Synthesis of Core/Shell Magnetic Porous Microspheres for Lipase Immobilization

Abstract

Magnetic porous hydrophobic microspheres were prepared by modified suspension copolymerization of methacrylate (MMA) and divinylbenzene (DVB) in the presence of oleic acid coated magnetite (Fe3O4), and the microspheres were used as biocarrier for the lipase immobilization. The results showed that the magnetic microspheres possessed spherical shape, core/shell structure, porous structure and high magnetic content, and the size and structure of magnetic microspheres had no significant changes after enzyme binding. The particle average size of microspheres was 66 μm, the magnetic content of microspheres was up to 31%, and the magnetization saturation values of the core/shell magnetic microspheres were measured at 300 K to be 11.02 emu g−1. Lipase was immobilized on the magnetic porous carrier at up to 16.30 mg/g carrier. Activity and enantioselectivity of the immobilized lipase for the synthesis of R-HMPC acetate were investigated, indicating an interfacial activation of the enzyme after immobilization. Moreover, the pH dependency and operational stability of the immobilized lipase were studied, and they possess high stability and can be reused for ten cycles with loss 10% activity.