Affiliation:
1. Liquor Brewing Biotechnology and Application Key Laboratory of Sichuan Province Sichuan University of Science and Engineering Yibin Sichuan China
2. College of Bioengineering Sichuan University of Science and Engineering Yibin Sichuan China
Abstract
AbstractThe glucoamylase@ZIF‐8 was prepared using ZIF‐8 material as the carrier in this study. The preparation process was optimized by response surface methodology, and the stability of glucoamylase@ZIF‐8 was determined. The material was characterized by scanning electron microscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy. The results showed that the optimum preparation process of glucoamylase@ZIF‐8 was 1.65 mol 2‐methylimidazole, 5.85 mL glucoamylase, 33°C stirring temperature, 90 min stirring time, and 84.0230% ± 0.6006% embedding rate. At 100°C, the free glucoamylase completely lost its activity, whereas the glucoamylase@ZIF‐8 still had a retained enzyme activity of 12.0123% ± 0.86158%; at pH 3–6, the highest activity of glucoamylase@ZIF‐8 was 95.9531% ± 0.96181%, and about 80% of glucoamylase activity could be retained under alkaline conditions. When the ethanol concentration was 13%, the retained enzyme activity was 7.9316% ± 0.19805%, significantly higher than free enzymes. The Km of glucoamylase@ZIF‐8 and free enzyme were 1235.6825 and 80.317 mg/mL, respectively. Vmax was 0.2453 and 0.149 mg/(mL min), respectively. The appearance, crystal strength, and thermal stability of glucoamylase@ZIF‐8 were improved after optimization, and they had high reusability.