多胺柔性链改性壳聚糖微球固定化木瓜蛋白酶

用反相悬浮交联法制备了单分散壳聚糖微球树脂,以其作为固定化载体基体,经氨基保护、C6羟基环氧化后接枝亲水性多乙烯多胺,制备了粒径为220～300μm、具有较高机械强度的多胺柔性链改性壳聚糖载体。采用该载体对木瓜蛋白酶在pH8.0缓冲液中室温下固定25h,固定化酶表观活力最高可达313U.g-1,活力回收率最高达61.5%,是采用未经多胺分子修饰的壳聚糖微球固定化的2.3倍。该柔性固定化酶的最适温度为65℃,最适pH为8.0,连续使用6～7次后仍保持原来活力的一半。

Immobilization of papain on flexible polyethylenamine chain modified chitosan microspheres

Monodisperse chitosan microspheres in the range 220μm to 300μm were prepared as support matrix for immobilized enzyme by phase-inversion suspension cross-linking technique firstly,then flexible polyethylenamine chain modified chitosan microspheres with more amino group content and better mechanical resistance were prepared by reaction of polyethyleneamine and epoxy-activated chitosan.Papain was immobilized on the support. The apparent activity of the immobilized Papain reached 313U/g under those immobilization conditions: pH 8.0, and reaction time 25h at room temperature.The most recovery of immobilized Papain activity reached 61.5% ,which was about 2.3 times that as immobilization on pure chitosan microsphere.The properties of the immobilized papain were also studied.The best application temperature and pH were 65℃and 8.0 respectively.When used continuously for 6～7 times,the activity of the immobilized papain would fall by nearly half.