多孔化CLEAs催化降解壳聚糖制备活性低聚糖

Degradation of Chitosan to Produce Bioactive Oligomers Catalyzed by the Porous CLEAs

针对传统交联酶聚体(CLEAs)催化大分子底物传质限制严重的问题,作者利用多孔化CLEAs(p-CLEAs)实现了壳聚糖酶法降解制备生物活性低聚糖。相同条件下p-CLEAs催化所生成还原糖量是游离酶的85%,是传统CLEAs的4倍。p-CLEAs所具有的多孔化结构造成了反应物相对分子质量和多分散性指数具有与游离酶催化不同的变化规律。通过控制酶解时间,结合超滤膜分离得到了相对分子质量为5 000~10 000的低聚糖产品,占总酶解产物质量的67.5%。抑菌性实验发现,当低聚壳聚糖(5 000~10 000)质量浓度为0.275 mg/m L时,对金黄色葡萄球菌和大肠杆菌达到完全抑制。

In order to overcome the defect of low catalytic efficiency of conventional cross-linked enzyme aggregates （CLEAs） toward macromolecular substrate,porous CLEAs （p-CLEAs） was applied in the degradation of chitosan to produce bioactive chitosan oligomers. The reducing sugar concentration was 85% of that catalyzed by free papain,which is 4 times higher than the conventional CLEAs under the same condition. Molecular weight and polydispersity index displayed the particular properties in the degradation of chitosan catalyzed by p-CLEAs compared with free papain. By controlling the degradation time,67.5% （wt） of the oligomer product （5-10 kD） were obtained through ultrafiltration membrane separation. Staphylococcus aureus and Escherichia coli can be totally suppressed when the concentration of oligomers （5-10 kD） was 0.275mg/mL.