Assessment of Ethanol Fermentation with Rice Bran by Yeasts

米糠배지에서 酵母에 의한 에탄올 발효액의 평가

Rice bran was employed as a main medium component for ethanol fermentation by Saccharomyces species. Among the several strains of .Saccharomyces yeasts. S. cerevisiae IF0 2346 was selected as the hest strain in view of the interest in the production of ethanol and amino acids. It was found that S. cerevisiae IF0 2346 showed $3\times 10^8$cells/d and 4.7% (v/v) ethanol production after 72 hr cultivation. Although total amount of free amino acids was decreased from 1.099 mg/l to 829 mg/l during the fermentation, glutamic acid. histidine, and isoleucine were increased considerably. With the supplement of 5% glucose to the ferrnentation medium, both ethanol and amino acid production were increased up to 134% and 264%, respectively. compared to the control case. Glutamic. acid, leucine, alanine. phenylalanint:, and valine were the major amino acids in the fermentation broth.

Saccharomyces속 효모를 사용하여 미강을 배지로 하여 에탄올을 발효특성을 조사하였다. 액화효소와 당화효소를 전처리한 미강에서 여러 Saccharomyces속 효모들을 배양한 결과 Saccharomyces cerevisiae IFO 2346이 높은 에탄올 생성 및 유리아미노산 함량을 나타내었다. 균체성장은 발효 24시간에 $3\times 10^8$cell/ml로 증가하였으며, 발효 72시간후 4.7의 에탄올을 생성하였다. 유리아미노산 총량은 발효과정중 1,099mg/l에서 829mg/l로 감소하였으나, glutamic acid, histidine 및 isoleucine은 오히려 각각 218%, 31%5 및 1%48로 증가하였다.