The immobilized condition of lipase onto magnetic chitosan microspheres by cross-linking with glutaldehyde was optimized and the immobilized lipase was characterized. The optimum immobilizing time was 7 h, the optimum pH was 8, the optimum temperature was 50 ℃, and the optimum lipase amount were added 10 mg in 100 mg microspheres. Compared with free lipase, the thermal and acid-basic stabilities of immobilized lipase were increased appreciably. After 5 recycle of hydrolyzation, the activity of immobilized lipase remained 82.6％ of its initial activity. Magnetic chitosan microsphere was a kind of good support for immobilizing lipase.%以纳米级磁性壳聚糖微球为载体,戊二醛为交联剂固定化脂肪酶,对固定化脂肪酶条件进行优化,同时对固定化脂肪酶的理化性质、活性回收率、热稳定性和储存稳定性进行研究.结果表明,固定化脂肪酶的最佳时间为7 h,最佳pH为8,最佳温度为50 ℃,最佳酶加量为每100 mg磁性微球加酶10 mg.和自由酶相比,脂肪酶被磁性壳聚糖固定化后其热稳定性、pH稳定性均得到明显提高.固定化脂肪酶重复使用5次,仍然保持82.6%相对活力.磁性壳聚糖微球是固定化脂肪酶的良好载体.
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