海藻酸-SiO2杂化凝胶固定化洋葱伯克霍尔德茵脂肪酶的研究

利用四乙氧基硅烷（TEOS）原位水解法将SiO2掺杂于海藻酸（ALG）凝胶中，通过双交联制备出新型ALG—SiO2杂化凝胶以固定化洋葱伯克霍尔德菌脂肪酶。结果表明，固定化酶的最优条件：质量分数为2．0％的ALG、0．2mol／LCaCl2、V（ALG）／V（TEOS）为5、加酶量为1gALG加100mg酶粉、固定化60min、采用直径为0．8mm的针头滴定、真空冷冻干燥。在此条件下，酶蛋白的包埋率可达100％，酶活回收率可达91％。固定化酶的最适pH为8．0，最适作用温度为50℃，重复使用8次后，酶活性仍能保持80％以上。ALG—Si02杂化凝胶的场扫描电镜（FESEM）观察发现凝胶的整体构造仍然是海藻酸凝胶骨架；与ALG凝胶平滑的内部相比较，杂化凝胶仍具有完整的网络结构，但内部更为粗糙，结构更为致密。

Immobilization of lipase from Burkholderia cepacia with alginate-silica hybrid gel

Lipase from Burkholderia cepacia was entrapped in alginate-silica (ALG-SiO_2) hybrid gel prepared by hydrolysis of tetraethoxy silicone (TEOS) into alginate gel by double-cross-linking method. The optimal conditions were as follows: the concentration of sodium alginate and CaCl2 enzyme load was 100 mg/g carrier, immobilization time was 60 min, using 0.8 mm diameter needle for titration, and vacuum freeze-dried. Under the optimal conditions, the immobilization efficiency reached 100%, and the activity recovery was 91%. ALG-SiO_2 hybrid gel observed by field scanning electron microscope showed that the overall gel structure remained alginate gel skeleton, many small particles distributed inside the ALG-SiO_2 hybrid gel. ALG-SiO_2 hybrid gel interface appeared coarser and the overall structure becoming more compact as compared with ALG gel.