Abstract: The effects of incubation time, temperature and moisture content on the production of glucoamylase by Aspergillus oryzae AO-01 were investigated on the results of one-factor at a time method. Then a response surface methodology (RSM) was used to optimize the above critical external factors, so as to find out the optimal conditions and the relationships among these factors. By solving the quadratic regression model equation with appropriate statistic methods, the optimal conditions of cultivation time, temperature and ratio of substrate to water are 32.8 h, 31.2℃ and 1:1.24 respectively. The production of the glucoamylase is increased from the lowest value of 656.2 U/g to 1645.1U/g wheat Qu. The experimental data under various conditions have validatedt het heoretical values.

Key words: Aspergillus oryzae, glucoamylase, Box-Behnken design, response surface methodology