Purification and characterization of glucoamylase of Aspergillus oryzae from Luzhou-flavour Daqu.

Autor: Wang, Chuan, Yang, Lianli, Luo, Lunan, Tang, Shichao, Wang, Qiang
Předmět:
Zdroj: Biotechnology Letters; Nov2020, Vol. 42 Issue 11, p2345-2355, 11p
Abstrakt: Objective: To obtain novel glucoamylase from Daqu microbe. Results: A dominant strain known as LZ2 with high activity of hydrolyzing starch was isolated from Luzhou Daqu, a Chinese traditional fermentation starter. The LZ2 was identified as Aspergillus oryzae by 18S rDNA sequence analysis. Glucoamylase from LZ2, named as GA-LZ2, was purified to homogeneity and showed a single band with expected molecular mass of 60 kD. The GA-LZ2 effectively degraded amylose, rice starch and wheat starch. Optimal temperature and pH value of enzyme were 60 °C and pH 4.0 respectively. The GA-LZ2 displayed significant thermal stability and pH stability at moderate temperature and low pH. Intriguingly, the thermostability was enhanced in the presence of starch. In addition, GA-LZ2 exhibited insensitivity to glucose, independence of metal ions and tolerance to organic solvents. The GA-LZ2 retained complete activity in the presence of 100 mM glucose and 5% ethanol and methanol. Conclusion: Glucoamylase GA-LZ2 displayed broad substrate specificity, strong stability and tolerance, suggesting that GA-LZ2 carry potential for industrial application in bioethanol production. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index