Abstract: Laccase has been immobilized on chitosan with glutaraldehyde as crosslinking agent. The effects on the activity of immobilized laccase, such as concentration of glutaraldehyde, crosslinking time, laccase dosage and reaction time were studied. The results showed the optimal conditions of immobilization: the optimal glutaraldehyde concentration was 5%, the optimal crosslinking time was 8h, the optimal laccase dosage was 20mg/g carrier, and the optimal reaction time was 6h. On this condition, the recovery of enzyme activity was 52.2%. The results indicated that the optimal pH for immobilized laccase was around 4.5, which is lower than the best pH 5.0 for free enzyme. Compared with the free enzyme, its stability and repetition were considerably improved.

Key words: activity, retention, the optimal pH, stability

摘要： 以壳聚糖为载体，戊二醛为交联剂制备固定化漆酶，测定了不同戊二醛浓度、交联时间、给酶量以及固定化时间对固定化漆酶活性的影响。结果表明，固定化反应的最佳条件为戊二醛浓度5%，交联时间8h，给酶量20mg/g载体，固定化时间6h，在此条件下制备的固定化漆酶酶活性保持率为52.2%。此固定化漆酶具有最大活性时的溶液pH值在4.5，相比于自由漆酶的最佳pH值5.0，其向酸性偏移；与自由漆酶相比，固定化酶有很好的稳定性和可重复使用性。

关键词: 活性, 保持率, 最佳pH值, 稳定性