To enhance the penicillin acylase covalent immobilization efficiency, microwave irradiation was introduced to the enzyme immobilization process. Mesocellular siliceous foams (mesostructured cellular foams, MCFs) with large pores were synthesized by hydrolytic condensation of tetraethoxysilicone, and penicillin acylase was rapidly coupled to MCFs with covalent linkages by benzoquinine under microwave irradiation. The relative activity and the activity recovery of immobilized enzyme were taken as indexes, and the effects of immobilization conditions such as the reaction time, temperature and amount of penicillin acylase were investigated. When the amount of penicillin acylase, temperature and reaction time for immobilization was 60 mg/g MCFs, 20 ℃ and 140 s respectively, the activity of the wet immobilized enzyme was 1191.3 U/g, and the relative activity was up to 178.1%. Compared with those of conventional methods, the relative activity has increased by 34.5%, and the immobilization under microwave irradiation could shorten the reaction process to a few minutes, which provided a new way for immobilizing penicillin acylase.

Key words: microwave irradiation, penicillin acylase, mesocellular siliceous foam, immobilized enzyme