改性壳聚糖固定化脂肪酶的研究

Immobilization of Lipase by Chemical Modified of Chitosan

摘要:

以化学改性后的壳聚糖为载体固定假丝酵母99-125脂肪酶，研究了不同的活化剂对壳聚糖表面羟基基团的活化程度，及以活化后壳聚糖为载体采用不同固定化方法对假丝酵母脂肪酶固定效果的影响。结果表明1-乙基-3-（3-甲基氨基）丙基碳二亚胺可有效的活化壳聚糖表面羟基，活化后的壳聚糖表面氨基与戊二醛偶联后形成的壳聚糖为良好的脂肪酶固定化载体，其固定脂肪酶的水解活力可高达86.8U/g。此外，还对影响固定化进程中的各种因素进行了研究，确定最优条件，比较了固定化前后酶的热稳定性、有机溶剂稳定性及最适反应温度。并考察了该固定化脂肪酶催化合成棕榈酸十六酯的操作稳定性，结果表明，连续反应16批之后棕榈酸十六酯的转化率仍能达到85%以上。

Abstract:

Lipase (EC3.1.1.3) from Candida sp.99-125 was immobilized on chitosan by chemical covalence. Lipase was first immobilized to chitosan beads by activating its hydroxyl groups with carbodiimide followed by cross-linking more lipase to the amino groups with glutaraldehyde. In this article, different factors that influenced the immobilization were investigated, and the optimum conditions were ascertained. Comparative studies of organic solvent and thermal stability between free lipase and immobilized lipase were conducted. Immobilization enhanced the lipase stability against changes of temperature and organic solvent. Immobilization lipase can be reused in the synthesis system of palmitate hexadecyl. Operational stability tests indicated that the immobilized lipase occurs after 16 consecutive batches, the conversion rate remained 85%. Such results revealed good potential for recycling under esterification system.