp. from shake flasks to bench-scale (10l and 50l) and pilot-scale (1500l and 7000l) stirred fermentors was studied. The fermentation process was successfully scaled-up from experimental-scale to bench-scale and pilot-scale at matched KLa value (88.9h−1) estimated by the KLa model developed in this study and the KLa empirical equations. The fermentation performances of the bench-scale and pilot-scale (DHA content of 13.96, 14.44 and 14.16gl−1 in the 10l, 50l and 1500l fermentor) processes were similar to that of the experimental-scale process (DHA content of 13.84gl−1) and the fermentation results obtained in the 7000l stirred fermentors (DHA content of 19.72gl−1) were much higher. These results indicated that KLa was applicable for the scale-up of the fed-batch fermentation process of DHA production by Schizochytrium sp. and this scale-up strategy enabled a maximum of 150-fold quantitative scale-up of the fed-batch fermentation process.