二氧化硅/壳聚糖大孔复合材料固定化漆酶及其对2,4-二氯苯酚的降解

Laccase Immobilization with Silica/Chitosan Macroporous Composites and its Application in 2,4-Dichlorophenol Degradation

通过壳聚糖在块体Si O_2大孔材料孔壁上的吸附,制备二氧化硅/壳聚糖大孔复合材料(Si O_2/CS),经戊二醛交联后用于固定诺维信工业漆酶。优化漆酶固定化的实验条件并对比了游离漆酶和固定化漆酶的酶学性质。实验结果表明:在p H值为4.5、漆酶初始浓度为40 mg×m L^(-1)的条件下,固定化4 h效果最佳,固定化酶酶活回收率为85.5%;相对于游离漆酶,固定化漆酶的p H稳定性和热稳定性均得到明显提高,且具有良好的操作稳定性。应用固定化漆酶去除2,4-二氯苯酚(2,4-DCP),研究了降解时间、p H、温度和2,4-DCP初始浓度对其去除率的影响。在优化条件下,固定化漆酶对2,4-DCP(20 mg×L^(-1))的去除率为83.2%,固定化漆酶可重复使用,并且便于从反应体系中分离出来。

A new macroporous silica/chitosan（Si O2/CS） composite was prepared by adsorbing CS on pore wall of a large-sized macroporous silica, and it was employed as the support for the immobilization of commercial Novozymes laccase by using glutaraldehyde as the crosslinking agent. The best activity recovery of the immobilized laccase is 85.5% under conditions of buffer solution p H 4.5, initial laccase concentration 40 mg·m L^-1 and immobilizing time of 4 h. The p H and thermal stabilities of the immobilized laccase are significantly improved comparing to free laccase. Moreover, the immobilized laccase has good operational stability. The immobilized laccase was used to remove 2,4-dichlorophenol（2,4-DCP）, and the effects of degradation time, p H value, temperature and initial concentration of 2,4-DCP on 2,4-DCP removal rate were investigated. Up to 83.2% of 2,4-DCP（20 mg·L^-1） was removed under optimized conditions. The immobilized laccase has good reusability and can be easily recovered from the reaction system.