IMMOBILIZATION OF AMINOACYLASE IN POLYETHYLENEIMINE STABILIZED CALCIUM ALGINATE BEADS FOR L-PHENYLALANINE PRODUCTION

Aminoacylase I ( E.C.3.5.1.14) was immobilized by entrapment in calciu m alginate beads coated with polyetheleneimine for the production of L -phenylalanine by the hydrolysis of a racemic mixture of N-acetyl-DL-p henylalanine. The operational stability in terms of batch operation an d continuous reaction in packed-bed bioreactor were studied. Kinetic c onstants, K(m) and V(max) values of free and immobilized enzymes were studied. Polyethyleneimine treatment was found to enhance the operatio nal stability of the enzyme though its activity was substantially redu ced. When polyethyleneimine-coated calcium alginate beads were packed into packed bed bioreactor, it was stable for at least 25 days under c ontinuous operation without appreciable loss of activity.