Fed-batch cultivation of Acetobacter suboxydans for the microbial oxidation of D-sorbitol to L-sorbose

Microbial oxidation of D-sorbitol to L-sorbose is commercially important since it is the only biochemical process in Vitamin-C manufacture. The main bottleneck in the batch oxidation of D-sorbitol is that the process is severely inhibited by sorbitol. By conducting fed-batch fermentation, the inherent substrate inhibition present in batch fermentation can be eliminated. Batch fermentation with an initial sorbitol concentration of 200 g l(-1) featured a productivity of 14.2 g l(-1) h(-1) and a final sorbose concentration of 200 g l(-1). Fed-batch fermentation conducted by feeding nutrients containing 600 g l(-1) of sorbitol at a constant feed rate of 0.36 1 h(-1) yielded a productivity of 17.7 g l(-1) h(-1) and a final sorbose concentration of 320 g l(-1).