전보에서 분리한 균을 사용하여 당밀과 가용성 전분을 발효기질로써 구연산생산에 관한 몇 가지 실험을 한 결과는 다음과 같다. 1) 가용성전분을 기질로 하여 분리균 M-80을 표면배양할 경우 soluble starch 120g, (N $H_4$)$_2$S $O_4$3g, K $H_2$P $O_4$2g, MgS $O_4$.7$H_2O$ 0.2g, F $e^{++}$ 1.5mg, $Zn^{++}$ 1mg, methanol 20m1, D. W. 1ι, initial pH 5.0 으로 하여 8일간 배양하였을 때 61.8mg/ml의 구연산이 생성되었다. 2) 분리균 M-315를 황혈염으로 전처리한 당밀을 기질로 하여 발효조건을 구한 결과, 표면배양은 당밀 250g, N $H_4$N $O_3$0.3g, K $H_2$P $O_4$0.05g, MgS $O_4$.7$H_2O$ 0.01g, methanol 30m1, D. W. 1ι, initial PH 5.0이었고, 액내배양의 경우는 당밀 250g, N $H_4$N $O_3$0.3g, K $H_2$P $O_4$0.1g, MgS $O_4$.7$H_2O$ 0.01g, methanol 30m1, D. W. 1ι, initial pH5.0이었으며 9일 배양으로 각각 69.4mg/ml, 39.6mg/ml의 구연산이 생성되었다.
Some experiments on the citric acid production were carried out from soluble starch and molasses as raw materials. When soluble starch was used as substrate for the fermentation of citric acid by the strain M-80 which had assimilating ability of soluble starch in surface culture, the optimal culture media was 120g of soluble starch, 3.0g of (N $H_4$)$_2$S $O_4$, 2.0g of K $H_2$P $O_4$, 0.2g of MgS $O_4$.7$H_2O$, 1.5mg of F $e^{++}$, 1mg of Z $n^{++}$ and 20ml of methanol were added to 1 liter and optimal pH was 5.5. In about 8 days 61.8mg/ml of citric acid was produced. When treated molasses with potassium ferrocyanide was used as substrate for the fermentation of citric acid by the strain of M-315, the optimal condition in surface culture was 250g of molasses, 0.3g of N $H_4$N $O_3$, 0.05g of K $H_2$P $O_4$, 0.01g of MgS $O_4$.7$H_2O$, 0.5g of Potassium ferrocyanide and 30ml of methanol were added to 1.0 liter. On the other hand, the optimal condition in submersed culture was 250g of molasses, 0.3g of N $H_4$N $O_3$, 0.1g of K $H_2$P $O_4$, 0.01g of MgS $O_4$.7$H_2O$, 0.5g of potassium ferrocyanide, and 30m1 of methanol were added to 1.0 liter and optimal pH was all 5.0. After 9 days culture, 69.4mg/ ml, 39.6mg/ml of citric acid were separately produced in surface and submerged culture media.dia.
