[Immobilization of lignin peroxidase on spherical mesoporous material]

The spherical mesoporous particles with two-dimensional (2D) hexagonal mesopores in diameter up to 11.6 nm was fabricated in acetic acid/sodium buffer solution (pH = 3.5) by using tetramethoxysilane (TMOS) as silica source, Pluronic P123 as template and 1,3,5-triisopropylbenzene (TIPB) as swelling agent. Then the mesoporous particles were employed as carriers for the immobilization of lignin peroxidase (LiP). The effect of immobilization time, the amount of added enzyme on the immobilized enzyme amount and activities were investigated. The characteristic and stability of immobilized LiP were also studied. The results showed that, as the mass ratio of enzyme (E) and mesoporous material (MS) was 76.8 mg/g,immobilizing time was 12 h, the largest immobilized enzyme amount (8.87 mg/g) and highest apparent activity (41.45 U/mg) of immobilization LiP were achieved. Comparing with free LiP, the optimum pH and temperature of the immobilized LiP were almost the same, while whose pH stability and thermal stability were significantly improved. No obvious activity loss was observed for the immobilized LiP after 7 weeks storage at 4 degrees C. After 6 times of usage, almost 30% of the initial activity could still remain.