硅藻土强化吸附壳聚糖固定化青霉素酰化酶

Immobilization of penicillin acylase by intensive adsorption of chitosan on celite

文中针对壳聚糖颗粒机械强度不够和比表面积不大的缺点 ,用无机多孔材料硅藻土 (celite)在低压下强化吸附壳聚糖 ,再用戊二醛使其活化 ,以此为载体通过共价结合固定化青霉素酰化酶。以酶活和回收率为指标 ,讨论了活化、固定化及酶反应的不同条件对固定化青霉素酰化酶的酶活和回收率的影响。当戊二醛溶液质量分数为5 %、pH值为 8 5 ;酶固定化温度为 2 7℃ ,固定化pH值为 7 6 ,固定化时间为 12～ 18h时 ,为最佳固定化条件。固定化酶的酶活可达 10 0 0 0mol/s左右 ,回收率约为 4 0 %。固定化酶的储存稳定性和热稳定性好 ,载体有良好的强度。

This issue described a new method of immobilization of penicillin acylase(PA) to overcome the shortcomings of low mechanical intensity of chitosan matrix and to increase its specific area, and the inorganic material celite was selected as a carrier. Under the low pressure, the chitosan solution could be absorbed into the surface of the celite. The absorbed chitosan was further activated with glutaraldehyde. Immobilization of enzyme on the chitosan was accomplished by covalent linking. The effects of different conditions for crosslinking, immobilizing and reacting on the activity and the yield of the immobilized PA were discussed. When the mass fraction of glutaraldehyde was 5%, pH of glutaraldehyde was 8.5; temperature, pH and time of PA for immobilizing was 27℃, 7.6 and 12～18h respectively, the activity and the yield of immobilized PA were around 10000mol/s and around 40% respectively. The immoblized PA on the chitosan has a long shelf-life and a good thermal stability. The mechanical intensity of the matrix is satisfactory.