Preparation Of Polymer GMA-IDA-grafed Magnetic Microsphere And Its Immobilization Of Tyrosinase

Immobilized tyrosinase are widely used in synthesis of L–Dopa, industrial wastewater treatment, electrochemical analysis of phenolic pollutants and food industries,and various of novel magnetic immobilization of tyrosinase is exploring by many researchers. In this paper, a novel submicron-sized magnetic microspheres(PM) grafted by Polymer GMA-IDA were prepared, and were applied in immobilization of tyrosinase. The detail syntheses and characterization of PM and its applications were investigated as follows:1. PM were obtained by solvent polymerization, in which GMA-IDA monomers were grafted directly on magnetic particles(MNP) which were prepared via solvothermal. The structures and properties of PM and MNP were characterized by IR, TG, SEM, and VSM. The results indicated PM were of sphere, and with saturation magnetization of 56.8 emu/g , polymer-grafted ratio of 38.5%. When copper(Ⅱ) ion in 50 mg/mL CuSO₄ was absroped by PM, PM-Cu with an adsorption capacity of 130 mg/ml were obtained.2. Tyrosinases were immobilized on PM-Cu by affinity adsorption, and the properties of two kinds of immobilization of tyrosinase were investigated, named PM-Cu-E(pH 4) and PM-Cu-E(pH 6), respectively. The immobilized tyrosinase showed the maximum adsorption capacity of 123.5 mg/g at pH 4.0. buffer solution. PM-Cu-E(pH 6) were found to have grater activity at broad acid and base than the soluble enzyme and PM-Cu-E(pH 4). Immobilization stabilized the enzyme, and PM-Cu-E (pH 6) retained 90% of its initial activity after storing at 4℃, pH 6.0 buffer solution for 150 days, while PM-Cu-E(pH 4) remained 95 % after storing at 4℃, pH 4.0 buffer solution for 20 days, and then the activity decreased rapidly. In addition, after 5 successive adsorption-desorption cycles, the adsorption capacity and activity recovery of regenerated magnetic beads had no remarkable change.