Mesoporous silicas synthesis and application for lignin peroxidase immobilization by covalent binding method

Immobilization of enzymes on mesoporous silicas (MS) allows for good reusability. MS with two-dimensional hexagonal pores in diameter up to 14.13 nm were synthesized using Pluronic P123 as template and 1,3,5-triisopropylbenzene as a swelling agent in acetate buffer. The surface of MS was modified by the silanization reagents 3-aminopropyltriethoxysilane. Lignin peroxidase (LiP) was successfully immobilized on the modified MS through covalent binding method by four agents: glutaraldehyde, 1,4-phenylene diisothiocyanate, cyanotic chloride and water-soluble carbodiimide. Results showed that cyanotic chloride provided the best performance for LiP immobilization. The loaded protein concentration was 12.15 mg/g and the immobilized LiP activity was 812.9 U/L. Immobilized LiP had better pH stability. Acid Orange II was used to examine the reusability of immobilized LiP, showing more than 50% of the dye was decolorized at the fifth cycle.