음식폐기물 처리용 혐기성 산 발효조로부터 알코올발효 균주의 분리 및 특성

Isolation and Characterization of An Alcohol Fermentation Strain from Anaerobic Acid Fermentor to Treat Food Wastes

  • Kim, Jung-Kon (Department of Bio Materials Engineering, Chosun University) ;
  • Han, Gui-Hwan (Department of Environmental Engineering, Chosun University) ;
  • Yoo, Jin-Cheol (Department of Pharmacy, Chosun University) ;
  • Seong, Chi-Nam (Department of Biology, Sunchon National University) ;
  • Kim, Seong-Jun (Department of Civil, Geosystem and Environmental Engineering, Chonnam National University) ;
  • Kim, Si-Wouk (Department of Environmental Engineering, Chosun University)
  • 발행 : 2006.12.30

초록

본 실험실에서는 음식폐기물을 효율적으로 소화처리하기위해 Pilot 규모 (10톤)의 3단계 메탄 발효 공정을 개발하여 운전하고 있다. 3단계 메탄발효시스템은 반혐기성 가수분해조, 혐기성 산발효조, 혐기성 메탄발효조로 구성되어 있으며, 이 가운데 두 번째 공정인 혐기성 산발효조로부터 알코올발효능이 우수한 균주 KA4를 분리하였다. 세포의 형태는 타원형 모양이며, 크기는 $5.5-6.5{\times}3.5-4.5\;{\mu}m$ 이었고, 26S rDNA D1/D2 rDNA sequence를 분석한 결과를 바탕으로 Saccharomyces cerevisiae KA4로 명명하였다. 이 균주를 YM 배지에서 배양하였을 경우 $30-35^{\circ}C$에서 최대 생장을 보였으며, 배지내의 초기 에탄올 농도가 5% (v/v)까지는 생장에 영향을 받지 않았으나 그 이상에서는 생장에 저해를 받았고 7% 이상에서는 생장하지 못하였다. 한편 초기 50% (w/v)까지의 당 농도에서는 생장이 가능하였으나 잔류 당 농도를 고려할 때 에탄올 발효를 위한 최적 당 농도는 10%이었다. 이 농도의 당을 이용하여 초기 pH4에서 10까지의 넓은 범위에서 에탄올 발효가 가능하였으며 최적 pH는 6이었다 이 때 에탄올 생산량은 7.4%이었으며, 에탄올 생산수율은 2.87 mol EtOH/mol glucose이었다.

An efficient pilot scale (10 ton) three-stage methane fermentation system to digest food waste has been developed in this laboratory. This system consisted of three stages: semianaerobic hydrolysis, anaerobic acidogenesis and strictly anaerobic methanogenesis. From the secondary acidogenesis reactor, a novel strain KA4 responsible for alcohol fermentation was isolated and characterized. The cell was oval and its dimension was $5.5-6.5{\times}3.5-4.5\;{\mu}m$. This strain was identified as Saccharomyces cerevisiae KA4 by 26S rDNA D1/D2 rDNA sequence. Optimal culture temperature was $30-35^{\circ}C$. Cells were tolerant to 5% (v/v) ethanol concentration, however, were inhibited significantly by higher ethanol concentration up to 7%. The strain could grow well up to 50% (w/v) initial glucose concentration in the YM liquid medium, however, optimal concentration for ethanol fermentation was 10%. It could produce ethanol in a broad initial pH range from 4 to 10, and optimal pH was 6. In this condition, the strain converted 10% glucose to 7.4% ethanol during 24 hr, and ethanol yield was estimated to be 2.87 moi EtOH/mol glucose.

키워드

참고문헌

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