壳聚糖固定糖化酶及其酶学性质研究

Immobilized Glucoamylase with Chitosan and Its Enzymatic Properties

以糖化酶为研究对象,壳聚糖为固定化材料,采用戊二醛作为交联剂对糖化酶进行固定化,研究了戊二醛浓度、糖化酶浓度和固定化时间对固定化效果的影响,并对比了糖化酶固定化前后其酶学性质的变化。结果表明,当戊二醛浓度1%,酶添加浓度6.0 g·L-1,固定化时间12 h时,糖化酶的固定化效果最好,其催化可溶性淀粉的酶活性为7 125.3 U’;糖化酶经过0.04 g·mL-1壳聚糖固定化后其酶学性质如催化最适温度、pH和米氏常数Km都发生了改变,分别为温度75℃、pH 5.4和Km值8 mg·mL-1;固定化酶连续使用4次后,其酶活性仍保持有最初固定化时酶活性的49.82%,说明其具有一定的重复使用性。

The research focused on the immobilization of glucoamylase using chitosan as immobilized carrier and glutaraldehyde as crosslinker. The effects of glutaraldehyde concentration, enzyme dosage and immobilization time on the immobilization were studied, and the enzymatic properties of free glucoamylase and immobilized glucoamylase were compared. The results showed that, the optimal conditions for immobilization were: glutaraldehyde concentration 1%, enzyme dosage 6.0 g·mL^-1, and immobilization time 12 h. Under the optimal conditions, the activity of immobilized enzyme catalyzing soluble starch was 7 125.3 U’. And its enzymatic properties including the optimal catalytic temperature, pH and michaelis constant Kmhad changed after the immobilization with 0.04 g·mL^-1 chitosan, they were 75 ℃, pH 5.4 and Km8 mg·mL^-1, respectively. After being used 4 times continuously, the activity of immobilized enzyme still remained 49.82% of original immobilized enzyme activity, which suggested that the immobilized enzyme had certain reusability.