Abstract: Laccase was immobilized on the silanized magnetic silica nanoparticles by using glutaradehyde as the cross-linker. Immobilization of laccase was investigated and its immobilizing conditions were optimized. The results were achieved with the concentration of 8% glutaradehyde, immobilizing time of 6 h, the buffer of pH 7.0 and initial laccase concentration of 0.15 g/L. The optimum pH and temperature of immobilized laccase were 4.0 and 20℃, respectively. After the immobilized enzyme was kept at 60℃ for 4 h, it remained 60.9% of its initial activity. The immobilized laccase could retain above 55% of activity after 10 consecutive operations. The experimental results showed that the thermal stability and operational stability of immobilized laccase were improved in comparison with free laccase.

Key words: magnetic silica, nanoparticle, laccase, immobilization

摘要： 以氨基修饰的磁性SiO2纳米粒子为载体，通过交联剂戊二醛固定漆酶，对固定化条件进行了优化，比较了固定化酶与游离酶的酶学性质. 结果表明，漆酶固定化的最佳条件为戊二醛浓度8%(w)，固定化时间6 h，缓冲液pH值7.0，初始酶液浓度0.15 g/L. 固定化的漆酶的最适pH为4.0，最适温度为20℃. 在60℃条件下保温4 h，固定化漆酶仍能保持酶活力60.9%，在连续10次操作后，酶活力仍能保持55%以上，其热稳定性和操作稳定性均比游离酶高.

关键词: 磁性SiO2, 纳米粒子, 漆酶, 固定化