基于聚乙烯醇/Fe2O3纳米颗粒的纤维素酶固定化

以聚乙烯醇/Fe2O3磁性纳米颗粒为纤维素酶固定化载体, 通过反复冻融的方法成功地实现了纤维素酶固定化. 采用透射电镜、红外光谱仪、振动样品磁强度计对固定化酶复合体进行了表征, 结果显示, 固定化酶复合体为大小约1 μm的微凝胶团, 内含10 nm左右的Fe2O3纳米颗粒. 研究影响固定化因素后发现, 当pH为6, 固定化时间为11 h, 纤维素酶/PVA质量比为4, PVA/Fe质量比为50时, 固定化纤维素酶效果最好. 通过该方法固定后酶活回收率达42%, 酶水解效率显著提高, 经过5次反应后的固定化酶相对酶活力保留50%以上. 因此, 基于聚乙烯醇/Fe2O3纳米颗粒的纤维素酶固定有利于酶的循环使用并显著提高酶的使用效率, 是一种有效固定化纤维素酶的新方法.

Immobilization of Cellulase Based on Polyvinyl Alcohol/Fe2 O3 Nanoparticles

To improve the enzyme activity and reusability, a new soluble, easy separated carrier was made to immolize cellulase. The immobilized cellulase based on polyvinyl alcohol/Fe2O3 nanoparticles was prepared with cyclic freezing thawing process. Analytic data from TEM, IR and VSM detection suggest that the average diameters of immobilized cellulase complexs were 1 μm, which contained about 10 nm Fe2O3 naoparticle. The factors affecting the activities of immobilized cellulase were researched. The activity retention of immobilized cellulase was achieved as 42% under the optimum conditions: pH=6.0, mass ratio of cellulase to PVA is equal to 4, mass ratio of PVA to Fe is equal to 50, 11 h for immobilization. The immobilized cellulase exhibited greater efficiency than free one and retained 50% relative activity after five times of cycled reuse, which indicates that this novel method of immobilization could be propitious to cellulase reuse and efficiency improvement.