产电微生物及微生物燃料电池最新研究进展

新型产电微生物(Electricigens)的发现,使得微生物燃料电池概念的内涵发生了根本性的变化,展现了广阔的应用前景。这种微生物能够以电极作为唯一电子受体,把氧化有机物获得的电子通过电子传递链传递到电极产生电流,同时微生物从中获得能量而生长。这种代谢被认为是一种新型微生物呼吸方式。以这种新型微生物呼吸方式为基础的微生物燃料电池可以同时进行废水处理和生物发电,有望可以把废水处理发展成一个有利可图的产业,是MFC最有发展前景的方向。     

微生物燃料电池在固体废物堆肥中的应用进展

微生物燃料电池(Microbial fuel cell,MFC)是一种近几年快速发展的废物处理与能源化技术,可以与污水处理、污染物降解、脱盐等环境技术结合。微生物燃料电池与堆肥技术结合可以在处理日益增长的固体废弃物的同时回收能量,具有很好的发展前景。文中分析了堆肥微生物燃料电池系统的微生物特征,探讨了堆肥过程中影响微生物燃料电池产电性能的因素,包括电极,隔膜,供氧和构型。最后归纳说明了堆肥微生物电池作为一种新的废弃物处理技术的特点:较高的微生物量并可产生较高的电流密度;对不同环境的适应性强;可以自身调节温度,能源利用效率高;质子从阳极向阴极的移动会受到不同堆肥原料的影响。     

微生物燃料电池内阻及其影响因素分析

微生物燃料电池(MFC)是一种通过微生物的催化作用将有机物中的化学能直接转化为电能的生物反应装置,研究表明内阻是限制微生物燃料电池产能的重要因素。本文对目前国内外有关微生物燃料电池内阻的研究成果进行了总结,系统介绍了微生物燃料电池内阻定义、构成和常用的微生物燃料电池内阻测定方法,重点分析了反应器、产电底物、产电微生物和操作条件等对微生物燃料电池内阻的影响,并结合已有的研究结果提出了降低内阻、提高微生物燃料电池产电性能的可行性方法。     

微生物燃料电池中阳极产电微生物的研究进展

微生物燃料电池（MFC）是利用阳极产电微生物为催化剂降解有机废物直接将化学能转化为电能的装置。在MFC系统中,产电微生物是影响产电性能的核心要素之一。介绍了MFC中产电微生物的最新研究现状,详细讨论了产电微生物的种类、产电机理和产电能力．为产电微生物的富集、驯化、改造和多种菌种优化组合提供思路。     

人工湿地-微生物燃料电池耦合系统的研究进展

人工湿地-微生物燃料电池耦合系统(CW-MFC)是一种将人工湿地技术(CW)和微生物燃料电池技术(MFC)结合在一起的新型污水处理系统,其产电机理是产电微生物在底层湿地(阳极)的厌氧条件下生成电子,通过外电路传递到表面湿地(阴极)完成氧化还原反应。但是,近几年来,关于CW-MFC研究的文章较少且研究深度较浅。综述了电极材料、水力条件、湿地植物及微生物等条件对CW-MFC污水处理能力和产电能力的影响。在电极材料方面,选用导电性、吸附性及有效面积大的材料作为电极可有效提高CW-MFC产电与去污能力;在水利条件方面,在HRT为2-3 d的条件下,应选用升流式或升流-降流式的入水方式;湿地植物方面,种植湿地植物的CW-MFC在去污和产电能力上都要优于未种植植物的CW-MFC;微生物方面,阴极与阳极的微生物群落结构存在明显的差异,但存在的产电菌的种类却十分相似。CW-MFC中存在的常见产电微生物主要包括地杆菌属(Geobacter)、脱硫叶菌属(Desulfobulbus)、假单胞菌属(Pseudomona)和脱硫弧菌属(Desulfovibrio)等。最后对CW-MFC的研究方向进行了分析,以期为CW-MFC的实际应用提供理论依据。     

沉积型海底微生物燃料电池构建及其影响因素研究

海底微生物燃料电池具有底物丰富、可长期运行、维护成本低和环境友好等特点,具有很好的研究价值和广阔的发展前景。但由于其低的功率密度输出和长期运行的不稳定性,使海底微生物燃料电池尚未得到广泛地实际应用。选取海底沉积泥用于实验室构建的海底微生物燃料电池装置中,比较了在不同阳极材料、阴阳极面积比、阳极修饰、阳极泥下深度条件下海底微生物燃料电池的功率密度输出及其电化学性能,得出最佳的海底微生物燃料电池阳极材料为碳毡;阴极及电极最佳面积比为1∶1;最佳阳极修饰为氨水浸渍;最佳阳极泥下深度为2 cm。     

关于微生物燃料电池底物的研究进展

近年来,微生物燃料电池已引起了广泛关注,它将低能量废水和木质纤维素生物质等有机废物转化为电能。在将来,微生物电能将成为一种重要的生物能源,因为微生物燃料电池提供了一种复合有机物和可再生生物能源中提取电能的可行性。人们研究了许多物质,以考察其是否能作为微生物电能转化的底物。这些物质包括人工的和天然废物,以及木质纤维素生物质。尽管现在微生物燃料电池提供的电流和功率较低,但是随着技术的发展和对微生物燃料电池系统的深入了解,微生物燃料电池转化的电流和电力将极大增加,从而向世人提供了一种可以将纤维素生物质和废水直接转化为有用能源的有效方法。本文介绍了迄今为止在微生物燃料电池中用到的各种反应底物,并对它们的应用效率和存在的不足进行了分析。     

微生物燃料电池中产电微生物的研究进展

微生物燃料电池(Microbial fuel cell,MFC)作为一种新型的环境治理和能源技术,目前已得到研究者们的广泛关注。微生物燃料电池是一种利用微生物将有机物中的化学能转化成电能的装置,产电微生物作为生物催化剂,对微生物燃料电池的发展至关重要。不同种类的产电微生物,其电子转移机制与能力有所差异,直接影响MFC的产电性能,从而决定MFC在工程实践中的性能与应用。任何含有大量微生物的废水、污泥、沉积物都可以作为产电微生物的筛选来源,尝试从不同环境条件下分离筛选高效产电微生物有望促进MFC的进一步完善,从而加速其在环境中的应用。通过对微生物燃料电池的发展、产电微生物种类及其电子传递机制等进行总结分析,综述了MFC中产电微生物的最新研究进展,包括产电微生物的筛选方法、种类以及技术研究等,最后展望了今后在产电微生物方面的主要研究方向及MFC的发展前景,以期为产电微生物的的筛选和应用奠定相应的理论基础及提供思路。     

矩形微生物燃料电池性能的分析

测试阳极液和阴极液的pH值和电导率的变化情况, 分析微生物燃料电池(MFC)的产电过程和能量利用情况, 为改善MFC的性能提供理论依据。试验结果表明: 随着MFC的运行, 阳极液的pH值和电导率呈现下降的趋势, 阴极液的pH值和电导率呈现上升的趋势, 阴极液的pH值比阳极液的pH值大约高0.30?0.50, 阳极液和阴极液的平均电导率变化不大。MFC稳定运行时, 欧姆内阻为29.69 Ω, 极限电流为2.69 mA, 最大输出功率约为0.8 mW, 对应的内阻约为95.72 Ω。铁氰化钾的质量传输是极限电流的限制性因素。能量分析发现, MFC阳极液中91.1%的葡萄糖被其他微生物消耗, 仅有8.9%的葡萄糖用来发电; 而用来发电的葡萄糖的88.5%的能量转化为其他形式的能量, 仅有11.5%的能量转化为电能。     

微生物燃料电池阳极产电微生物和阴极受体特性及研究进展

介绍微生物燃料电池的基本工作原理。根据电子传递方式阳极产电微生物分为无需中间体微生物和需中间体微生物。对阴极进行不同反应所涉及的最终电子受体进行了概述,并展望了微生物燃料电池的应用前景。     

Electricity from microorganisms

Over the last ten years, the recently discovered process of direct electron transfer from anaerobically grown microorganisms to an electrode of a fuel cell has been the object of intense study. The microorganisms responsible for such electron transport were termed electrogenic; the devices using them to generate electric current, microbial fuel cells (MFCs). The review discussed the molecular mechanisms of electron transfer to the environment in the case of the two best studied microorganisms, Shewanella oneidensis and Geobacter sulfurreducens. The discovery of bacterial conducting pili (nanowires) used for electron transfer to the electrode and between bacterial cells was sensational. In the real MFCs, which use complex substrates (industrial liquid waste), microbial associations are active, often as biofilms. The progress in MFCs design and the prospects of their practical application are considered.     

Simultaneous organics removal and bio-electrochemical denitrification in microbial fuel cells

Simultaneous organics removal and bio-electrochemical denitrification using a microbial fuel cell (MFC) reactor were investigated in this study. The electrons produced as a result of the microbial oxidation of glucose in the anodic chamber were transferred to the anode, which then flowed to the cathode in the cathodic chamber through a wire, where microorganisms used the transferred electrons to reduce the nitrate. The highest power output obtained on the MFCs was 1.7 mW/m(2) at a current density of 15 mA/m(2). The maximum volumetric nitrate removal rate was 0.084 mg NO(3)(-)-N cm(-2) (electrode surface area) day(-1). The coulombic efficiency was about 7%, which demonstrated that a substantial fraction of substrate was lost without current generation.     

Challenges in microbial fuel cell development and operation

A microbial fuel cell (MFC) is a device that converts chemical energy into electricity through the catalytic activities of microorganisms. Although there is great potential of MFCs as an alternative energy source, novel wastewater treatment process, and biosensor for oxygen and pollutants, extensive optimization is required to exploit the maximum microbial potential. In this article, the main limiting factors of MFC operation are identified and suggestions are made to improve performance.     

Electricity generation from cellulose by rumen microorganisms in microbial fuel cells

In microbial fuel cells (MFCs) bacteria generate electricity by mediating the oxidation of organic compounds and transferring the resulting electrons to an anode electrode. The objective of this study was to test the possibility of generating electricity with rumen microorganisms as biocatalysts and cellulose as the electron donor in two-compartment MFCs. The anode and cathode chambers were separated by a proton exchange membrane and graphite plates were used as electrodes. The medium in the anode chamber was inoculated with rumen microorganisms, and the catholyte in the cathode compartment was ferricyanide solution. Maximum power density reached 55 mW/m(2) (1.5 mA, 313 mV) with cellulose as the electron donor. Cellulose hydrolysis and electrode reduction were shown to support the production of current. The electrical current was sustained for over 2 months with periodic cellulose addition. Clarified rumen fluid and a soluble carbohydrate mixture, serving as the electron donors, could also sustain power output. Denaturing gradient gel electrophoresis (DGGE) of PCR amplified 16S rRNA genes revealed that the microbial communities differed when different substrates were used in the MFCs. The anode-attached and the suspended consortia were shown to be different within the same MFC. Cloning and sequencing analysis of 16S rRNA genes indicated that the most predominant bacteria in the anode-attached consortia were related to Clostridium spp., while Comamonas spp. abounded in the suspended consortia. The results demonstrated that electricity can be generated from cellulose by exploiting rumen microorganisms as biocatalysts, but both technical and biological optimization is needed to maximize power output.     

Response to starvation and microbial community composition in microbial fuel cells enriched on different electron donors

In microbial fuel cells (MFCs), microorganisms generate electrical current by oxidizing organic compounds. MFCs operated with different electron donors harbour different microbial communities, and it is unknown how that affects their response to starvation. We analysed the microbial communities in acetate- and glucose-fed MFCs and compared their responses to 10 days starvation periods. Each starvation period resulted in a 4.2 ± 1.4% reduction in electrical current in the acetate-fed MFCs and a 10.8 ± 3.9% reduction in the glucose-fed MFCs. When feed was resumed, the acetate-fed MFCs recovered immediately, whereas the glucose-fed MFCs required 1 day to recover. The acetate-fed bioanodes were dominated by Desulfuromonas spp. converting acetate into electrical current. The glucose-fed bioanodes were dominated by Trichococcus sp., functioning as a fermenter, and a member of Desulfuromonadales, using the fermentation products to generate electrical current. Suspended biomass and biofilm growing on non-conductive regions within the MFCs had different community composition than the bioanodes. However, null models showed that homogenizing dispersal of microorganisms within the MFCs affected the community composition, and in the glucose-fed MFCs, the Trichococcus sp. was abundant in all locations. The different responses to starvation can be explained by the more complex pathway requiring microbial interactions to convert glucose into electrical current.     

Photosynthetic microbial fuel cells with positive light response

The current study introduces an aerobic single‐chamber photosynthetic microbial fuel cell (PMFC). Evaluation of PMFC performance using naturally growing fresh‐water photosynthetic biofilm revealed a weak positive light response, that is, an increase in cell voltage upon illumination. When the PMFC anodes were coated with electrically conductive polymers, the rate of voltage increased and the amplitude of the light response improved significantly. The rapid immediate positive response to light was consistent with a mechanism postulating that the photosynthetic electron‐transfer chain is the source of the electrons harvested on the anode surface. This mechanism is fundamentally different from the one exploited in previously designed anaerobic microbial fuel cells (MFCs), sediment MFCs, or anaerobic PMFCs, where the electrons are derived from the respiratory electron‐transfer chain. The power densities produced in PMFCs were substantially lower than those that are currently reported for conventional MFC (0.95 mW/m² for polyaniline‐coated and 1.3 mW/m² for polypyrrole‐coated anodes). However, the PMFC did not depend on an organic substrate as an energy source and was powered only by light energy. Its operation was CO₂‐neutral and did not require buffers or exogenous electron transfer shuttles. Biotechnol. Bioeng. 2009; 104: 939–946. © 2009 Wiley Periodicals, Inc.     

A state of the art review on microbial fuel cells: A promising technology for wastewater treatment and bioenergy

A microbial fuel cell (MFC) is a bioreactor that converts chemical energy in the chemical bonds in organic compounds to electrical energy through catalytic reactions of microorganisms under anaerobic conditions. It has been known for many years that it is possible to generate electricity directly by using bacteria to break down organic substrates. The recent energy crisis has reinvigorated interests in MFCs among academic researchers as a way to generate electric power or hydrogen from biomass without a net carbon emission into the ecosystem. MFCs can also be used in wastewater treatment facilities to break down organic matters. They have also been studied for applications as biosensors such as sensors for biological oxygen demand monitoring. Power output and Coulombic efficiency are significantly affected by the types of microbe in the anodic chamber of an MFC, configuration of the MFC and operating conditions. Currently, real-world applications of MFCs are limited because of their low power density level of several thousand mW/m2. Efforts are being made to improve the performance and reduce the construction and operating costs of MFCs. This article presents a critical review on the recent advances in MFC research with emphases on MFC configurations and performances.     

Electroactive bacteria—molecular mechanisms and genetic tools

In nature, different bacteria have evolved strategies to transfer electrons far beyond the cell surface. This electron transfer enables the use of these bacteria in bioelectrochemical systems (BES), such as microbial fuel cells (MFCs) and microbial electrosynthesis (MES). The main feature of electroactive bacteria (EAB) in these applications is the ability to transfer electrons from the microbial cell to an electrode or vice versa instead of the natural redox partner. In general, the application of electroactive organisms in BES offers the opportunity to develop efficient and sustainable processes for the production of energy as well as bulk and fine chemicals, respectively. This review describes and compares key microbiological features of different EAB. Furthermore, it focuses on achievements and future prospects of genetic manipulation for efficient strain development.     

Electricity generation from carbon monoxide and syngas in a microbial fuel cell

Electricity generation in microbial fuel cells (MFCs) has been a subject of significant research efforts. MFCs employ the ability of electricigenic bacteria to oxidize organic substrates using an electrode as an electron acceptor. While MFC application for electricity production from a variety of organic sources has been demonstrated, very little research on electricity production from carbon monoxide and synthesis gas (syngas) in an MFC has been reported. Although most of the syngas today is produced from non-renewable sources, syngas production from renewable biomass or poorly degradable organic matter makes energy generation from syngas a sustainable process, which combines energy production with the reprocessing of solid wastes. An MFC-based process of syngas conversion to electricity might offer a number of advantages such as high Coulombic efficiency and biocatalytic activity in the presence of carbon monoxide and sulfur components. This paper presents a discussion on microorganisms and reactor designs that can be used for operating an MFC on syngas.     

Use of acetate for enrichment of electrochemically active microorganisms and their 16S rDNA analyses

A fuel cell-type electrochemical device has been used to enrich microbes oxidizing acetate with concomitant electricity generation without using an electron mediator from activated sludge. The device generated a stable current of around 5 mA with complete oxidation of 5 mM acetate at the hydraulic retention time of 2.5 h after 4 weeks of enrichment. Over 70% of electrons available from acetate oxidation was recovered as current. Carbon monoxide or hydrogen did not influence acetate oxidation or current generation from the microbial fuel cell (MFC). Denaturing gradient gel electrophoresis showed that DNA extracted from the acetate-enriched MFC had different 16S rDNA patterns from those of sludge or glucose+glutamate-enriched MFCs. Nearly complete 16S rDNA sequence analyses showed that diverse bacteria were enriched in the MFC fed with acetate. Electron microscopic observations showed biofilm developed on the electrode, but not microbial clumps observed in MFCs fed with complex fuel such as glucose and wastewater from a corn-processing factory.