Cross-linked enzyme aggregates: A simple and effective method for the immobilization of penicillin acylase

Penicillin G acylase (penicillin amidohydrolase, E.C. 3.5.1.11) was immobilized in a simple and effective way by physical aggregation of the enzyme, using a precipitant, followed by chemical cross linking to form insoluble cross-linked enzyme aggregates (CLEAs), These had the same activity in the synthesis of ampicillin as cross-linked crystals of the same enzyme, but the accompanying hydrolysis of the side-chain donor was much less. Penicillin G acylase CLEAs also catalyzed the synthesis of ampicillin in a broad range of organic solvents.