Cross-linked aggregates of penicillin acylase: robust catalysts for the synthesis of beta-lactam antibiotics

A novel method for the immobilization of penicillin G acylase (penicillin a midohydrolase, E.C. 3.5.1.11) is reported. It involves the physical aggrega tion of the enzyme, followed by chemical cross-linking to form insoluble cr oss-linked enzyme aggregates (CLEAs). Compared with conventionally immobili zed penicillin G acylases, these CLEAs possess a high specific activity as well as a high productivity and synthesis/hydrolysis (S/H) ratio in the syn thesis of semi-synthetic antibiotics in aqueous media. Moreover, they are a ctive in a broad range of polar and apolar organic solvents. (C) 2001 Elsev ier Science B.V. All rights reserved.