磁性聚乙烯醇微球固定化α-乙酰乳酸脱羧酶

Magnetic polyvinyl alcohol (PVA) microspheres with 8—64 μm in diameter were prepared from PVA by dispersion and copolymerization with Fe3O4 as magnetite.There were more functional groups, such as hydroxyl and carboxyl etc. on the microsphere surface.1,1′-Carbonyldiimidazole (CDI), a carbonylating agent, was used for the activation of hydroxyl groups of PVA, and α-acetolactatedecarboxylase (ALDC) was immobilized onto the magnetic PVA microspheres by covalent bonding through the amino group.The results showed that total activity, protein binding, specific activity and activity retention of the immobilized enzyme were 63293 U·g -1, 72.67 mg·g -1, 870.96 U·mg -1 and 48.71%,respectively.The optimum temperature of immobilization enzyme was 50℃ and the optimum pH was 6.0.Compared with the free enzyme of ALDC, the thermal, operational and pH stability of the immobilized enzyme were improved.After being stored at 4℃, pH 6.0 for 31 days, the immobilized ALDC retained 95.7% of its initial activity which was 8% higher than the free enzyme.

磁性聚乙烯醇微球的制备及表征

为了制备表面具有羟基且有一定磁响应性的聚乙烯醇微球,本文采用反相乳化的方法,以液体石蜡为连续相,在Fe3O4磁流体存在下,通过戊二醛交联聚乙烯醇(PVA)。对微球的形貌,表面羟基含量,微球密度,微球Fe含量以及微球的磁响应性进行了研究。制得了粒径分布为25μm^150μm,表面羟值为11mmol/g^20mmol/g的磁性聚乙烯醇微球。

磁性聚乙烯醇微球的制备及其性质

采用分散聚合法，在Fe3O4磁流体存在下，通过PVA分子单体共聚制备磁性高分子微球。用透射电镜和X射线对磁流体的形貌、粒径进行表征和衍射分析，同时借助于显微拍照和红外光谱，对磁性微球的微观形貌和化学成分进行了研究。通过对比磁性微球的磁响应性及粒径，研究了反应温度、搅拌速度、聚乙烯醇用量、盐酸用量等操作因素对磁性微球性质的影响。结果表明，在70℃操作温度、750r／min的搅拌速度，5ml9％PVA和0．5ml37%盐酸条件下能制备出粒径在8～44μm之间、具有良好磁响应性、表面富含羟基和羧基等官能团的磁性聚乙烯醇微球。