微胶囊法固定化糖化酶的研究

酶或细胞固定化技术是微生物发酵的主要手段之一,它可使生产速率和效率获得显著提高。为确定微胶囊法固定糖化酶的最佳条件,以壳聚糖和海藻酸钠为载体,采用微胶囊法固定糖化酶。试验结果表明,最佳固定化条件为:壳聚糖脱乙酰度为85%、海藻酸钠浓度为3%、戊二醛浓度为1.5%、氯化钙浓度为0.2 mol.L-1。固定化酶的最适作用温度为75℃,比游离酶提高了20℃,最适pH为4.5,比游离酶下降0.5个单位。固定化酶的活力最高达2 013.42 U.g-1干胶,相对活力为89.3%,米氏常数Km为1.28%,半衰期为223 h。采用壳聚糖和海藻酸钠为载体微胶囊法固定糖化酶的方法是可行的。

Immobilization of Glucoamylase with Chitosan and Sodium Alginate by Microencapsulation Method

Chitosan and sodium alginate were used as carrier to immobilize glucoamylase by microencapsulation method.The results showed that the optimum immobilization conditions were that chitosan deacetylation degree was 85%,sodium alginate concentration 3%,glutaraldehyde concentration 1.5%,calcium chloride concentration 0.2 mol·L-1.The optimum temperature of immobilized enzyme was 75 ℃,raised 20 ℃than the free enzyme's.the optimum pH 4.5,dropped 0.5 unit than the free enzyme's.The highest activity of immobilized enzyme reached 2013.42 U·g-1 dry gel,and its relative activity was 89.3%.The Km value was 1.28%,its half-life was 223 h.