Abstract
Five strains producing ethanol were isolated from soil near traditional alcohol production factory in Gwangju, Korea. One of the isolated strains maintained relatively stable ethanol production in shaking culture. The isolated strain KJ was proved to be Saccharomyces italicus, based on several biochemical and morphological tests containing assimilation of carbon compounds. In investment of the most suitable carbon for ethanol production, ethanol concentration of 5.46 g/L and yield of 0.53 g-ethanol/g-glucose were obtained in condition of glucose 10 g/L in YM medium. Experimental optimal conditions for ethanol fermentation by S. italicus KJ were as follows; temperature $30^{\circ}C$, initial pH 5.0, initial concentration 10% of glucose, anaerobic condition in the liquid cultivation. When enzymatically saccharified food wastes(SFW) were used as the production medium, ethanol production yield was 0.57 g-ethanol/g-reducing sugar. Therefore, SFW will contribute to lower the production cost of ethanol for industrial application.
주정공장 근처 토양에서 분리한 에탄올 발효균주 KJ는 Saccharomyces italicus로 판명되었으며, glucose가 최적의 탄소원으로 확인되었다. 균주 KJ의 최적배양조건은 온도 $30^{\circ}C$, 초기 당 농도 10%, 초기 pH 5 근방, 혐기조건으로 판명되었다. 초기 탄소원이 동일한 조건에서 YM배지(glucose 10 g/L)와 SFW배지(RS 10 g/L)에서 에탄올 생산은 각각 5.34, 5.68 g/L로 나타나, KJ균주는 음식물쓰레기 당화액을 에탄올 발효배지로 적절하게 사용될 수 있음이 확인되었다. 에탄올 생산배양에 SFW의 이용은 에탄올생산단가를 대폭 낮추게 하여 대체에너지인 에탄올의 대량생산기술의 경제성을 확보하는데 크게 기여할 것이다.