Enhanced product formation in continuous fermentations with microbial cell recycle*

The effect of partial recycle of microbial cells on the operation of a chemostat has been investigated for two fermentations. Stable steady states without partial cell recycle were obtained for the conversion of D -sorbitol to L -sorbose by Gluconobacter oxydans subsp. suboxydans 1916B and for the conversion of glucose to 2-ketogluconic acid by Serratia marcescens NRRL B-486. The employment of partial cell recycle dramatically increased product formation rates for both fermentations.