氨基二氧化硅固定化纤维素酶及其特性

Characteristic of the Cellulose Immobilized on Aminated SiO_2

以氨基化二氧化硅为载体,戊二醛为交联剂,采用共价交联法制备固定化纤维素酶,最佳条件为交联剂浓度4%(体积比),交联时间60分钟,给酶量35 U/g载体,固定化反应时间5小时。所得固定化酶对pH和温度的敏感性降低,时间稳定性和热稳定性均优于游离酶。热动力学研究表明,固定酶的失活活化能(Ed)、失活焓(△H*)和失活自由能(△G*)均高于自由酶,固定化减小酶失活反应速率,降低酶失活反应趋势。

The immobilized cellulase was prepared by using aminated SiO2 with glutaraldehyde as crosslinking agent. The best immobilized reacting condition were glutaraldehyde concentration of 4% （v/v）, crosslinking time for 60 minutes, cellulase dosage of 35 U/g and reaction time for 5 hours. The obtained immobilized cellulase displayed best enzyme activity. Compared with free cellulase, immobilized one had lower sensitivity to pH and temperature of reacting system and higher time stability and thermal stability. The immobilized cellulase had higer Ed, △H°, △S° and △G° to thermo inactivation reaction, which showed that the immobilization slowed down the inactivation velocity of cellulase and reduced the potentiality of inactivation reaction.