自组装磁性聚苯乙烯微球固定化木瓜蛋白酶

通过逐层自组装（Layer-By-Layer self-assembly）的方式在自制的经过磺化的聚苯乙烯微球上连接高分子电解质和磁性物质制备了磁性微球，并用此磁性微球固定化木瓜蛋白酶。研究了固定化酶的最优工艺条件（固定化率最高）为：0.5g液态分散磁球(固含量为7.9%)，温度30℃，给酶量15mg，pH值为6.0，固定化时间1.0h，此时可达非常高的固定化率93.0%。并且研究了固定化酶的性质：最佳使用温度为50℃，最佳使用pH值8.0，使用3次或80℃保存1.5~2.0h活性大约降为一半。

Study on immobilization of papain by layer-by-layer self-assembly on magnetic PS microspheres

Using sulfate-stabilized polystyrene (PS) latex particles, magnetic microspheres are prepared as a support for enzyme immobilization through layer- by -layer self-assembly. Papain is then immobilized on it. The best circumstance (when the ratio of enzyme immobilization is the largest) of enzyme immobilization has been studied .That is as follows : pH 6.0, 1.0h, 30℃, 25mg native free enzyme/0.5g liquid and disperse magnetic microspheres with solid content of 7.9%. Then the largest ratio of enzyme immobilization could reach 93.0%. The properties of immobilized enzyme have also been studied. The results are as follows: the best application tempreture and pH are 50℃ and 8.0; When used for 3 times or reserved 1.5~2.0h at 80℃, the activity would fall to nearly a half.