MOFs包封纤维素酶的制备及性能研究

Research and preparation of cellulase encapsulated in metal-organic frameworks

本研究采用原位封装技术首次将纤维素酶固定在金属-有机框架材料(MOFs)内,制备出一种锌基MOFs包封纤维素酶的复合材料(纤维素酶@ZIF-8)。原位封装法不仅可以提高酶与载体的结合强度,还可增加酶的负载量,本研究中纤维素酶在ZIF-8中的负载量高达350mg/g。酶活性评价结果显示,纤维素酶@ZIF-8对碱性环境的耐受程度显著提高,特别是在pH 8的反应条件下,固定化酶仍有65%的相对酶活性,而游离酶仅为10%。孔径测定中的介孔分布进一步证明了纤维素酶被有效封装在ZIF-8框架内,由于酶的引入导致ZIF-8的微孔结构产生缺陷而构建出介孔,更有利于后续酶催化反应中物质的自由扩散。

A new immobilized cellulase was firstly prepared by in-situ encapsulating in Zn-metal-organic frameworks,named cellulase@ZIF-8.The in-situ encapsulation could enhance the anchoring strength between cellulase and ZIF-8.The loading of cellulase was also increased in this study,and the highest loading was up to 350mg/g.Moreover,cellulase@ZIF-8 showed superior tolerance to base environment,and it could keep 65%enzyme activity at pH8,whereas the free cellulase had only 10%.The meso-porous distribution in cellulase@MOFs further proved that the cellulase was successfully encapsulated in the frameworks of ZIF-8.Because ZIF-8 was micro-porous,the cellualse introduction caused structural defects of ZIF-8 resulting in meso-porous.