固定化脂肪酶的创制及其在乙酸肉桂酯无溶剂制备中的应用

Preparation of Immobilized Lipase for the Solvent-free Synthesis of Cinnamyl Acetate

采用模板法结合辛基(C_(8))表面修饰制备疏水有序介孔SiO_(2)载体(OMS-C_(8)),在此基础上制得固定化脂肪酶(CSL@OMS-C_(8)),成功应用于乙酸肉桂酯的无溶剂酶法制备。利用扫描电镜(SEM)、透射电镜(TEM)、N_(2)-吸附脱附、傅里叶红外(FTIR)对载体材料和固定化酶进行表征。结果显示,OMS具有整齐有序的介孔结构,比表面积达149.9 m^(2)/g,平均孔径为15 nm。经过疏水改性后,接触角从20°提高到120°。优化获得了乙酸肉桂酯的最佳反应条件为温度50℃,肉桂醇与乙酸乙烯酯的摩尔比1∶5,固定化酶添加量2 g/L,反应时间2 h,转化率达到96.6%。催化剂经过5次重复使用肉桂醇的转化率仍能达到80%。

Hydrophobically ordered mesoporous SiO_(2)(OMS)carrier was prepared by template method combined with octyl surface modification,and immobilized lipase was prepared on this basis(CSL@OMS-C_(8)),which was successfully applied to the solvent-free enzymatic preparation of cinnamyl acetate.Scanning electron microscope(SEM),transmission electron microscopy(TEM),nitrogen gas adsorption analyzer,Fourier transform infrared(FTIR)and contact angle goniometer were employed to characterize the carriers and immobilized enzyme.The results showed that OMS has ordered mesoporous morphology with a specific surface area of 149.9 m^(2)/g and corresponding average pore diameter of 15 nm.The hydrophobicity of the material was greatly improved after hydrophobic modification with the contact angle increased from 20°to 120°.The optimal reaction conditions were obtained by optimizing the reaction conditions of enzymatic transesterification:reaction temperature was 50℃,molar ratio of cinnamyl alcohol to vinyl acetate was 1∶5,catalyst addition was 2 g/L,reaction time was 2 h,and the conversion rate reached 96.6%.Besides,the CSL@OMS-C_(8)maintained 80%conversion for cinnamyl alcohol after five-cycle reuse.