The Aspergillus oryzae 2336 was taken as the original strain after three generation treatment with ultraviolet, and adopting a rapid screening method, the mutant strain F31012 was obtained. The fermentation condition of the F31012 was studied in this paper. Through the orthogonal test, the results showed that the optimum culture medium composition (%)was :corn starch 10, yeast lixivium 0.2; K 2HPO 4 0 1%, MgSO 4·7H 2O 0 05%, KCl 0 05%,pH 6 0; The volume of inoculation was about 15%; 300ml shak...