葡萄糖异构酶固定化细胞的制备方法优化及应用

Studies on the optimization of immobilized cell with glucose isomerase and its application

本研究比较了壳聚糖微球法、聚乙烯醇-海藻酸钠包埋法、微晶纤维素法及壳聚糖絮凝-戊二醛交联法对含有葡萄糖异构酶细胞的固定化效果,发现壳聚糖絮凝-戊二醛交联法效果最好。最佳固定化条件为:壳聚糖浓度为0.015%(m/v),戊二醛浓度为0.05%(v/v),交联时间为3 h。采用该方法制备的固定化细胞的酶活为2579 U·g-1,酶活回收率为70.5%,机械强度为1797 g。在分批转化方面,固定化细胞在70℃下重复使用8批次后,转化率仍保持在42.1%以上。此外,固定化细胞在连续柱式转化反应器中连续转化19天,转化得到了约5.7 kg果糖。

The recombinant cells with glucose isomerase were immobilized by using four different immobilized methods. Upon the comparison of enzyme activity, activity recovery and hardness of the immobilized cells, the flocculation - crosslinking method was chosen for the subsequent experiments. It found that the optimal condition for the immobilization was 0. 015% （m/v） chitosan solution and 0. 05% （v/v） glutaraldehyde solution with 3 hours of crosslinking reaction. The maximum activity and activity recovery for the immobilized cells were 2579 U · g^-1 and 70. 5% , respectively. And the hardness of immobilized cells was 1797 g. Then the immobilized cells were used for the production of fructose in batch operation. It showed that the conversion rate of glucose to fructose was 42. 1% at the end of eighth cy- cle. The immobilized cells converted 5.7 kg glucose after 19 days reaction if the operation system.