title: Novel magnetic microspheres of P (GMA-b-HEMA): preparation, lipase immobilization and enzymatic activity in two phases.
abstract: Magnetic oleic-acid-coated Fe₃O₄ nanoparticles were first introduced into 1, 1-diphenylethylene (DPE)-controlled radical polymerization system to prepare superparamagnetic microspheres for enzyme immobilization by two steps of polymerization. In the presence of DPE, glycidyl methacrylate, 2-hydroxyethyl methacrylate and methacryloxyethyl trimethyl ammonium chloride with charge were selected as copolymering monomers based on their reactive functional group and excellent biocompatibility which were suitable for immobilization of Candida rugosa lipase (CRL). The resulting magnetic microspheres were characterized by means of scanning electron microscope, Fourier transform infrared spectrum, thermogravimetric analysis and vibrating sample magnetometry. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis SDS-PAGE analysis was also conducted to demonstrate whether CRL is covalently immobilized or only physically adsorbed. The results indicated that the polymerization was successfully carried out, and lipase was immobilized on the magnetic microspheres through ionic adsorption and covalent binding under mild conditions. The immobilized lipase exhibited high activity recovery (69.7%), better resistance to pH and temperature inactivation in aqueous phase, as well as superior reusability in nonaqueous phase. The data showed that the resulting carrier could hold an amphiphilic property.
authors.affiliation: College of Chemistry and Chemical Engineering, State Key Laboratory of Applied Organic Chemistry, Institute of Biochemical Engineering & Environmental Technology, Lanzhou University, Lanzhou 730000, China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Cui
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Li
authors.forename: Xiao
authors.initials: X
authors.lastname: Liu
authors.forename: Lin
authors.initials: L
authors.lastname: Lei
authors.forename: Sunting
authors.initials: S
authors.lastname: Xuan
mesh_terms: D001709:Biotechnology; D002175:Candida / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D004852:Epoxy Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D008280:Magnetics; D008689:Methacrylates / Q000737:chemistry*; D008863:Microspheres; D011108:Polymers / Q000737:chemistry*; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D004852:Epoxy Compounds; D008689:Methacrylates; D011108:Polymers; C005044:hydroxyethyl methacrylate; D008049:Lipase; C007870:glycidyl methacrylate