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dc.contributor.advisor조경숙-
dc.contributor.author이윤영-
dc.creator이윤영-
dc.date.accessioned2016-08-26T04:08:41Z-
dc.date.available2016-08-26T04:08:41Z-
dc.date.issued2015-
dc.identifier.otherOAK-000000116015-
dc.identifier.urihttp://dspace.ewha.ac.kr/handle/2015.oak/213312-
dc.identifier.urihttp://dcollection.ewha.ac.kr/jsp/common/DcLoOrgPer.jsp?sItemId=000000116015-
dc.description.abstract최근 화석연료의 고갈과 기후변화 문제를 해결하기 위해 바이오매스로부터 대체 에너지를 회수하는 방법에 대한 연구가 활발히 진행되고 있다. 그 중 미생물연료전지 (MFC)는 유기성 폐수를 처리함과 동시에 이용이 용이한 전기 에너지를 생산하는 것에 가장 큰 장점이 있다. MFC는 다양한 종류의 유기성 폐수를 처리할 수 있으며, 고농도의 유기성 폐수 역시 기질로 이용할 수 있다. 본 연구에서는 실험실 규모에서 세 종류의 MFC를 개발하여, 인공 기질 및 고농도의 당밀 폐수처리를 주입하여 전기 에너지 생성과 유기물 제거를 평가하였다. 또한 생촉매를 이용하여 MFC의 성능 개선을 평가하고, 미생물학적 특성을 조사하였다. AC-MFC를 이용하여 PEM 여부에 따른 에너지 생산 및 미생물 군집구조를 평가하였다. 최대 전력 밀도 및 쿨롱효율은 PEM 유무에 따라 큰 차이를 나타내지 않았으나, 최대 전압 생산과 COD 제거량은 PEM이 존재하지 않을 때 더 큰 효율을 보였다. 또한 PEM이 존재하지 않을 때 미생물 군집의 다양성이 더 높았다. 이를 통해 PEM이 존재하지 않는 AC-MFC가 전력 생산, COD 제거, 미생물의 성장에 더 효과적임을 확인하였다. 당밀폐수를 효과적으로 처리하기 위해, 세 가지 유형의 MFC를 대상으로 전기 생산량, COD 제거율, 미생물 군집구조를 비교 및 평가하였다. PEM이 없는 단일형 AC-MFC, PEM이 존재하는 단일형 ACM-MFC, 2개의 챔버로 구성된 평판형 H-MFC를 이용하였고, 10,000 mg•L-1 COD의 당밀폐수를 연속 주입하였다. 두 유형의 단일형 MFC에서는 COD 제거율과 미생물 군집구조가 유의한 차이를 나타나지 않았으며, 이는 PEM이 MFC 효율에 영향을 끼치지 않는 것을 의미한다. 그러나 단일형 MFC의 COD 제거율은 H-MFC보다 유의하게 높았으며, 전기생산량은 H-MFC가 단일형 MFC의 1.4-2.2배 높은 효율을 보였다. 미생물 군집 구조 역시 MFC 구조에 따라 차이를 나타냈으며, 본 연구를 통해 PEM의 유무보다 MFC 반응조의 구조가 유기성 폐수의 처리 및 에너지 생산에 더 큰 영향을 끼치는 것을 알 수 있었다. 당밀폐수의 효과적인 처리 공정을 평가하기 위해 BioCH4-MFC 및 BioH2-MFC 통합 공정을 설계하여, MFC의 전기화학적 특성 및 미생물 군집 구조를 조사하였다. 당밀 폐수를 처리한 BioCH4 및 BioH2 반응조의 유출수를 기질로하여, MFC에 각각 연속 주입하였으며, 두 MFC 모두 HRT를 3일로 하였을 때, 가장 높은 전기화학적 효율을 보였다. 두 MFC 간에 Eubacterial 군집 구조는 유의한 차이를 나타내지 않았으나, archaeal 군집은 차이를 나타냈다. BioCH4-MFC 및 BioH2-MFC 통합 공정을 통해 당밀폐수로부터의 에너지를 회수 및 COD 제거 가능성을 확인하였다. MFC 바이오필름에서 Candida sp. IR11과 Klebsiella sp. IR21을 분리 및 동정하여, MFC 내 전기 생산 여부와 생촉매로의 가능성을 살펴보았다. Strain IR11와 IR21 모두 외부 매개체의 도움 없이 전기 에너지를 생산할 수 있었으며, 유기성 폐수를 주입한 MFC의 전기화학적 효율도 향상시켰다. 이를 통해 본 연구에서 분리 및 동정한 두 종의 미생물이 MFC 내에서 생촉매로 이용가능함을 알 수 있었다.;Owing to the shortage of fossil fuels and climate change, research on the recovery of renewable energy from biomass has been extensively conducted. Microbial fuel cells (MFCs) have the great advantage of being suitable for organic wastewater treatment and electricity generation that can be directly harnessed by humans. MFCs can treat various types of organic wastewaters, and they can also use high strength organic wastewater as a substrate in particular. In this study, we designed three types of MFCs at a lab scale, and their electric energy generation and organic removal rates were evaluated using artificial substrate and high strength molasses wastewaters. In addition, the enhancement of MFC performance by biocatalysts and bacterial community structures was investigated. The effects of proton exchange membranes (PEMs) on the performance and bacterial community of air-cathode MFCs (AC-MFCs) were investigated. PEM did not affect the maximum power density and coulombic efficiency. However, PEM use adversely affected maximum voltage production and the rate of organic compound removal (p<0.05). In addition, the MFCs had a greater bacterial population and diversity index when PEM was absent (p<0.05). MFC systems without PEM are more efficient with respect to power production and COD removal as well as exoelectrogen growth. Electrochemical characteristics and bacterial communities were compared in 3 types of MFCs used for treating molasses wastewater (10,000 mg•L-1 COD). Single-chamber MFCs without and with a PEM, and two-chamber H-MFCs were constructed. The COD removal, electricity generation, and bacterial communities in the two types of single-chamber MFCs were similar, indicating that the PEM did not enhance the reactor performance. However, the COD removal in the single-chamber MFCs was higher than in the H-MFC, and electricity generation in the H-MFC was higher than in the single-chamber MFCs. The bacterial community structures in the MFCs with different numbers of chambers were also distinguishable. To evaluate the efficiency of molasses wastewater treatment, MFC performances were investigated using BioCH4-MFC and BioH2-MFC integrating systems. The MFC systems were fed with rejected wastewater from BioCH4 or BioH2 reactors treating molasses wastewater in a continuous flow mode. Both MFC systems showed maximum efficiency of electricity production at HRT of 3 d. There was no significant difference in the eubacterial community structure between both MFC systems, but the archaeal community structure showed a significant difference. The results demonstrate that the introduction of MFC after the BioCH4 or BioH2 process has advantages for energy recovery as well as COD removal from molasses wastewater. Novel Candida sp. IR11 and Klebsiella sp. IR21 were isolated from an anodic biofilm in the MFC reactors. Electricity production and the biocatalyst potential of strains IR11 and IR21 were evaluated. Strains IR11 and IR21 produced electrical energy without any artificial mediators, and they improved the performance of conventional MFCs fed with organic wastewaters. These results indicated that Candida sp. IR11 and Klebsiella sp. IR21 are promising biocatalysts for the enhancement of MFC performance.-
dc.description.tableofcontentsI. Introduction 1 A. Literature review of MFCs 1 B. The objectives of this study 5 II. Effects of proton exchange membrane on the performance and bacterial community composition of air-cathode microbial fuel cells 9 A. Introduction 9 B. Materials and Methods 11 1. MFC construction 11 2. MFC operation 14 3. Electrochemical performance analysis 14 4. Bacterial community analysis 16 a. Anodic biofilm sampling and DNA extraction 16 b. Quantitative droplet digital PCR (ddPCR) 16 c. PCR and pyrosequencing 17 d. Data analysis for bacterial community 18 e. Extended local similarity analysis (eLSA) 19 C. Results 19 1. MFC performance 19 2. Quantitative comparison of total bacteria and Geobacter spp. 25 3. Bacterial community structure of anodic biofilm 28 4. Extended local similarity analysis (eLSA) 34 D. Discussion 36 III. Characterization of the COD removal, electricity generation, and bacterial community in microbial fuel cells treating molasses wastewater 43 A. Introduction 43 B. Materials and Methods 47 1. Molasses wastewater 47 2. MFC construction 47 3. Inoculation source and set-up 50 4. MFC operation using molasses wastewater 51 5. Bacterial community analysis 52 a. Anodic biofilm sampling, RNA extraction, and cDNA synthesis 52 b. PCR and ion torrent sequencing 54 c. Data analysis of the eubacterial and archaea6 communities 56 C. Results 57 1. Electrochemical characteristics of the MFC structures 57 2. Euacterial community structure of the anodic biofilm 63 3. Archaeal community structure of the anodic biofilm 66 D. Discussion 68 IV. Performances of microbial fuel cells fed with rejected wastewater from Biomethane and Biohydrogen producing process treating molasses wastewater 78 A. Introduction 78 B. Materials and Methods 81 1. Rejected wastewater 81 2. MFC construction 82 3. Acclimation of MFC systems 82 4. Operation of MFCs with rejected wastewater from BioCH4 or BioH2 producing process 83 5. Bacterial community analysis 84 C. Results 87 1. Comparison of electrochemical characteristics 87 2. Comparison of the eubacterial community structure of the anodic biofilm 95 3. Comparison of the archaeal community structure of the anodic biofilm 98 D. Discussion 100 V. Isolation and characterization of a novel electricity-producing yeast, Candida sp. IR11 104 A. Introduction 104 B. Materials and Methods 108 1. Isolation and identification of strain IR11 108 2. Reduction of ferric iron by strain IR11 110 3. Electricity production by strain IR11 and its dynamics in an MFC reactor 111 a. MFC reactor construction and operation 111 b. Quantification of strain IR11 through Quantitative Real-Time PCR (qRT-PCR) 112 4. Inoculation effect of strain IR11 in a conventional MFC reactor 114 a. Electricity production and COD removal 114 b. Comparison of Candida sp. abundance by qRT-PCR 116 c. Comparison of bacterial community 117 C. Results and Discussion 119 1. Identification of strain IR11 129 2. Ferric iron reduction by strain IR11 122 3. Electrical performance by strain IR11 in an MFC reactor 124 4. Enhancement of electrochemical performance by the inoculation of strain IR11 130 5. Comparison of eubacterial and archaeal communities on the anodic biofilms 138 VI. Enhancement of electricity production in mediatorless air-cathode microbial fuel cell using Klebsiella sp. IR21 146 A. Introduction 146 B. Materials and Methods 152 1. Isolation and identification of strain IR21 152 2. Reduction of ferric iron by strain IR21 154 3. Electricity production by strain IR21 and its dynamics in an MFC reactor 155 a. MFC reactor construction and operation 155 b. Quantification of strain IR21 through Quantitative Real-Time PCR (qRT-PCR) 156 4. Inoculation effect of strain IR21 in a conventional MFC reactor 158 a. Electricity production and COD removal 158 b. Comparison of Klebsiella sp. abundance by qRT-PCR 161 C. Results and Discussion 161 1. Identification of strain IR21 161 2. Ferric iron reduction by strain IR21 163 3. Electrical performance by strain IR21 in an MFC reactor 167 4. Enhancement of electrochemical performance by the inoculation of strain IR21 172 VII. Conclusions 181 Reference 185 Abstract (in Korean) 206-
dc.formatapplication/pdf-
dc.format.extent2935832 bytes-
dc.languageeng-
dc.publisher이화여자대학교 대학원-
dc.subject.ddc600-
dc.titleEvaluation of electrochemical performance in microbial fuel cells (MFCs) treating molasses wastewater and its enhancement-
dc.typeMaster's Thesis-
dc.creator.othernameLee, Yun-Yeong-
dc.format.pagexv, 208 p.-
dc.contributor.examiner조경숙-
dc.contributor.examiner위대현-
dc.contributor.examiner손아정-
dc.identifier.thesisdegreeMaster-
dc.identifier.major대학원 환경공학과-
dc.date.awarded2015. 8-
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