Study on the optimum condition for immobilization and properties of laccase on coordinated chitosan-Cu~(2+)

摘要

Coordinated chitosan-Cu~(2+) as a carrier, the laccase was immobilized on it by polymeric coordination method. In this study, the optimal conditions for immobilization and properties of laccase were investigated. The optimal conditions for immobilization were: CuSO_4 (0.05 mol/L), complex time (7 h), laccase concentration (250 U/mL), immobilization time (8 h). Under this condition, the activity of immobilized laccase can reach 820 U/g. In comparison with the free laccase, the optimum pH and temperature of immobilized laccase have a little change, while the heat resistance and pH stability were improved. After the immobilized laccase was stored in the refrigerator at 4 °C for 25 days, the activity of it remained 69.5 % of the original, it illustrates the immobilized laccase has a good storage stability. The laccase immobilized with chitosan-Cu~(2+) has high activity and has potential to use in industry as a biocatalyst.