지원사업
학술연구/단체지원/교육 등 연구자 활동을 지속하도록 DBpia가 지원하고 있어요.
커뮤니티
연구자들이 자신의 연구와 전문성을 널리 알리고, 새로운 협력의 기회를 만들 수 있는 네트워킹 공간이에요.
논문 기본 정보
- 자료유형
- 학위논문
- 저자정보
- 지도교수
- 박중곤
- 발행연도
- 2013
- 저작권
- 경북대학교 논문은 저작권에 의해 보호받습니다.
이용수11
이 논문의 연구 히스토리 (2)
- 이 논문의 후속연구가 궁금하신가요?
- 연관 학술논문 또는 학술발표를 통해 보다 발전된 연구결과를 확인하실 수 있습니다.
- 이 논문의 연구 히스토리 확인하기
초록· 키워드
오류제보하기
Bio-ethanol is an alternative and renewable energy source produced through the fermentation of sugars by certain microorganisms specifically yeast. However, the relatively high production cost of bio-ethanol remains a major hurdle in its globalization. The search of cheap raw sources is therefore a burning topic at present to resolve the dilemma. Among waste sources, the waste from beer fermentation broth (WBFB) has been found an excellent and inexpensive resource for bioethanol production. Analysis of the WBFB revealed the presence of high amounts of carbon, nitrogen, malt derived hydrolyzing enzymes and yeast cells. These unique features of WBFB can be used for ethanol production via simultaneous saccharification and fermentation (SSF) without the addition of saccharification enzymes, microbial cells or carbohydrates. Presently 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 by adding the yeast cells (from WBFB) to the starch solution and analyzing the produced glucose. By varying the temperature between (30, 40, 50, 60 and 70°C), it was found that the saccharification capabilities increased with increase in temperature and highest glucose was produced at 60°C and 70°C after 4h. The saccharifying capacities of WBFB were merely devoted to the hydrolyzing enzymes present in WBFB. Although the CFU was reduced at elevated temperature however, the yeast cells were found capable to survive at high temperature for short time period of 4h.
The fermentation potentials of WBFB were evaluated using two yeast strains (Saccharomyces cerevisiae and Kluyveromyces fragilis) and compared with chemically defined media (CDM) used as control. 3.7% and 5.5% ethanol was produced from CDM with addition of S. cerevisiae and K. fragilis, respectively after 20 h. Using same experimental conditions with WBFB resulted in 1.3% and 1.2% ethanol for both yeast species, respectively. Although the bioethanol obtained from WBFB was relatively lower, but still the quantity is reasonable as it is obtained without addition of nutrients and sugar sources to the WBFB. The CFU of both strains increased at 30 and 40°C however, it reduced significantly at further higher temperature of 50 and 60°C. The microscopic picture revealed that the morphology of both yeast strains was damaged at higher temperatures when kept for long times. Ethanol production from a mixture of WBFB and CDM without addition of any microbial species confirmed the fermentation capabilities of WBFB. The microbial species from WBFB were able to produce 1.3% ethanol from WBFB and CDM mix solution. This further proves the effectiveness of WBFB utilization for fermentation with other media.
The experiments for simultaneous saccharification and fermentation were performed using WBFB, starch solution and CDM as cultured media. The saccharifying enzymes and the yeast cells present in WBFB were the only factors conducting both steps without any additional enzymes or microbial cells. Conducting the experiments at various temperatures of 30, 40, 50 and 60°C revealed the highest yields for glucose at 50 and 60°C and maximum ethanol at 30°C. However the 40°C could be considered the optimum temperature for obtaining both the products simultaneously. With the addition of Saccharomyces cerevisea and Kluyveromyces fragilis to the culture media consisting of WBFB and starch solution, the process of SSF was found to become much efficient.
The overall result of the present work revealed that WBFB is a rich source of saccharifying enzymes and yeast cells. It has the potential of conducting the saccharification, fermentation and SSF by itself and can be proved much effective when utilized in combination with other saccharifying and fermenting substrates. Our present work can broaden the future prospective of WBFB as a sole feedstock for bioethanol production owing to its excellent saccharifying and fermentation potentials.
The saccharification potentials of the WBFB were evaluated by adding the yeast cells (from WBFB) to the starch solution and analyzing the produced glucose. By varying the temperature between (30, 40, 50, 60 and 70°C), it was found that the saccharification capabilities increased with increase in temperature and highest glucose was produced at 60°C and 70°C after 4h. The saccharifying capacities of WBFB were merely devoted to the hydrolyzing enzymes present in WBFB. Although the CFU was reduced at elevated temperature however, the yeast cells were found capable to survive at high temperature for short time period of 4h.
The fermentation potentials of WBFB were evaluated using two yeast strains (Saccharomyces cerevisiae and Kluyveromyces fragilis) and compared with chemically defined media (CDM) used as control. 3.7% and 5.5% ethanol was produced from CDM with addition of S. cerevisiae and K. fragilis, respectively after 20 h. Using same experimental conditions with WBFB resulted in 1.3% and 1.2% ethanol for both yeast species, respectively. Although the bioethanol obtained from WBFB was relatively lower, but still the quantity is reasonable as it is obtained without addition of nutrients and sugar sources to the WBFB. The CFU of both strains increased at 30 and 40°C however, it reduced significantly at further higher temperature of 50 and 60°C. The microscopic picture revealed that the morphology of both yeast strains was damaged at higher temperatures when kept for long times. Ethanol production from a mixture of WBFB and CDM without addition of any microbial species confirmed the fermentation capabilities of WBFB. The microbial species from WBFB were able to produce 1.3% ethanol from WBFB and CDM mix solution. This further proves the effectiveness of WBFB utilization for fermentation with other media.
The experiments for simultaneous saccharification and fermentation were performed using WBFB, starch solution and CDM as cultured media. The saccharifying enzymes and the yeast cells present in WBFB were the only factors conducting both steps without any additional enzymes or microbial cells. Conducting the experiments at various temperatures of 30, 40, 50 and 60°C revealed the highest yields for glucose at 50 and 60°C and maximum ethanol at 30°C. However the 40°C could be considered the optimum temperature for obtaining both the products simultaneously. With the addition of Saccharomyces cerevisea and Kluyveromyces fragilis to the culture media consisting of WBFB and starch solution, the process of SSF was found to become much efficient.
The overall result of the present work revealed that WBFB is a rich source of saccharifying enzymes and yeast cells. It has the potential of conducting the saccharification, fermentation and SSF by itself and can be proved much effective when utilized in combination with other saccharifying and fermenting substrates. Our present work can broaden the future prospective of WBFB as a sole feedstock for bioethanol production owing to its excellent saccharifying and fermentation potentials.
목차
Ⅰ. 서론1.1. 연구 배경 ··················································································11.2. 연구 목적 ··················································································5Ⅱ. 재료 및 방법2.1. 맥주 폐 효모액 ········································································72.2. 사용 균주 ··················································································72.2.1. Saccharomyces cerivisiae ··············································72.2.2. Kluyveromyces fragilis ·····················································82.3. 배지 조성 ·················································································112.4. 실험 방법 ·················································································132.4.1. 당화능 측정 ··········································································132.4.2. 발효능 측정 ··········································································132.4.2.1. 발효능 control system ···················································132.4.2.2. 맥주 폐 효모액의 발효능 측정 ·······································142.4.2.3. Chemically defined media를 이용한 발효능 측정 ···142.4.3. 동시당화발효능 측정 ··························································142.5 분석 ····························································································152.5.1. Glcuose 농도 측정 ·····························································152.5.2. Ethanol 농도 측정 ·······························································162.5.3. CFU 측정 ··············································································162.5.4. Dry cell weight 측정 ··························································17Ⅲ. 실험 결과 및 고찰3.1. 맥주 폐 효모액의 당화능 ·······················································183.2. 맥주 폐 효모액의 발효능 control system ··························213.3.1. Saccharomyces cerivisiae를 이용한 control system ·············································································································213.3.2. Kluyveromyces fragilis를 이용한 control system ············································································································253.3.3. Yeast cell 종류에 따른 control system에서ethanol 생산량 비교 ·····························································································283.3. 맥주 폐 효모액의 발효능 ······················································303.3.1. Chemically defined media 추가 ····································303.3.2. Yeast cell 추가 ·································································343.3.2.1. Saccharomyces cerivisiae 추가 ·······························343.3.2.2. Kluyveromyces fragilis 추가 ·······································373.3.2.3. Yeast cell 종류에 따른 맥주 폐 효모액에서의 ethanol 생산량 비교 ·····························································································403.3.3. CDM과 Yeast cell 추가 시 맥주 폐 효모액의 발효능 비교 ·····································································································423.4. Chemically defined media와 Yeast cell을 이용한 발효 ············································································································453.4.1. Saccharomyces cerivisiae를 이용한 발효 ··················453.4.2. Kluyveromyces fragilis를 이용한 발효 ·························503.4.3. CDM에 Yeast cell 접종 시 효모 종류에 따른 ethanol 생산량 비교 ·························································································553.5. Yeast cell의 접종 배지로써 CDM과 WBFB의 ethanol 생산량 비교 ·····························································································573.6. 맥주 폐 효모액의 동시당화발효 ··········································583.6.1. Chemically defined media 추가 ····································583.6.2. Glucose를 제거한 Chemically defined media 추가 ···········································································································623.6.3. Glucose를 포함한 CDM과 제거한 CDM 추가 시 동시당 화발효 비교 ····················································································663.6.4. Yeast cell 추가 ··································································673.6.4.1. Saccharomyces cerivisiae 추가 ·······························673.6.4.2. Kluyveromyces fragilis 추가 ······································703.6.4.3. Yeast cell 종류에 따른 동시당화발효과정 비교 ·······733.6.5. WBFB를 비롯한 폐기물을 이용한 바이오에탄올 생산 비교 ······································································································74Ⅳ. 결론 ···························································································77참고문헌 ··························································································80
최근 본 자료
댓글(0)
0