Preparation of immobilized glucose oxidase on magnetic composite particles

Magnetic Fe3O4was synthesized by chemical coprecipitation. PDDA with positive charge was adsorbed on the surface of Fe3O4,forming PDDA-Fe3O4composites. In order to improve the stability and repeating utilization factor of glucose oxidase,glucose oxidase was immobilized on the self-made magnetic PDDA-Fe3O4carrier via electrostatic interaction. The results showed that the average size and Zeta potential of PDDA-Fe3O4particle were 275 nm and 47. 6 mV,respectively. The optimal immobilization conditions were as follows: temperature 15 ℃,pH = 6,and the mass ratio of enzyme and carrier of 1∶ 66. The thermal stability,pH stability and operational stability of the immobilized enzyme were all improved greatly.