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The catalytic microorganisms oxidise the organic matter to produce electrical energy in microbial fuel cells (MFCs). The microorganisms that can shuttle the electrons exogenously to the electrode surface without utilising artificial mediators are referred as exoelectrogens. The microorganisms produce specific proteins or genes for their inevitable...
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... (MFCs) are fascinating bio- logical fuel cells that typically contain two com- partments, i.e. the anode and the cathode, and use biological catalysts (mostly bacteria) to produce electric energy from organic matter present natu- rally in the environment or in waste ( Wang and Ren 2013 ). General principle of a microbial fuel cell is presented in Fig. 9.1 . The microorganisms that act as biocatalysts oxidise organic and inor- ganic substrate to carbon dioxide and generate electrons at the anode. It requires transferring these electrons from inside the cells to the anode (surface) in anoxic conditions to produce electric current (Logan and Rabaey 2012 ). The bacteria can transfer these ...
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... can transfer electrons to an elec- trode directly by three mechanisms (see Fig. 9.2 ) known till date: (1) short-range electron transfer via redox-active proteins such as cytochromes present on the outer surface of bacterial cell membrane; (2) electron transport via microbial- secreted soluble electron shuttles, for example, fl avins and pyocyanin; and (3) long-range elec- tron transfer through conductive ...
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... microorganisms have already been used as biocathodes in the technology, but only limited information is available on electron transport mechanisms from electrode to microbes. Though, it's clear that microorganisms use different mech- anisms to accept electrons from the cathode (see Fig. 9.3 ) than to donate electrons to the ...
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... revealed that Cyt 579 (structurally, 70 % α-helical) is localised in periplasmic space ( Jeans et al. 2008 ) and helps in accepting the electrons derived from Fe (II) oxidation ( Jeans et al. 2008 ). Similarly, another unusual membrane protein, Cyt 572 (structurally, β-helical), isolated from aci- dophilic microbial communities showed the abil- Fig. 9.3 Mechanisms of electron transfers from electrode to microorganisms ity for Fe (II) oxidation ( Jeans et al. 2008 ), but it's still elusive that the protein participates in electron transfer mechanisms. Recently, cyclic voltammetry scanned an unidentifi ed redox- active molecule secreted from P. aeruginosa , involved in the electron ...
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Based on the catalytic properties of electrochemically active organisms, activated-sludge based-microbial fuel cell (MFC) system was designed for the electricity generation. As a microbial energy source, glucose has been exploited as electron provider. During the incubation time of bacterial culture in a mediated-less MFC, the cell voltage and degr...
The electron shuttling process has been recognized as an important microbial respiration process. Because the incubation temperature can influence both the reactivity of electron mediators and cell growth, it may also affect the electron-shuttle-mediated extracellular electron transfer (EET) process. Here, the effect of incubation temperature (22–3...
Shear stress is an important factor that affects the formation and structure of anode biofilms, which are strongly related to the extracellular electron transfer phenomena and bioelectric performance of bioanodes. Here, we show that using nitrogen sparging to induce shear stress during anode biofilm formation increases the linear sweep voltammetry...
Based on the catalytic properties of electrochemically active organisms, activated-sludge based-microbial fuel cell (MFC) system was designed for the electricity generation. As a microbial energy source, glucose has been exploited as electron provider. During the incubation time of bacterial culture in a mediated-less MFC, the cell voltage and degr...
BACKGROUND
The c‐type cytochrome of the CymA of Shewanella oneidensis MR‐1 is essential for the anaerobic respiration of Shewanella sp. and transfers electrons from the inner membrane to various terminal electron acceptors, such as soluble redox shuttles and insoluble metal oxides. CymA is believed to be a passage to the outer membrane for dissipat...
Citations
... Microorganisms can effectively help in the production of energy capable of completely oxidizing organic compounds and transferring electrons to the anode at accelerated rates. Studies have shown that mixedculture biofilms have a greater ability to produce higher current density than pureculture biofilms [9]. ...
In this chapter, after describing how the microbial fuel cell operates and how the chemical energy resulting from the oxidation of a substrate through oxidation/reduction reactions is converted into electricity with chemical reactions, the factors affecting the performance of the fuel cell including the effect of temperature, the effect pH, external resistance, type of electrode, size, and distance of electrodes, type, and composition of microorganisms, as well as the shape, structure, and size of the chamber have been investigated. Since the purpose of fuel cell design is to produce electric current from microorganisms, therefore, the current density criterion and how to calculate it are briefly explained.
... During this process, they are transferred, to an insoluble anode of the bioelectrochemical system (BES), instead of the corresponding natural acceptors (oxygen, sulfates, ferriions, nitrates, etc.). Various electroactive microorganisms are used to carry out the process, including mixed cultures isolated from natural habitats (Kumar et al., 2015). ...
The possibilities of simultaneous removal of sulfates and heavy metals (Cu, Ni, Zn) from acid mine drainage have been investigated in two-section bioelectrochemical system (BES). The used BES is based on the microbial sulfate reduction (MSR) process in the anode zone and abiotic reduction processes in the cathodic zone. In the present study, the model acid mine drainage with high sulfate (around 4.5 g/l) and heavy metals (Cu2+, Ni2+ and Zn2+) content was performed. As a separator in the laboratory, BES used an anionic exchange membrane (AEM), and for electron donor in the process of microbial sulfate reduction in the bioanode zone – waste ethanol stillage from the distillery industry was employed.
In this study, the possibility of sulfates removal from the cathodic zone was established by their forced migration through AEM to the anode zone. Simultaneously, as a result of the MSR process, the sulfate ions passed through AEM are reduced to H2S in the anode zone. The produced H2S, having its role as a mediator in electron transfer, is oxidized on the anode surface to S0 and other forms of sulfur. The applicability of waste ethanol stillage as a cheap and affordable organic substrate for the MSR process has also been established.
Heavy metals (Cu2+, Ni2+ and Zn2+) occur in the cathode chamber of BES in different degrees of the removal. As a microbial fuel cell (MFC) operating for 120 hours, the reduction rate of Cu2+ reaches 94.6% (in waste ethanol stillage) and 98.6% (in the case of Postgate culture medium). On the other hand, in terms of Ni2+ and Zn2+, no significant decrease in their concentrations in the liquid phase is found. In the case of microbial electrolysis cell (MEC) mode reduction of Cu2+- 99.9%, Ni2+- 65.9% and Zn2+- 64.0% was achieved. For 96 hours, the removal of sulfates in MEC mode reached 69.9% in comparison with MFC mode – 35.2%.
... The flow of electrons from the anode to the cathode generates current and voltage, which are then converted into electricity in the MFC system (Kumara Behera and Varma 2016). In the fermentative metabolism, the electricity generated in the MFC system tends to be lower because the electrons reside in the fermentation product (Kumar et al. 2015). ...
Fauzan IA, Meryandini A, Ridwan R, Fidriyanto R, Agustini NWS, Santosa DA. 2022. Coupling Indonesian indigenous Citrobacter freundii and Chlorella pyrenoidosa strain on the anode of microbial fuel cell with various substrates. Biodiversitas 23: 2471-2481. Microorganism plays a crucial role in the development of MFC systems. Indigenous to Indonesia, Citrobacter freundii GBH253 is a potential exoelectrogenic bacterium that could be developed into an MFC system. Coupling C. freundii GBH253 with potentially electricity-producing microalgae indigenous to Indonesia, such as Chlorella pyrenoidosa INK, in the anode of an MFC, could result in a more stable and higher electricity output. This study used C. freundii GBH253 and C. pyrenoidosa INK to produce electricity in various substrates. This research was conducted using a Factorial Randomized Block Design and Tukey’s test to determine significant differences between treatments. The result shows that electricity was generated in all treatments. The Bacterium-microalgae combination in acetate substrate can generate power density up to 211,97 mW m-2 and is the most stable compared to others. Bacterium dominates the electricity production in this combination, but the microalgae also play a role in producing electricity and increasing Chemical Oxygen Demand. The pH value of all treatments was higher than 7. Volatile Fatty Acids, like acetate and phenol, were produced in all treatments, whereas butyric acid and propionic acid were produced in several treatments. The Pearson correlation showed that some VFAs are highly correlated with power density.
... These are less sensitive to temperature changes, sludge treatment plants and the associated electrical installations are limited and no energy is consumed for aeration (He et al., 2017). In a series of articles, there has been an extensive description of MFCs (Santoro et al., 2017a), their operation principle (Kumar et al., 2015;Lee et al., 2017;Mohamed et al., 2021), their electric performance (Capodalgio et al., 2015;Vilajeliu-Pons et al., 2016), the electron and ion transport mechanisms (Hubenova and Mitov, 2015;Kumar et al., 2016;Oliot et al., 2016;Sure et al., 2016;Abbas et al., 2017;Saratale et al., 2017), the biofilms (Cristiani et al., 2013;Saratale et al., 2017), the anodes (Santoro et al., 2015a;Yu et al., 2016;Hindatu et al., 2017;Sonawane et al., 2017;Cai et al., 2020;Huang et al., 2021), the cathodes (Ewusi-Mensah et al., 2021;Huang et al., 2021;Mutuma et al., 2021;Santoro et al., 2014;Santoro et al., 2015c;Sawant et al., 2017;Yu et al., 2016), the additional electrodes Soavi and Santoro, 2020), the separators/membranes (Daud et al., 2015;Oliot et al., 2016;Ghassemi and Slaughter, 2017), the mediating solutions (Yong et al., 2014;Cristiani et al., 2020;Mutuma et al., 2021), the catalysts (Santoro et al., 2015b;Santoro et al., 2016a;Santoro et al., 2017b;Santoro et al., 2017c;Santoro et al., 2017d;Santoro et al., 2017e;Santoro et al., 2018a;Santoro et al., 2018b;Santoro et al., 2020;Rojas-Carbonell et al., 2017;Kodali et al., 2017;Erable et al., 2018;Salar Garcia et al., 2019;Ficca et al., 2020;Babanova et al., 2021), the influence of operational variables , and their mathematical modeling (Kato Marcus et al., 2007;Picioreanu et al., 2007;Zeng et al., 2010;Ortiz-Martínez et al., 2015;Capodaglio et al., 2017;Jadhav et al., 2021a). Moreover, various MFCs are constructed, i.e., ceramic brick (You et al., 2019), photo , benthic (Reimer et al., 2006;Kagan et al., 2014;Karra et al., 2014;Abbas et al., 2017;Tommasi and Lombardelli, 2017), sediment (Donovan et al., 2008;Ewing et al., 2017;Mohamed et al., 2017), desalination (Borjas et al., 2017;Ewusi-Mensah et al., 2021;Moruno et al., 2018;Ramírez-Moreno et al., 2019;Ramírez-Moreno et al., 2021;Santoro et al., 2017e), supercapacitive (Santoro et al., 2016b;Walter et al., 2020b;Poli et al., 2020;Soavi and Santoro, 2020), and floating (Martinucci et al., 2015;Cristiani et al., 2019). ...
Microbial fuel cells (MFCs) have undergone great technological development in the last 20 years, but very little has been done to commercialize them. The simultaneous power production and wastewater treatment are features those greatly increase the interest in the use of MFCs. This kind of distributed power generation is renewable and friendly and can be easily integrated into a smart grid. However, there are some key issues with their commercialization: high construction costs, difficulty in developing high power structures, MFC lifespan, and maintaining a high level of efficiency. The objective of this article is to explore the possibilities of using MFCs in urban wastewater not only regarding the technical criteria of their application, but also mainly from an economic point of view, to determine the conditions through which the viability of the investment is ensured and the possibilities of their integration in a smart grid are identified. Initially, this article explores the implementation/configuration of a power plant with MFCs within an urban wastewater treatment plant on a theoretical basis. In addition, based on the corresponding physical quantities for urban wastewater treatment, the construction and operational costs are determined and the viability of the investment is examined based on classic economic criteria such as net present value, benefit–cost ratio, internal rate of return, and discounted payback period. Furthermore, sensitivity analysis is carried out, concerning both technical parameters, such as the percentage of organic matter removal, power density, sewage residence time, MFC efficiency, etc., and economical parameters, such as the reduction of construction costs due to change of materials, change of interest rate, and lifetime. The advantages and disadvantages of their use in smart grids is also analyzed. The results show that the use of MFCs for power generation cannot be utopian as long as they are integrated into the structure of a central wastewater treatment plant on the condition that the scale-up technical issues of MFCs are successfully addressed.
... In these cases, where the bacteria are weak exoelectrogens, the soluble redox shuttle that carries electrons to the solid electrodes is required to enhance or even detect the current densities provided by MFC [67]. Both forms of MD (oxidized and reduced) are neutral and lipophilic, with the molecular structure close to ubiquinone known as a membrane-bound redox mediator [68]. The electron transfer mechanism in such systems is mainly based on its permeation through the cell outer membrane and reduction by the redox enzymes to menadiol (MDred) that are located in the cytosol or mitochondria and catalyzing the electron transfer from NAD(P)H to quinone substrates [63]. ...
In this study, the nitrogen-fixing, Gram-negative soil bacteria Rhizobium anhuiense was successfully utilized as the main biocatalyst in a bacteria-based microbial fuel cell (MFC) device. This research investigates the double-chambered, H-type R. anhuiense-based MFC that was operated in modified Norris medium (pH = 7) under ambient conditions using potassium ferricyanide as an electron acceptor in the cathodic compartment. The designed MFC exhibited an open-circuit voltage (OCV) of 635 mV and a power output of 1.07mWm2 with its maximum power registered at 245 mV. These values were further enhanced by re-feeding the anode bath with 25 mM glucose, which has
been utilized herein as the main carbon source. This substrate addition led to better performance of the constructed MFC with a power output of 2.59 mW m2 estimated at an operating voltage of 281 mV. The R. anhuiense-based MFC was further developed by improving the charge transfer through the bacterial cell membrane by applying 2-methyl-1,4-naphthoquinone (menadione, MD) as a soluble redox mediator. The MD-mediated MFC device showed better performance, resulting in a slightly higher OCV value of 683 mV and an almost five-fold increase in power density to 4.93 mW cm-2. The influence of different concentrations of MD on the viability of R. anhuiense bacteria was investigated by estimating the optical density at 600 nm (OD600) and comparing the obtained results with the control aliquot. The results show that lower concentrations of MD, ranging from 1 to 10 uM, can be successfully used in an anode compartment in which R. anhuiense bacteria cells remain viable and act as a main biocatalyst for MFC applications.
... During oxidation, urease bacteria convert urea into CO 2 and NH 3 through microbial respiration. Thus, simultaneous urea degradation and electricity generation was achieved with cow dung as biocatalyst in CC-MFC [42]. Therefore, based on the observations made in the present paper, anaerobically incubated cow dung can support a wide variety of potential bacterial communities. ...
We study the direct use of cow dung compost soil as a biocatalyst to optimize the urea fuel concentrations in the range of 0.1 g/ml to 0.5 g/ml in cow dung compost microbial fuel cells (CC-MFCs). The results indicate that the CC-MFC with the urea fuel concentration of 0.4 g/ml produces the maximum power. Moreover, the bacterial population plays a vital role in electricity generation. For constant cell operation and cell sustainability, it must be refuelled with the catalyst after every 12 h cycle. This study confirms for the first time that cow dung compost directly works as a biocatalyst. Our primary focus is to generate power through soil processes using urea-rich wastewaters (urine) as fuel. CC-MFCs are inexpensive, non-toxic, leakage proof, low maintenance, less labour intensive, durable, stable, easily disposable, sustainable, and efficient. Moreover, they can generate clean energy without biocatalyst deactivation. Research is going on fabrication and development of CC-MFC for application depend upon the type of urea rich urine wastewater used as fuel for power generation and cleaning the environment.
... pyocyanin), outer membrane multiheme cytochromes (e.g. OmcZ), conductive pili predominantly in the members of Shewanellaceae and Geobacteraceae family (Kumar, Singh, & Wahid, 2015). Ideally, the microbial cells in the MFC will transport electrons exogenously to the electrode without use of artificial mediators. ...
Microbial fuel cell (MFC) technology is an emerging area for alternative renewable energy generation and it offers additional opportunities for environmental bioremediation. Recent scientific studies have focused on MFC reactor design as well as reactor operations to increase energy output. The advancement in alternative MFC models and their performance in recent years reflect the interests of scientific community to exploit this technology for wider practical applications and environmental benefit. This is reflected in the diversity of the substrates available for use in MFCs at an economically viable level. This review provides an overview of the commonly used MFC designs and materials along with the basic operating parameters that have been developed in recent years. Still, many limitations and challenges exist for MFC development that needs to be further addressed to make them economically feasible for general use. These include continued improvements in fuel cell design and efficiency as well scale-up with economically practical applications tailored to local needs.
... Different classes of Proteobacteria, Firmicutes and Acidobacteria phyla have shown the ability of generating electrical current. Likewise, some eukaryotes such as some microalgae, yeast and fungi have also been reported growing in these systems [5]. However, the links between the microbe's identity and their electrogenic activity and, therefore, their capacity of current production and contribution to MFC performance, are barely known. ...
... As a rule, the different mechanisms proposed to explain the electron transfer to the anode in MFCs are classified depending on whether electron transfer to the electrode surface occurs through soluble compounds (mediated electron transfer) or through bacterial membrane redox active proteins and conductive pili (direct electron transfer) [5,6]. Mediated electron transfer (MET) is carried out by organic redox species of microbial origin secreted to the medium. ...
Background
Microbial fuel cells (MFCs) operating with complex microbial communities have been extensively reported in the past, and are commonly used in applications such as wastewater treatment, bioremediation or in-situ powering of environmental sensors. However, our knowledge on how the composition of the microbial community and the different types of electron transfer to the anode affect the performance of these bioelectrochemical systems is far from complete. To fill this gap of knowledge, we designed a set of three MFCs with different constrains limiting direct and mediated electron transfer to the anode. ResultsThe results obtained indicate that MFCs with a naked anode on which a biofilm was allowed unrestricted development (MFC-A) had the most diverse archaeal and bacterial community, and offered the best performance. In this MFC both, direct and mediated electron transfer, occurred simultaneously, but direct electron transfer was the predominant mechanism. Microbial fuel cells in which the anode was enclosed in a dialysis membrane and biofilm was not allowed to develop (MFC-D), had a much lower power output (about 60% lower), and a prevalence of dissolved redox species that acted as putative electron shuttles. In the anolyte of this MFC, Arcobacter and Methanosaeta were the prevalent bacteria and archaea respectively. In the third MFC, in which the anode had been covered by a cation selective nafion membrane (MFC-N), power output decreased a further 5% (95% less than MFC-A). In this MFC, conventional organic electron shuttles could not operate and the low power output obtained was presumably attributed to fermentation end-products produced by some of the organisms present in the anolyte, probably Pseudomonas or Methanosaeta. Conclusion
Electron transfer mechanisms have an impact on the development of different microbial communities and in turn on MFC performance. Although a stable current was achieved in all cases, direct electron transfer MFC showed the best performance concluding that biofilms are the major contributors to current production in MFCs. Characterization of the complex microbial assemblages in these systems may help us to unveil new electrogenic microorganisms and improve our understanding on their role to the functioning of MFCs.
... Examples of such certain genes reported as redox-active compounds (e.g., pyocyanin), outer membrane multiheme cytochromes (e.g. OmcZ), conductive pili predominantly in the members of Shewanellaceae and Geobacteraceae family (Kumar et al., 2015). Whereas, Pseudomonas aeruginosa, Bacillus subtilis, Aeromonas hydrophila subsp. ...
The microbial fuel cell (MFC) was constructed from polypropylene random (PP-R) pipes jointed in U-shaped manner with a cation exchange membrane. The MFC constructed was subjected for the bioelectricity production by using vegetable waste extract as substrate. The power production was analyzed for three days. Maximum power density of 88990mW/m² with a current density of 314.4mA/m² was observed on the second day of process with minimum internal resistance comparatively i.e. 123.23. The higher power density shows effciency of this U-shaped design compare to other dual chamber MFCs.
