Immobilization of penicillin G acylase on paramagnetic polymer microspheres with epoxy groups

Abstract Paramagnetic polymer microspheres were synthesized by the inverse suspension polymerization method through polymerization of glycidyl methacrylate, ally glycidyl ether and methacrylamide on the surface of silica-coated Fe 3 O 4 nanoparticles using N , N ’-methylene-bis(acrylamide) as a cross-linking agent. Penicillin G acylase (PGA) was covalently immobilized on the surface of the paramagnetic microspheres by reacting the amino groups of the PGA molecules with the epoxy groups of the paramagnetic polymer microspheres. The effect of the SiO 2 coating and the amount of paramagnetic Fe 3 O 4 nanoparticles on the initial activity and the operational stability of the immobilized PGA was investigated. The results indicated that SiO 2 played an important role in the polymerization process and paramagnetic polymer microspheres with a SiO 2 -coated Fe 3 O 4 nanoparticles mass content of 7.5% are an optimal support material for PGA immobilization. Immobilized PGA on the paramagnetic polymer microspheres shows a high initial activity of 430 U/g (wet) and retains 99% of its initial activity after recycling 10 times. Furthermore, immobilized PGA exhibits high thermal stability, pH stability and excellent reusability, which can be rapidly recycled by the aid of magnet.