CONTINUOUS PRODUCTION OF L-ASPARTIC ACID FROM AMMONIUM FUMARATE USINGIMMOBILIZED CELLS BY CAPTURE ON THE SURFACE OF NONWOVEN CLOTH COATED WITH A PYRIDINIUM-TYPE POLYMER

Cells of Escherichia coli possessing aspartase activity were immobiliz ed by capture on the surface of nonwoven cloth coated with 10 mg/g of poly (N-benzyl-4-vinylpyridinium chloride-co-styrene), a pyridinium-ty pe polymer. Continuous operation of a fixed-bed column reactor contain ing 21.7 g/l of the immobilized cells produced L-aspartic acid in 95% yield from ammonium fumarate in the case where influent solution conta ined 0.1 mol/l of the fumarate and space velocity was 1.36 h(-1) at 30 degrees C and pH 8.9. Immobilization on the coated nonwoven cloth ins ignificantly affected optimal pH of the biochemical reaction. Stabilit y of enzymic activity of the immobilized cells was much improved by us e of the coated nonwoven cloth as the supporting material instead of b eads of insoluble pyridinium-type resin. L-Aspartic acid was obtained in 77% yield after 160 d of continuous operation, and the initial yiel d was estimated to require about 500 d for halving.