New method of immobilization of microbial cells by capture on the surface of insoluble pyridinium‐type resin

A new method for the immobilization of microbial cells has been developed. Whole cells of Escherichia coli with aspartase activity were immobilized by capture on the surface of cross‐linked poly( N ‐benzyl‐4‐vinylpyridinium bromide) containing styrene (BVPS resin), an insoluble pyridinium‐type resin. When a suspension of the bacterial cells in buffer solution was passed through a glass column containing beads of BVPS resin, the cells were captured on the resin surface and formed an immobilized cell system. A fixed‐bed column reactor containing 300 mg of the bacterial cells immobilized by capture on 10 g of BVPS resin beads was used for the preparation of L ‐aspartic acid from ammonium fumarate. Continuous operation of tne bioreactor produced L ‐aspartic acid in a quantitative yield when the influent substrate concentration was 0.1 M and the flow rate was 0.41–0.83 bed volumes per hour at pH 7.4–7.7 at 30°C.