介孔SiO2的改性及对诺维信漆酶的交联固定化

采用十六烷基三甲基溴化铵(CTAB)为模板剂,四乙氧基硅烷(正硅酸乙酯,TEOS)为硅源,硝酸为催化剂来制备介孔SiO2,并采用后嫁接法对介孔SiO2进行氨基化改性。利用红外光谱(IR),X射线粉末衍射(XRD),差热-热重分析(DTA-TG),扫描电镜(SEM),元素分析,微电泳法及N2吸附-脱附方法对改性前后的产物进行表征。结果表明氨基已成功嫁接到介孔SiO2孔道中,改性后的介孔SiO2有序度有所下降,但仍为介孔材料;改性之后介孔材料的孔径、比表面积、孔体积均变小。等电点由原来的2.74变为4.75。本文还以氨基修饰的介孔SiO2为载体,通过交联剂戊二醛固定诺维信(Novozymes)工业级漆酶,并采用正交设计法对固定化条件进行了优化。研究表明漆酶经固定化后,其操作稳定性比游离酶高。

Modified Mesoporous Silica: Synthesis and Immobilization Function for Novozymes Laccase

Mesoporous silica was prepared by using hexadecyl trimethyl ammonium bromide (CTAB) as the template, tetraethoxysilane (tetraethylorthosilicate, TEOS) as the silicon source and nitric acid as the hydrolysis catalyst. The obtained sample was then modified via post grafting method. The mesoporous silica before and after modification was characterized by IR, DTA-TG, XRD, SEM, elemental analysis, micro-electrophoresis and N₂ adsorption-desorption. The results show that the mesoporous silica has been modified by amino-groups, the material after modification still belongs to a family of mesoporous materials in spite of a slight decrease in the order degree. The surface area, pore size and pore volume become smaller, and the isoelectric point is decreased from 2.74 to 4.75 after the modification. The commercial Novozymes laccase is successfully immobilized in the inner surface of amino-functionalized mesoporous silica in this work by using glutaraldehyde as the crosslinking agent. The conditions of immobilization on amino-functionalized mesoporous silica were optimized by means of orthogonal experimental designs. The results show that the operational stability of the immobilized enzyme is significantly improved in comparison with the free enzyme.