초록
Asp. usamii shirousamii $U_2$ 균의 국식 배양에 있어서 유기산 및 당화효소생성 조건에 대하여 실험한 결과는 다음과 같다. (1) 유기산 생산은 밀가루 및 밀기울 배지의 경우 $30^{\circ}C$에서 3일간 배양시에 가장 좋았으며 당화효소력은 밀가루 배지의 경우 $35^{\circ}C$, 3일간 배양시에 가장 높았고 밀기울 배지는 $35^{\circ}C$, 2일간 배양시에 거의 최고 역가를 나타냈다. (2) 3일 배양의 경우 배지의 첨수량은 밀가루 배지에서는 60% 첨수일 때, 밀기울 배지에서는 50% 첨수일 때 유기산 생성이 가장 좋았으며 당화효소 생성은 밀가루, 밀기울의 어느 배지에서나 $90{\sim}100%$ 첨수에서 가장 좋았다. (3) 밀가루와 밀기울의 배지를 비교하여 볼 때 유기산의 생성은 밀가루 배지가 좋았으며 당화효소생성은 밀기울 배지에서 높았다. (4) 고구마 전분박과 밀가루를 동량으로 혼합했을 때 밀가루 단일배지보다 유기산 및 당화효소 생성이 높았으며 밀기울에 고구마전분박 첨가의 효과는 없었다. (5) 밀가루, 밀기울 단일배지에 비하여 고구마전분박 단일배지에서는 유기산 및 당화효소 생성이 극히 나빴다. (5) 60% 첨수의 밀가루배지에서 $30^{\circ}C$, 3일간 배양한 경우 생성유기산 중의 약 90%가 구연산이었다.
This experiment was carried out to investigate the producing conditions of organic acid and saccarifing amylase in Koji culture by Asp. usamii shirousamii $U_2$. The results were as follows. 1. When the strain $U_2$ was incubated at $30^{\circ}C$, for 3 days in wheat flour and wheat bran media, the organic acid production was maximum. In the case of incubation at $35^{\circ}C$, for 3 days in wheat flour medium and at $35^{\circ}C$, for 2 days in wheat bran medium the activity of saccharifing amylase was highest. 2. When water was added 60% to wheat flour and 50% to wheat bran in the case of 3 days incubation, the organic acid production was superior. Both in wheat flour and wheat bran media, the saccharifing amylase production was most highly, when water was added 90-100%. 3. Comparatively speaking, the organic acid production was better in wheat flour medium than wheat bran medium, but the activity of saccharifing amylase was higher in wheat bran medium. 4. When the sweet potato starch waste and the wheat flour were mixed with same amount, the organic acid and saccharifing amylase production were higher than in simple wheat flour medium. 5. In the medium of sweet potato starch waste the organic acid and saccharifing amylase production were low extremely. 6. In the case of incubation at $30^{\circ}C$, 3 days in wheat flour medium admixed with 60% water, the amount of citric acid in the organic acid formed was about 91%.