SiO2/海藻酸钠复合水凝胶作为固定化纤维素酶载体

以海藻酸钠和γ-氨丙基三乙氧基硅烷为原料，在一定条件下使二者发生交联反应生成复合水凝胶，并以此复合凝胶作为固定化纤维素酶的载体。纤维素酶的包埋率超过了85%， 酶固定前后的SEM图表明纤维素酶非常均匀地分布在载体中。探讨了pH、 温度对固定化酶和游离酶活力的影响， 结果表明固定化酶具有对pH和温度更高的稳定性， 固定化酶的最适宜pH为3.6，最佳催化温度为50℃。通过Michaelis Menten（米氏）方程计算得到的固定化酶的米式常数（K_m）值较游离酶大，表明固定化酶的可重复使用性和储藏稳定性良好，连续使用10次后依然保留>50%酶活力，储藏1个月后固定化酶依然有81%的相对酶活力。 

SiO2/alginate gel biocomposites for cellulase immobilization

SiO2/alginate gel composites derived from 3-aminopropyltrimethoxysilane and sodium alginate were prepared through covalent cross-linking reaction. The gel biocomposites were used as carriers for the immobilization of cellulase. The loading efficiency (%) of the immobilized cellulase exceeds 86%,  and the SEM photographs show that the cellulase is distributed  homogeneously  in the carriers. The activities of the free cellulase and immobilized cellulase were determined by measuring the amount of the glucose made from carboxymethyl cellulase under the given conditions. The results show that the immobilized cellulase has a higher Michaelis constant( Km) than free cellulase. The immobilized cellulase has better stability with respect to pH and temperature than the free cellulose. The optimal pH  of enzyme is 3.6 and the optimal temperature of enzyme is 50℃.The storage and recycling stability of the cellulase increase after immobilization, it also remains up to 50% relative activity after 10 cycles and remains 81% relative activity after being stored for 30 days.