壳聚糖-埃洛石纳米管微球的制备及其对木瓜蛋白酶的固定化

运用交联-吸附法制备壳聚糖-埃洛石纳米管(chitosan-halloysites nanotube,CTS-HNTs)复合微球固定木瓜蛋白酶,并通过傅里叶红外光谱、扫描电子显微镜、荧光标记等方法进行表征。2%CTS+1%HNTs制备的微球对木瓜蛋白酶的固定量最高。固定化条件为木瓜蛋白酶质量浓度1 mg/mL、固定化时间10 h。固定化木瓜蛋白酶最适pH 6.8(游离酶pH 7.2)、最适温度60℃(游离酶50℃),保存30 d该酶相对活性为62%(游离酶27%),使用4次后,木瓜蛋白酶的相对活性仍然保留26.26%。CTS-HNTs微球固定化木瓜蛋白酶耐贮存,操作稳定性强,可以提高酶的利用率,降低酶解的成本,提高生产效率。

Preparation of Chitosan-Halloysites Nanotube Microspheres and Their Application in Immobilization of Papain

Chitosan-halloysites nanotube (CTS-HNTs) composite microspheres were successfully prepared by crosslinkingadsorption method, and used to immobilize papain. The successful immobilization of papain on CTS-HNTs composite microspheres was confirmed through infrared spectroscopy, scanning electron microscopy, and fluorescent labeling. The microspheres prepared with 2% CTS and 1% HNTs displayed the highest immobilization efficiency for papain. The optimal immobilization conditions were determined as 1 mg/mL and 10 h for papain concentration and immobilization time, respectively. The optimal pH and temperature for the immobilized enzyme were 6.8 and 60 ℃, respectively, while those for the free enzyme were 7.2 and 50 ℃, respectively. After 30 days of storage, the relative activity of the immobilized and free papain was 62% and 27%, respectively. The immobilized enzyme retained 26.26% of the initial activity after fourth repeated use. The immobilized papain had good storage stability and operational stability, enhancing the utility efficiency of the enzyme, cutting down the cost of enzymatic hydrolysis and enhancing the production efficiency.