Immobilization of Escherichia coli cells with cis-epoxysuccinate hydrolase activity for D(-)-tartaric acid production.

Immobilization of cis-epoxysuccinate hydrolase-containing E. coli for D(-)-tartaric acid production was screened by various methods. The highest recovery of activity was obtained by entrapment in kappa-carrageenan gel. 23.6 g biomass/l and 43.4 g kappa-carrageenan/l were the best immobilization conditions optimized by response surface methodology with 83% yield (114 U/g). Cell autolysis was observed after immobilization. Immobilized cells showed high pH (5-10) stability, thermal (up to 65 degrees C) stability, conversion rate (>99.5%), enantioselectivity (ee > 99.6%), and were less affected by metal ions and surfactants compared with free cells. Conversion rate for immobilized cells preserved 93% after 10 repeated batches (5% for free cells).