초록
당밀로부터 ethanol을 생산하기 위한 균체순환식 연속발효를 실시하였다. 균주는 Saccharomyces uvarum ATCC 26602를 사용 하였으며 발효온도는 35$^{\circ}C$였다. 발효중 ethanol에 의한 저해를 줄이기 위하여 이단계발효를 시행하였는데, 첫번째 단계에서 공기는 0.12vvm으로 공급하였고 두번째 단계에서는 혐기적상태로 발효를 진행하였다. 당농도를 14%로 희석했을 때 다른 무기물을 추가하지 않아도 ethanol 발효가 진행되었으며 단지 균체증식이 목적일 때는 phosphorus 첨가가 필요하였다. 균체순환식 연속발효로 14%의 당을 함유한 당밀희석액을 발효시키는데 14.5 시간이 소요되었다. 이때의 최종 ethanol 농도는 8.4~9.0%(v/v)로서 ethanol 생산비율은 이론식의 88.1~94.4% 이었다.
A cell-recycled continuous fermentation process was studied to produce ethanol from molasses using Sacchoromyces uvarum ATCC26602 at 35 $^{\circ}C$. The fermentation system was divided into two stages in order to reduce the inhibitions of ethanol and substrate for cell growth and fermentation rate. The first reactor was aerated at the rate of 0.12 vvm whilst the second was kept anaerobic. In medium composition studies, it was revealed that inorganic nutrient supplement to the diluted molasses with 14% fermentable sugar was not needed for the fermentation, however, phosphate limitation was observed when cell propagation was contemplated. By using the cell-recycled continuous fermentation system, 14.5 hour was required to produce 8.4-9.0% (v/v) of ethanol from diluted molasses containing 14% of fermentable sugar. The ethanol productivity was 6.2g/$\ell$hr with the yield of 88.1-94.4% to the theoretical value.