Penicillium sp.ZD-Z1 Chitosanase Immobilized on DEAE Cellulose by Cross-linking Reaction Zheng Lianying, Xiao Yuliang (Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027) Abstract Chitosanase obtained from Penicillium sp.ZD-Z1 was immobilized on DEAE cellulose with glutaraldehyde by cross-linking reaction. The optimal ratio of immobilization were as following: 0.1g DEAE cellulose was treated with 5mL 5% glutaraldehyde solution, then 2.3mg chitosanase was immobilized on the carrier. The optimal temperature and pH was 60°C and 4.0, and the Km value was 18.87g/L. Under the optimal conditions, the activity of immobilized enzyme is 1.5U/g, and the recovery of enzyme activity is 81.3%. After immobilization, the optimal temperature and Km value increased (from 50°C to 60°C, from 2.49g/L to 18.87g/L), whereas the optimal pH reduced (from 5.0 to 4.0). All of these indicated that the effect of intraparticle diffusion resistance for chitosanase’s kinetic property is greater than that of carrier’s electrical property. The enzyme activity loss was less than 15% after 10 times batch reaction, the immobilized enzyme showed good stability in operation Key words DEAE cellulose, Immobilization, Chitosanase, Chitosan 壳聚糖酶的 DEAE 纤维素固定化与性质研究 郑连英 肖玉良 (浙江大学化学工程与生物工程学系 杭州 310027) 摘要 以 DEAE 纤维素为载体、戊二醛为交联剂固定壳聚糖酶，确定了交联剂的最佳用量为 100mg DEAE 纤维素与 5mL 5%戊二醛交联，酶与载体的最佳比例为 23mg 酶/g DEAE 纤维素，固定化酶的最适温度和 pH 分别为 60°C 和 4.0，其米氏常数为 18.87g/L；所得固定化酶活力可达 1.5 U/g、酶活回收率可达 81.3%。壳聚糖酶在经固定化后，最适温度从 50°C 升高到 60°C、最适 pH 从 5.0 下降到 4.0、米氏常数从 2.49g/L 升高到 18.87g/L，说明酶经固定化后所产生的空间扩散阻力对壳聚糖酶的动力学性质的影响要比在固定化过程中所用载体所带的电荷的极性对酶的动力学性质的影响大得多。此外将该固定化酶重复使用十次，酶活力损失小于 15%，该固定化酶具有较好的操作稳定性。 关键词 DEAE 纤维素 固定化 壳聚糖酶 壳聚糖 郑连英 女，56 岁，副教授，从事生物工程方向的科研和教学工作。E-mail: zhengly@cmsce.zju.edu.cn 国家自然科学重点基金(50233020)、浙江省自然科学基金(200075)资助项目 2003-06-05 收稿，2003-09-10 接受 (PDF全文下载c04032)