Cholesterol로부터 미생물전환 방법에 의한 4-androstene-3,17-dione(AD)의 생성에 대해 연구를 수행했다. 발효액중에 cholesterol의 용해도를 증가시키기 위해 ethanol을 용매로 사용하였는데, ethanol 농도가 2%(v/v)까지는 세균성장이 크게 저해되지 않았다. 미생물전환은 pH를 7.0으로 조절하고, 초기대수 증식기에 cholesterol을 첨가했을 때 효율적으로 AD가 생성되었다. AD 생성을 높이기 위해 cholesterol 첨가방법을 여러 가지로 변환시켰다. 즉, 최종 cholesterol 농도를 0.1% 하여 ethanol에 녹여 간헐적으로 첨가했을 때 가장 높은 수율을 얻었다. Cholesterol을 세번(전체 3g/$ell$) 첨가했을 때 최종 전환수율이 65%에 도달한 반면, 같은 양의 cholesterol (3g/$ell$)을 한번에 넣었을 때 40%의 생성수율을 얻었다.
Production of 4-androstene-3,17-dione(AD) from cholesterol by microbial conversion was investigated. To facilitate the solubilization of cholesterol in the fermentation broth, ethanol was used as an organic solvent. Inhibition on cell growth by ethanol was observed to be negligible upto 2% (V/V) concentration. Microbial conversion was successfully carried out with high yield when the cholesterol was added at early logarithmic growth phase with pH control at 7.0. In order to improve the process productivity, bioconversion was conducted at various mode of cholesterol addition ; 0.1% (V/W) of cholesterol was found to be most appropriate for solubilization in ethanol and was added intermittently. When added three time(total 3 g/$ell$), overall bioconversion yield reached upto 65% while single addition of same amount of cholesterol (3 g/$ell$) yielded about 40% conversion.
