맥주 폐 효모액(waste from beer fermentation broth, WBFB)은 바이오 에탄올 생산을 위한 우수하고 저렴한 원료이다. 본 연구에서는 바이오 에탄올 생산을 위해 WBFB의 당화능과 발효능을 확인하는 실험을 진행하였다. 당화능은 온도를 30, 40, 50, 60, $70^{circ}C$로 다르게 하여 실험했는데 온도가 올라감에 따라 당화능은 증가하였고 4시간 후 $60^{circ}C$와 $70^{circ}C$에서 많은 양의 glucose가 생산되었다. WBFB와 chemically defined media (CDM) 혼합물에서는 어떠한 미생물의 첨가 없이도 발효가 되어 에탄올이 생산되었다. 동시당화발효능을 30, 40, 50, $60^{circ}C$의 다양한 온도에서 실험해본 결과 $30^{circ}C$에서 에탄올이 가장 많이 생산되었다. 또 이 실험은 WBFB, starch 용액 그리고 CDM을 이용하여 수행하였는데 WBFB에 있는 당화 효소와 효모가 어떠한 추가적 미생물 첨가 없이 당화와 발효를 가능케 하는 요인이었다.
The waste from beer fermentation broth (WBFB) has been found an excellent and inexpensive resource for bioethanol production. We tried to evaluate the saccharification and fermentation capabilities of WBFB to confirm its effectiveness for bioethanol production. The saccharification potentials of the WBFB were evaluated at various temperatures (30, 40, 50, 60 and $70^{circ}C$). It was found that the saccharification capabilities increased with temperature and highest reached maximum at $60^{circ}C$ and $70^{circ}C$ after 4h. Ethanol production from a mixture of WBFB and chemically defined media (CDM) without addition of any microbial species confirmed the fermentation capabilities of WBFB. Simultaneous saccharification and fermentation were performed using WBFB, starch solution and CDM as culturing media. The maximum yield of bioethanol production was obtained at $30^{circ}C$. The saccharifying enzymes and the yeast cells present in WBFB were essential factors for the production of bioethanol from WBFB without any additional enzymes or microbial cells.
