Synthesis Of Magnetic Polymer Microspheres With Epoxy Groups For Immobilization Of Penicillin G Acylase

The magnetic polymer microspheres with epoxy groups was successfully synthesized by inverse suspension polymerization and characterized by FT-IR, XRD, SEM, BET, VSM. Fe3O4nanopaticles with superparamagnetism were synthesized by the co-precipitation method, in which the preparation procedure was optimized. The average diameter and the saturation magnetization was about13nm and78emu/g, respectively.Sodium oleic and sodium dodecyl sulfate acted as bilayer surfactants to modify Fe3O4nanoparticles to improve their hydrophilicity. Magnetic polymer microspheres with epoxy groups were prepared by inverse suspension polymerization in the presence of magnetic nanoparticles coated with bilayer surfactants. Penicillin G acylase (PGA) was covalently immobilized on the magnetic polymer microspheres, in which the initial activity of immobilized PGA was250U/g (wet) and it retained94%of its initial activity after recycled for10times.SiO2was used to modify Fe3O4nanoparticles to improve their compatibility with monomers. Magnetic polymer microspheres with super-paramagnetic, good spherical shape and uniform particle size were prepared by inverse suspension polymerization in the presence of Fe3O4SiO2. PGA was covalently immobilized on the magnetic polymer microspheres. The immobilized condition was optimized, in which the initial activity of immobilized PGA was430U/g (wet), and it retained99%of its initial activity after recycled for10times. The immobilized PGA has good thermostability below55℃and good pH stability when the pH values was ranging from4tol1.