壳聚糖/卵磷脂复合微球固定木瓜蛋白酶的研究

以壳聚糖和卵磷脂为材料,采用乳化-交联法制备壳聚糖/卵磷脂复合微球,并用光学显微镜和红外光谱对微球进行表征；再以此微球作为载体固定木瓜蛋白酶,以固定率为指标,应用正交试验法优选固定化酶的制备工艺,并对固定化酶的半衰期、米氏常数(Km)、操作稳定性进行研究.结果表明,制备的壳聚糖/卵磷脂复合微球呈完整的圆球形或椭球形；固定化酶的优化制备工艺为:m(壳聚糖)=250 mg,m(壳聚糖):m(卵磷脂)=1:2,V(戊二醛水溶液)=300 μL,m(木瓜蛋白酶)=20 mg,此时制备的固定化酶的固定率达61.94％,半衰期为86.27 h,米氏常数为6.37 mg/mL,固定化酶有很好的操作稳定性.

Study of immobilization of papain with chitosan/lecithin microspheres

Chitosan(CS)/lecithin microspheres were prepared with the CS and lecithin by emulsion-crosslinking method.The microspheres were characterized by optical microscope and IR,and used as carrier for immobilization of papain.Taking the extent of immobilization of papain on the microspheres as index,orthogonal test was carried out to optimize the preparation process.Half life period,Michaelis constant(Km) and operation stability of immobilized papain were studied.The results showed that the shape of CS/lecithin microspheres was complete spherical or ellipsoidal.The optimum conditions were:m(CS)=250 mg,m(CS):m(lecithin)=1:2,V(glutaraldehyde aqueous solution)=300 μL,m(papain)=20 mg.In this case,percentage of immobilized papain achieves 61.94%;half life period achieves 86.27 h;Km=6.37 mg/mL;the immobilized papain had a good operational stability.