Immobilization of Lipase on Zwitterionic Polymer-Modified Magnetic Chitosan Microspheres for Enhancing Enzyme Performance

Abstract

In this work, the novel zwitterionic polymer-modified magnetic chitosan microspheres (PMCTS) were fabricated by a simple one-pot synthesis for covalent immobilization of Candida rugosa lipase (CRL). The zwitterionic polymer used was a derivative of poly(isobutylene-alt-maleic anhydride) and N,N-dimethylethylenediamine, with some residual anhydrides. The immobilization conditions and the characterization of immobilized lipase were evaluated systematically. The resulting immobilized lipases (PMCTS-CRL) exhibited higher relative activity than CRL on the unmodified chitosan magnetic microspheres (MCTS-CRL), comparable to the activity of free counterpart under optimal conditions. Moreover, PMCTS-CRL showed enhanced thermal, pH and storage stabilities in comparison with free CRL and MCTS-CRL, and better reusability than MCTS-CRL. PMCTS-CRL exhibited a 21.3-fold and 5.49-fold higher half-life than free one and MCTS-CRL at 50 ℃. These results demonstrated that zwitterionic polymer-modified chitosan magnetic microsphere is a potential support for enzyme immobilization.