Study of Immobilization of Laccase on Mesoporous Molecular Sieve MCM-41

The mesoporous molecular sieve MCM-41 was employed as the support for the immobilization of enzyme laccase, and the laccase was loaded into the MCM-41 by the physical adsorption method. The effects of immobilization time, pH value and the amount of enzyme provided on the immobilization were investigated, and the activity and stability of the immobilized enzyme were also studied. The main factors that influence the immobilization process and properties of the immobilized enzyme were discussed. Under pH=3, the optimum conditions for immobilization of laccase were found as follows: the immobilization time of 12 h and the ratio of enzyme to MCM-41 of 62.5 mg·L–1, and using them, the activity recovery of the immobilized laccase is 50 %. Comparing with the free laccase, the optimum working pH of the immobilized enzyme is slightly higher, while their most suitable working temperatures are almost the same. The experiments show that the immobilization significantly improves the pH stability and thermal stability of laccase. The immobilized enzyme can be used repeatedly, and the remained activity is 40% after 10 times of reaction with the substrate. The results indicate that using the MCM-41 as a novel support material for laccase immobilization is favorable to the improvement on the stability and practicality of laccase.