摘要
化石能源的大量使用导致了严重的环境问题。无污染的可再生能源如太阳能、风能、生物质能的使用有望缓解能源与环境的矛盾。其中，生物质能源被认为是最具潜力的可再生能源之一。微生物燃料电池（MFC）是一种可以将有机物直接高效转化为电能的新技术。MFC能够将生物质直接转化为电能，应用潜力巨大。但是，目前MFC转化生物质效率低下，主要限制性因素之一是MFC 难以高效将生物质来源木糖高效转化为能源产品。
针对这一关键性限制因素，本研究通过菌株筛选，获得了一株能够以木糖为唯一底物产电的新型产电菌，并建立了高效木糖MFC。进一步，发现该MFC 利用木糖产电的同时能够产氢，实现了木糖同时转化为生物氢和生物电，为木糖的高效能源化转化提供了新的路径。主要研究内容及结果如下：筛选获得了以木糖为唯一电子供体的新型产电微生物。然后，分离并鉴定了一种新的产电酵母菌株（Cystobasidium slooffiae菌株JSUX1），该菌株可以通过使用木糖作为唯一碳和能源在MFC中发电。该菌株能够产生显著的电流密度，并具有快速代谢木糖的能力。进一步研究发现，该菌株在厌氧培养条件下或在MFC中可以利用木糖产生生物氢气。因此，利用此菌株构建了能够利用木糖同时产电和产氢的新型微生物燃料电池。该电池利用木糖可以获得的输出功率为67 mW/m2、生物氢气为23 L/m3。此外，通过电化学分析表明该菌株主要以细胞分泌的核黄素作为电子中介体进行细胞与电极间的电子传递。
什么是帕金森综合症
为了提高木糖MFC的性能，本研究开发了聚苯胺(PANI)电极修饰策略。通过SEM、FTIR、拉曼和XRD对PANI修饰电极进行分析，证实了PANI成功修饰到电极表面。拉曼位移峰显示最强的峰出现在C=N的 1487 cm−1伸缩区，该区是电荷势的函数，而位于1586 cm−1的波段对应的是作为氧化剂的C=C醌型环。此外，FTIR分析显示C−C链在1558 cm−1、1521 cm−1、1488 cm−1处有条带，在1295 cm−1、1241 cm−1、1123 cm−1处出现了C−O环的伸长。另外，XRD 图谱显示在25度和20度角范围内最高的结晶度，这与结构环中存在的胺基和
III
酚基相容。针对PANI修饰对MFC性能影响的研究结果表明，在同等条件下（相同电极面积、相同菌浓度和相同木糖浓度），PANI修饰使木糖MFC的产电功率提高到大约119 mW/m2，生物氢产量增加到37.3 L/m3。另外，对不同木糖MFC放电后的电极生物膜进行了比较分析。研究发现，PANI修饰使电极表面负载的生物量大幅提高。最后通过系列分析表明，生物膜细胞量的增加是PANI 电极修饰强化木糖MFC性能主要机制。
进一步，建立了利用氧化石墨烯（GO）修饰电极提高木糖MFC性能的策略。研究发现，GO在酵母菌菌株JSUX1的作用下被生物还原成还原性石墨烯(rGO)，并在电极表面形成了3D rGO水凝胶。我们对GO和rGO进行了表征。XRD图谱显示在反射平面（001）处具有纯GO的峰，而生物产生的rGO在（0
02）和（110）的反射平面处显示峰。此外，通过FTIR和拉曼分析证实了酵母细胞将GO还原为rGO。研究结果表明，利用GO修饰电极可以使木糖MFC 的生物电输出功率增加到约150 mW/m2，生物氢产量增加到48 L/m3。通过进一步的电化学分析表明，电子介体（核黄素）介导的电子转移效率增高，电池与电极之间的电子转移电阻大大降低是GO电极修饰增强木糖MFC性能的主要机制。
综上，本研究分离获得了一株可以利用木糖同时产电和产氢的产电真核微生物, 并开发了一种用于同时产氢和产电的高效木糖MFC，为生物质能源利用提供了新的思路和方法。
关键字：微生物燃料电池, 木糖, 生物制氢, 酵母, 生物电，聚苯胺，氧化石墨烯。
IV
Abstract
A wide range using of fossil fuels has caud major environmental challenges. Therefore, environmental-friendly renewable energy resources such as solar energy, wind energy, and biomass energy have been considered to facilitate sustainable energy development and environmental challenges. Among them, biomass energy has been regarded to be one of the renewable energy resources with high capability. Thus, microbial fuel cell (MFC) is a new technology that can directly a
nd efficiently convert organic compounds into electrical energy, which holds extensive applications. Although now, MFC efficiency from biomass conversion is low, in which one of the main limiting factors is faced with the difficulty of MFC for efficiently converting biomass-derived xylo into energy products. According to this key limiting factor, strain screening method was assayed to isolate a new type of exoelectrogenic strain that can generate electricity using xylo as a sole carbon source with efficient utilization of xylo in MFC. Further, it was found that the MFC can produce hydrogen while xylo is ud to generate electricity, and it can enable simultaneous conversion of xylo into biohydrogen and bioelectricity production, which provides a new pathway and potential for the efficient energy harvesting from xylo. The main rearch contents and results are as follows;
Strain screening method was aimed to achieve a new type of exoelectrogenic microorganism for xylo-fueled MFC. In order, we isolated and identified a new exoelectrogenic yeast strain (Cystobasidium slooffiae strain JSUX1) that can generate bioelectricity using xylo as a sole carbon and energy source in MFC. After adaptation, it produced significant current density with rapid xylo metabolism. More surprisingly, the isolated strain produced biohydrogen either in anaerobic flask incubation or in MFC, which delivered 67 mW/m2power output and 23 L/m3 biohydrogen in MF脾土
C. Further, the electrochemical analysis indicated that riboflavin was creted by strain JSUX1 as an electron mediator for efficient electron transfer between cells and electrode in MFC. Next, electrode modification methods were developed to improve the performance of xylo-fueled MFC. We ud polyaniline (PANI) polymers to modify carbon felt (CF), and carbon cloth (CC) electrodes surface. The PANI-modified electrode was characterized by SEM, FTIR, Raman, and XRD analysis. Raman shift peaks showed the most inten peaks in the stretching
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region of 1487 cm−1assigned to C=N as a function of charge potential, and the located band on 1586 cm−1 corresponds to C=C quinoid ring as an oxidizing agent. Further, FTIR analysis detected the bands at 1558 cm−1, 1521 cm−1, 1488 cm−1 that were corresponded to C−C chain, and 1295 cm−1, 1241 cm−1, 1123 cm−1 were referred to C−O ring stretching. Besides, XRD pattern showed the highest degree of crystallinity in the domain of 25 and 20 angle degrees, which were compatible with amine and phenolic groups prented in the structural ring. The effect of PANI modification on MFC performance revealed an enhancement on bioelectricity about 119 mW/m2 and biohydrogen production about 37.3 L/m3. Further, biofilm analysis indicated that PANI modification can highly enhance the cell loading on the electrode surface, which resulted in MFC performance. Moreover, w
e ud graphene oxide (GO) for electrodes surface modification to further improve the MFC performance. Interestingly, GO was biologically reduced to rGO by yeast cell strain JSUX1 and formed a 3D-rGO hydrogel on the surface of the electrodes. The characterization of GO and rGO with XRD pattern showed a peak with pure GO at the reflection plane of (001), while the biologically produced rGO showed peaks at reflection planes of (002) and (110). Further, the reduction of GO to rGO by yeast strain was confirmed by FTIR and Raman analysis. The effect of GO modification on MFC performance revealed an enhancement on bioelectricity about 150 mW/m2and biohydrogen production about 48 L/m3. Moreover, the electrochemical analysis indicated that EET of MET for riboflavin was enhanced and the charge transfer resistance between cells and electrodes was largely decread, which was the underlying mechanism for performance improvement by GO modification.
In summary, this work isolated a new exoelectrogenic eukaryotic microorganism that can simultaneously produce biohydrogen and bioelectricity from xylo, and it could develop an efficient xylo-fueled MFC for biohydrogen and bioelectricity production, which would diversify the toolbox of biomass energy.
Keywords:Microbial fuel cell, Xylo, Biohydrogen, Yeast, Bioelectricity, Polyaniline, Graphene oxide.
VI
Table of Contents
Acknowledgments ........................................................................................................ I 摘要 ............................................................................................................................ III Abstract ........................................................................................................................ V Table of Contents ..................................................................................................... V II List of Abbreviations ................................................................................................ XI List of Symbols ....................................................................................................... XIII List of Figures ..........................................................................................................XIV List of Tables ....................................................................................................... XVIII Chapter 1: General introduction .. (1)
1.1 Renewable energy (1)
1.2 Overview of microbial fuel cell (MFC) (1)
雷锋的故事简介1.3 MFC applications and advantages (2)
九年级语文作文
酒的作文
1.3.1 Wastewater treatment (3)
1.3.2 Biological production of hydrogen (4)
1.3.3 Batteries for bionsing (4)
1.4 Biological aspect of MFC (5)
1.4.1 Electroactive microorganisms (EAMs) (5)
1.4.2 Biofilm formation (7)
1.4.3 Electron transfer mechanism (7)
1.5 Physical aspect of MFC (8)
亚琛大学鲫鱼汤怎么做好喝1.5.1 Substrates ud for MFC (8)
1.5.1.1 Xylo a derived by-product from biomass (10)
1.5.1.2 Organic/Substrate loading rate (OLR) (11)
米亚罗毕棚沟
1.5.2 Temperature (12)
1.5.3 pH (13)
1.6 MFC configuration and materials (13)
1.6.1 Reactor configuration (13)
1.6.2 Separator (14)
1.6.3 External Resistance (14)
1.6.4 Electrode materials and modification (14)
VII
