Abstract
Among the selected strains of Aspergillus oryzae group, the strain No. 0-9-5 (which of Tokyo) gave excellent anfylase activity for the submerged production.. By using this strain, several resea-rches concerning the cultural environments affecting the amylase production were carried out. It was shown that the optimal initiall pH for incubation lay between 5 and 6 the activity markedly fell down under 4.0 and amylase action was completely inhibited or destroyed under 3.0. The incubation at 30°C was more favorable than at 25°C. When starch and peptone were taken as C and N sources, the optimal concentrations of both of these substrates were about 2 to 3%, NaNO3 and NH4NO3 were suitable inorganic N sources, because these substances played buffer actior during the incubation, viz., they prevented the acidification due to the acid production. As natura; organic N sources, rice bran, wheat bran, dry yeast and stillage showed the excellent results.
Amylase production, provided that the cultural conditions were normal, reached to maximun after 3 days' incubation which coincided with the maximum utilization of N by fungus mycelliun and then the activity fell down according to the autolysis and pH rising of the culture medium.
