功能化离子液体修饰的SBA-15固定化Burkholderia cepacia脂肪酶

Immobilization of Burkholderia Cepacia Lipase on Functionalized Ionic Liquids Modified Mesoporous Silica SBA-15

采用含不同碳链长度咪唑环的烷基功能化离子液体修饰介孔材料SBA-15,并通过X-射线衍射、元素分析、N2吸附-脱附、红外光谱和扫描电镜等方法研究了离子液体修饰对SBA-15结构的影响.以三乙酸甘油酯的水解为探针反应,考察了甲基、丁基、辛基等不同链长烷基取代咪唑类离子液体修饰的SBA-15固定化Burkholderia cepacia脂肪酶(BCL)的酶活、最适反应条件及稳定性等酶学性质.结果表明,离子液体修饰后材料保持了原有的介孔结构,其固定化酶对温度及低pH的敏感度降低,比活力及稳定性均显著提高.其中甲基功能化离子液体修饰的SBA-15固定化酶的比活力最高,是原粉SBA-15固定化酶的2.4倍;辛基功能化离子液体修饰的SBA-15固定化酶的热稳定性、储存稳定性、重复使用性及有机溶剂耐受性最佳.

Mesoporous silica SBA-15 was modified by imidazole-based ionic liquids with alkyl group. The modified support samples were characterized by nitrogen adsorption-desorption, small-angle X-ray diffraction, Fourier transform infrared spectroscopy, elemental analysis, and scanning electron microscopy. The samples were used to immobilize Burkholderia cepacia lipase （BCL） and the influence of alkyl chain length of ionic liquid on enzymatic properties was investigated by the hydrolysis reaction of triacetin. The results revealed that functionalized ionic liquid modification did not destroy the structure of SBA-15. Compared with the immobilized lipase on parent SBA-15, the immobilized lipases on modified support samples were less sensitive to temperature and low pH and showed higher specific activity and stability. There- into, BCL immobilized on methyl-functionalized ionic liquid modified SBA-15 had the highest specific activity, which improved 2.4 folds compared with BCL immobilized on SBA-15. BCL immobilized on octyl-functionalized ionic liquid modified SBA-15 had the best thermal stability, reusability, storage stability, and stability in organic solvent.