氨基多糖多孔微球载体制备及其脲酶固定化特性

以脱乙酰度为 95 % ,分子量分别为 98KDa和 1 1 30 KDa的氨基多糖为载体材料 ,采用三聚磷酸钠固定的方法制成氨基多糖微球 ,并以此氨基多糖微球为载体用戊二醛交联法进行脲酶固定化研究。结果表明 :在 3%复合氨基多糖溶液中大、小分子量氨基多糖质量比为 1∶ 5时微球载体机械强度较好 ,表面光滑。用 Ca CO3 (w/w=1 /1 )处理则可得到表面具有蜂窝状结构的多孔微球载体 ;光滑表面微球载体与多孔微球载体对脲酶的固定化效率分别是 5 1 .5 %和 6 8% ;用 1 .5 cm× 1 5 cm柱进行尿素转化时间 1 2 min,光滑表面微球载体固定化脲酶和多孔微球载体固定化脲酶对尿素溶液(30 0 mg/L)转化率分别为 91 .8%和 99.99%。这一结果说明 ,利用多孔微球载体可有效地提高载体对脲酶的固定化效率 ,并且能彻底的分解尿素 ,提高尿素转化率

Preparation of Chitosan Microspheres and Their Characteristics in Immobilized Urease

Chitosan C(MW=98KDa) and chitosan D(MW=1 130KDa) are formed into microspheres by the reaction between chitosan and TPPNa. Urease is immobilized onto the chitosan microspheres with glutaraldehyde. The chitosan microspheres have smooth surfaces and better mechanical intensity at the concentration of chitosan 3% and C/D=5/1(w/w). Porous chitosan microspheres were formed by adding CaCO 3 (chitosan/CaCO 3=1/1,w/w) into the reaction system. The urease immobilization efficiency on smooth surface chitosan microspheres and porous chitosan microspheres is 51.5% and 68%, respectively. When the system reacted for 12 min, the urea (300 mg/mL ) conversion rate of the immobilized urease of smooth surface chitosan microspheres and porous chitosan microspheres is 91.8% and 99.99%, respectively. The results show that the porous chitosan microspheres can improve both the immobilization efficiency of urease and the conversion rate of urea.