壳聚糖微球固定化脂肪酶的制备工艺及应用性质研究

Preparation of Chitosan Immobilized Lipase and Enzyme Characterization

以壳聚糖微球为载体,采用乙基[3-(二甲胺基)丙基]碳二亚胺盐酸盐(EDC)活化羟基固定Candida rugosa脂肪酶,测定了不同EDC浓度、给酶量以及固定化时间对固定化脂肪酶活性的影响,并与戊二醛固定化脂肪酶性质作了对比分析。研究结果表明,用EDC活化固定化脂肪酶,当缓冲液pH为7,加酶量达到30 mg,EDC浓度为0.2%,交联时间6 h,固定化脂肪酶最大比活力为26.1 U/mg蛋白、活力回收最高为65.5%。固定化酶的热稳定性、pH稳定性和重复使用稳定性都有较大提高。壳聚糖微球固定化酶合成油酸乙酯循环使用次数达6次,油酸乙酯转化率从66.4%降至26.5%。

Lipase was immobilized on chitosan beads by activating the hydroxyl groups of chitosan using carbodiimide coupling agent. The effects of earbediimide concentration, lipase dosage and immobilization time on the lipase characteristics were investigated. The ehitosan immobilized lipase was compared with the lipase immobilized with the method of glutaraldehyde cross - linking. Results show that the maximum specific activity of 26.1 U/rag - protein and activity recovery of 65.5% for the ehitosan immobilized lipase are obtained at the conditions of carbodiimide concentration 0.2%, enzyme dosage 30 rag, pH 7 and emsslinking time 6h. It is a great improvement for the thermal stability, pH stability and reuse stability of immobilized lipases. The ehitosan immobilized lipase microspheres could be used for 6 times in synthesis of ethyl oleate, and the conversion rate lowers from 66.4 % to 26.5 %.