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。     

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。     

垃圾填埋场N_2O排放通量及测定方法研究进展

氧化亚氮(N2O)是第三大温室气体和最主要的臭氧层破坏气体.填埋是目前城市生活垃圾处理处置的主要方式,而垃圾填埋场是N2O的排放源之一.实验室研究和现场测定均表明,生活垃圾填埋场可以有高的N2O释放通量,但不同填埋场测定数据差异很大.目前,对生活垃圾填埋场N2O排放量的原位准确测定以及排放机理和重要性的认识仍有很多不足.本文概述了生活垃圾填埋场N2O排放研究现状,从垃圾堆体和覆土层两部分探讨了传统厌氧卫生填埋场的N2O产生和排放机理,并就此对新型脱氮型生物反应器填埋场做了相应探讨.最后,就静态箱法、涡度相关法等N2O通量测定方法在填埋场的适用性进行了讨论,并展望了填埋场N2O排放的研究方向.     

垃圾填埋场N2O排放通量及测定方法研究进展

氧化亚氮(N₂O)是第三大温室气体和最主要的臭氧层破坏气体.填埋是目前城市生活垃圾处理处置的主要方式,而垃圾填埋场是N₂O的排放源之一.实验室研究和现场测定均表明,生活垃圾填埋场可以有高的N₂O释放通量,但不同填埋场测定数据差异很大.目前,对生活垃圾填埋场N₂O排放量的原位准确测定以及排放机理和重要性的认识仍有很多不足.本文概述了生活垃圾填埋场N₂O排放研究现状,从垃圾堆体和覆土层两部分探讨了传统厌氧卫生填埋场的N₂O产生和排放机理,并就此对新型脱氮型生物反应器填埋场做了相应探讨.最后,就静态箱法、涡度相关法等N₂O通量测定方法在填埋场的适用性进行了讨论,并展望了填埋场N₂O排放的研究方向.     

太阳能电池协同微生物燃料电池产电及对底泥的修复影响

装置以河道黑臭底泥为底物, 改性后的碳毡为电极, 通过外接不同额定电压的太阳能电池板, 构建了一种新型的SC-MFC (solar cell-microbial fuel cell) 体系, 太阳能电池的引入对普通MFC 产电性能及底泥污染物去除效率产生了的影响。通过一个周期的运行, 得到如下结论: 在太阳能电池表面辐照强度53 mW·cm^–2 的条件下, SC-MFC 系统的最大输出电压和输出功率密度与普通的MFC 相比均有明显的提高。对于底泥污染物的去除, SC-MFC 系统随着串联太阳能电池额定电压的增大, 去除效率呈现出先升高后降低的趋势。在外接0.5 V、1 V、2 V 太阳能电池时, 底泥对污染物修复效果较好, 并且底泥中有机质、总磷、氨氮、硝态氮的最大去除率为20.88%、32.39%、48.41%、62.66%, 它们分别在串联1 V、2 V、2 V、0.5 V 太阳能电池板时达到。     

微生物燃料电池中产电微生物的研究进展

产电微生物是微生物燃料电池系统的核心组成, 本文从生物学角度介绍了几种产电微生物的分类学地位、形态特征、生理生化特征及在微生物燃料电池中的产电机理和产电能力, 分析了利用产电微生物进行废水处理同时生物发电的应用前景, 提出产电微生物在MFC系统中的进一步研究方向为微生物的富集、驯化、改造和多种菌种优化组合等。     

微生物燃料电池中产电微生物的系统发育分析及筛选

对污水处理厂曝气池的产电微生物进行富集并利用纯培养法筛选,采用基于16S rRNA基因序列的系统发育分析方法研究了产电微生物的生物多样性,并基于三电极体系绘制出的循环伏安曲线鉴别出产电性能较强的纯菌株。结果表明,菌株F003、F042和F050与其系统发育关系最密切的有效发表种的典型菌株的16S rRNA基因序列存在较大差异,分别代表新的分类单元。之后又对所获得的38株菌株进行电化学测试活性,得出4株活性较强的菌株,其中菌株F010和F017的电化学活性比菌株F007和F051更为显著。     

微生物燃料电池中假单胞菌F026的产电性能研究

基于微生物燃料电池的反应装置,从污水处理厂曝气池的污泥中通过富集,筛选和基于16S rRNA基因序列的系统发育分析等手段驯化出1株高效产电假单胞菌F026。以F026为阳极产电菌制作微生物燃料电池,考察了底物种类、温度和p H值等因素对微生物燃料电池产电性能的影响。结果表明,F026最适合在以可溶性淀粉为底物,p H为中性偏碱性,温度在30~35℃的环境下生长。在此条件下,微生物燃料电池的最高电压达到500 m V,体积功率密度达到2 W/m3。     

“共轭聚合物-产电菌”复合生物电极构建及其在微生物燃料电池中的应用

微生物燃料电池(Microbial fuel cell,MFC)作为一种生物电化学装置,在可再生能源生产和废水处理方面的巨大潜力已引起广泛关注。然而MFC面临输出功率低、欧姆内阻高以及启动时间长等问题,极大限制了其在实际工程中的应用。MFC中阳极是微生物附着的载体,对电子的产生及传递起着关键作用,开发优质的生物电极已发展成为改善MFC性能的有效途径。共轭聚合物具有成本低、电导率高、化学稳定性及生物相容性好等优点,利用共轭聚合物修饰生物电极结构,可以实现大比表面积、缩短电荷转移路径,从而实现高效生物电化学性能。同时,纳米级共轭聚合物包覆细菌,可以使细菌产生的电子有效地传递到电极。文中综述了最近报道的共轭聚合物在MFC中的应用,重点介绍了共轭聚合物修饰的MFC阳极,系统分析了共轭聚合物的优点及局限性,以及这些高效复合生物电极如何解决MFC应用中存在的低输出功率、高欧姆内阻及长启动时间等问题。     

New exoelectrogen Citrobacter sp. SX-1 isolated from a microbial fuel cell

Aims: Isolation, identification and characterization of a new exoelectrogenic bacterium from a microbial fuel cell (MFC). Methods and Results: Exoelectrogenic bacterial strain SX‐1 was isolated from a mediator‐less MFC by conventional plating techniques with ferric citrate as electron acceptor under anaerobic condition. Phylogenetic analysis of the 16S rDNA sequence revealed that it was related to the members of Citrobacter genus with Citrobacter sp. sdy‐48 being the most closely related species. The bacterial strain SX‐1 produced electricity from citrate, acetate, glucose, sucrose, glycerol and lactose in MFCs with the highest current density of 205 mA m^?2 generated from citrate. Cyclic voltammetry analysis indicated that membrane‐associated proteins may play an important role in facilitating the electrons transferring from bacteria to electrode. Conclusions: This is the first study that demonstrates that Citrobacter species can transfer electrons to extracellular electron acceptors. Citrobacter strain SX‐1 is capable of generating electricity from a wide range of substrates in MFCs. Significance and Impact of the Study: This finding increases the known diversity of power generating exoelectrogens and provided a new strain to explore the mechanisms of extracellular electron transfer from bacteria to electrode. The wide range of substrate utilization by SX‐1 increases the application potential of MFCs in renewable energy generation and waste treatment.     

Effects of sediment pretreatment on the performance of sediment microbial fuel cells

In the present study, the effects of different pretreatment methods for sediments on the performance of sediment microbial fuel cells (SMFCs) were evaluated. Autoclaved (30 and 60 min), and heated (150 °C, 3 h) sediments demonstrated high power density, compared with control and heated (60 °C, 3 h) sediments. An SMFC with heated (60 °C, 3 h) sediment was found to easily form a biocathode. The power density of an SMFC with heated (150 °C, 3 h) sediment was 214 mW m(-2) on day 24. Furthermore, autoclaved (30 and 60 min) and heated (3 h, 60 and 150 °C) sediments accelerated the production of dissolved organic matter (DOM). The DOM in heated (60 °C, 3 h) sediments had larger molecular sizes. The present study demonstrates that SMFCs can have high power density and high loss on ignition removal efficiencies when produced from sediments by suitable pretreatment methods.     

Performance and microbial diversity of palm oil mill effluent microbial fuel cell

Aim: To evaluate the bioenergy generation and the microbial community structure from palm oil mill effluent using microbial fuel cell. Methods and Results: Microbial fuel cells enriched with palm oil mill effluent (POME) were employed to harvest bioenergy from both artificial wastewater containing acetate and complex POME. The microbial fuel cell (MFC) showed maximum power density of 3004 mW m^?2 after continuous feeding with artificial wastewater containing acetate substrate. Subsequent replacement of the acetate substrate with complex substrate of POME recorded maximum power density of 622 mW m^?2. Based on 16S rDNA analyses, relatively higher abundance of Deltaproteobacteria (88·5%) was detected in the MFCs fed with acetate artificial wastewater as compared to POME. Meanwhile, members of Gammaproteobacteria, Epsilonproteobacteria and Betaproteobacteria codominated the microbial consortium of the MFC fed with POME with 21, 20 and 18·5% abundances, respectively. Conclusions: Enriched electrochemically active bacteria originated from POME demonstrated potential to generate bioenergy from both acetate and complex POME substrates. Further improvements including the development of MFC systems that are able to utilize both fermentative and nonfermentative substrates in POME are needed to maximize the bioenergy generation. Significance and Impact of the Study: A better understanding of microbial structure is critical for bioenergy generation from POME using MFC. Data obtained in this study improve our understanding of microbial community structure in conversion of POME to electricity.     

Conduction-based modeling of the biofilm anode of a microbial fuel cell

The biofilm of a microbial fuel cell (MFC) experiences biofilm-related (growth and mass transport) and electrochemical (electron conduction and charger-transfer) processes. We developed a dynamic, one-dimensional, multi-species model for the biofilm in three steps. First, we formulated the biofilm on the anode as a "biofilm anode" with the following two properties: (1) The biofilm has a conductive solid matrix characterized by the biofilm conductivity (kappa(bio)). (2) The biofilm matrix accepts electrons from biofilm bacteria and conducts the electrons to the anode. Second, we derived the Nernst-Monod expression to describe the rate of electron-donor (ED) oxidation. Third, we linked these components using the principles of mass balance and Ohm's law. We then solved the model to study dual limitation in biofilm by the ED concentration and local potential. Our model illustrates that kappa(bio) strongly influences the ED and current fluxes, the type of limitation in biofilm, and the biomass distribution. A larger kappa(bio) increases the ED and current fluxes, and, consequently, the ED mass-transfer resistance becomes significant. A significant gradient in ED concentration, local potential, or both can develop in the biofilm anode, and the biomass actively respires only where ED concentration and local potential are high. When kappa(bio) is relatively large (i.e., > or =10(-3) mS cm(-1)), active biomass can persist up to tens of micrometers away from the anode. Increases in biofilm thickness and accumulation of inert biomass accentuate dual limitation and reduce the current density. These limitations can be alleviated with increases in the specific detachment rate and biofilm density.     

微生物燃料电池在环境污染治理研究中的应用进展

近年来,微生物燃料电池(Microbial fuel cells,MFCs)研究得到了迅速发展。由于可以将可生物降解有机物的化学能直接转化为电能,MFCs在环境污染治理及生物产电方面具有良好的应用前景。本文将全面介绍和总结MFCs在环境污染治理中的研究及应用,其中包括脱氮、脱硫、有机污染物降解、重金属污染治理以及垃圾渗滤液处理等方面。此外,本文还提出MFCs在研究及应用过程中存在的主要问题,并对其研究前景进行展望。     

Long‐term effects of the transient COD concentration on the performance of microbial fuel cells

In this work, the long‐term effects of transient chemical oxygen demands (COD) concentrations over the performance of a microbial fuel cell were studied. From the obtained results, it was observed that the repetitive change in the COD loading rate during 12 h conditioned the behavior of the system during periods of up to 7 days. The main modifications were the enhancement of the COD consumption rate and the exerted current. These enhancements yielded increasing Coulombic efficiencies (CEs) when working with COD concentrations of 300 mg/L, but constant CEs when working with COD concentrations from 900 to 1800 mg/L. This effect could be explained by the higher affinity for the substrate of Geobacter than that of the nonelectrogenic organisms such as Clostridia. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:883–890, 2016     

Quinones as terminal electron acceptors for anaerobic microbial oxidation of phenolic compounds

The capacity of anaerobic granular sludge for oxidizing phenoland p-cresol under anaerobic conditions was studied. Phenol and p-cresolwere completely converted to methane when bicarbonate was the only terminal electron acceptor available. When the humic model compound, anthraquinone-2,6-disulfonate, was included as an alternative electron acceptor in the cultures, the oxidation of the phenolic compounds was coupled to the reduction of the model humic compound to its corresponding hydroquinone, anthrahydroquinone-2,6-disulfonate. These results demonstrate for the first time that the anaerobic degradation of phenolic compounds can be coupled to the reduction of quinones as terminal electron acceptor.     

Analysis of ammonia loss mechanisms in microbial fuel cells treating animal wastewater

Ammonia losses during swine wastewater treatment were examined using single- and two-chambered microbial fuel cells (MFCs). Ammonia removal was 60% over 5 days for a single-chamber MFC with the cathode exposed to air (air-cathode), versus 69% over 13 days from the anode chamber in a two-chamber MFC with a ferricyanide catholyte. In both types of systems, ammonia losses were accelerated with electricity generation. For the air-cathode system, our results suggest that nitrogen losses during electricity generation were increased due to ammonia volatilization with conversion of ammonium ion to the more volatile ammonia species as a result of an elevated pH near the cathode (where protons are consumed). This loss mechanism was supported by abiotic tests (applied voltage of 1.1 V). In a two-chamber MFC, nitrogen losses were primarily due to ammonium ion diffusion through the membrane connecting the anode and cathode chambers. This loss was higher with electricity generation as the rate of ammonium transport was increased by charge transfer across the membrane. Ammonia was not found to be used as a substrate for electricity generation, as intermittent ammonia injections did not produce power. The ammonia-oxidizing bacterium Nitrosomonas europaea was found on the cathode electrode of the single-chamber system, supporting evidence of biological nitrification, but anaerobic ammonia-oxidizing bacteria were not detected by molecular analyses. It is concluded that ammonia losses from the anode chamber were driven primarily by physical-chemical factors that are increased with electricity generation, although some losses may occur through biological nitrification and denitrification.     

Effects of inoculation strategy and cultivation approach on the performance of microbial fuel cell using marine sediment as bio-matrix

Aims: To investigate the effects of inoculation strategy and cultivation approach on the performance of microbial fuel cell (MFC). Methods and Results: A dual‐chamber sediment fuel cell was set up fed with glucose under batch condition. At day 30, the supernatant consortium was partly transferred and used as inoculum for the evaluation of cultivation approach. Power output gradually increased to 9·9 mW m^?2 over 180 days, corresponding to coulombic efficiency (CE) of 29·6%. Separated biofilms attached anode enabled power output and CE dramatically up to 100·9 mW m^?2 and over 50%, respectively, whereas the residual sediment catalysed MFC gave a poor performance. MFC catalysed by in situ supernatant consortium demonstrated more than twice higher power than MFC catalysed by the supernatant consortium after Fe(OH)₃ cultivation. However, the re‐generation of biofilms from the latter largely enhanced the cell performance. Conclusions: MFC exhibited a more efficient inducement of electroactive consortium than Fe(OH)₃ cultivation. MFC performance varied depending on different inoculation strategies. Significance and Impact of the Study: This is the first time to study cultivation approach affecting electricity generation. In addition, anodic limitations of mass and electron transfer were discussed through MFC catalysed by sediment‐based bio‐matrix.