A microbial fuel cell capable of converting glucose to electricity at high rate and efficiency.
TL;DR: This research indicates that microbial electricity generation offers perspectives for optimization in relation to glucose dosage and five fold higher power output than reported thus far.
Abstract: A microbial fuel cell containing a mixed bacterial culture utilizing glucose as carbon source was enriched to investigate power output in relation to glucose dosage. Electron recovery in terms of electricity up to 89% occurred for glucose feeding rates in the range 0.5–3 g l−1 d−1, at powers up to 3.6 W m−2 of electrode surface, a five fold higher power output than reported thus far. This research indicates that microbial electricity generation offers perspectives for optimization.
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TL;DR: A review of the different materials and methods used to construct MFCs, techniques used to analyze system performance, and recommendations on what information to include in MFC studies and the most useful ways to present results are provided.
Abstract: Microbial fuel cell (MFC) research is a rapidly evolving field that lacks established terminology and methods for the analysis of system performance. This makes it difficult for researchers to compare devices on an equivalent basis. The construction and analysis of MFCs requires knowledge of different scientific and engineering fields, ranging from microbiology and electrochemistry to materials and environmental engineering. Describing MFC systems therefore involves an understanding of these different scientific and engineering principles. In this paper, we provide a review of the different materials and methods used to construct MFCs, techniques used to analyze system performance, and recommendations on what information to include in MFC studies and the most useful ways to present results.
5,024 citations
TL;DR: How bacteria use an anode as an electron acceptor and to what extent they generate electrical output is discussed and the MFC technology is evaluated relative to current alternatives for energy generation.
2,042 citations
Cites background or methods from "A microbial fuel cell capable of co..."
...The substrate conversion rate This depends on the amount of bacterial cells, the mixing and mass transfer phenomena in the reactor, the bacterial kinetics (mmax, the maximum specific growth rate of the bacteria, and Ks, the bacterial affinity constant for the substrate), the biomass organic loading rate (g substrate per g biomass present per day) [ 6 ], the efficiency of the proton exchange membrane for transporting protons [4,35] and the ......
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...Observed growth yields vary between 0.07 and 0.22 in glucose-fed MFCs [ 6 ]....
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...Processes using oxidative phosphorylation have regularly been observed in MFCs, yielding high energy efficiencies of up to 65% [ 6 ]....
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...Mixed consortium, batch Glucose Plain graphite 30 3600 216 [ 6 ] Activated sludge Wastewater Woven graphite 0.2 8 1.6 [10]...
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...Based on a mixed anaerobic–aerobic sludge inoculum and using glucose as feed, seven-fold increases in bacterial substrate to electricity conversion rates were observed after three months of microbial adaptation and selection [ 6 ]....
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TL;DR: An analysis based on available anode surface area and maximum bacterial growth rates suggests that mediatorless MFCs may have an upper order-of-magnitude limit in power density of 10(3) mW/m2.
Abstract: Microbial fuel cells (MFCs) are typically designed as a two-chamber system with the bacteria in the anode chamber separated from the cathode chamber by a polymeric proton exchange membrane (PEM). Most MFCs use aqueous cathodes where water is bubbled with air to provide dissolved oxygen to electrode. To increase energy output and reduce the cost of MFCs, we examined power generation in an air-cathode MFC containing carbon electrodes in the presence and absence of a polymeric proton exchange membrane (PEM). Bacteria present in domestic wastewater were used as the biocatalyst, and glucose and wastewater were tested as substrates. Power density was found to be much greater than typically reported for aqueous-cathode MFCs, reaching a maximum of 262 ± 10 mW/m2 (6.6 ± 0.3 mW/L; liquid volume) using glucose. Removing the PEM increased the maximum power density to 494 ± 21 mW/m2 (12.5 ± 0.5 mW/L). Coulombic efficiency was 40−55% with the PEM and 9−12% with the PEM removed, indicating substantial oxygen diffusion i...
1,833 citations
TL;DR: The various substrates that have been explored in MFCs so far, their resulting performance, limitations as well as future potential substrates are reviewed.
1,602 citations
Cites methods from "A microbial fuel cell capable of co..."
...Rabaey et al. (2003) re- ported that a maximum power density of 216 W/m3 was obtained from a glucose fed-batch MFC using 100 mM ferric cyanide as cathode oxidant....
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TL;DR: A critical review on the recent advances in MFC research with emphases on MFC configurations and performances is presented.
1,496 citations
Cites background from "A microbial fuel cell capable of co..."
...Higher electron recovery as electricity of up to 89% was also reported (Rabaey et al., 2003)....
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...This may be because a high feed rate promoted the growth of fermentative bacteria faster than those of the electrochemically active bacteria in a mixed culture (Moon et al., 2006; Kim et al., 2004; Rabaey et al., 2003)....
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...…cases with very high power outputs such as 7200 mW/m2, 4310 mW/m2 and 3600 mW/m2 all used ferricyanide in the cathodic chamber (Oh et al., 2004; Schroder et al., 2003; Rabaey et al., 2003, 2004), while less than 1000 mW/m2 was reported in studies using DO regardless of the electrode material....
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References
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Book•
01 Jan 1992
TL;DR: The most widely read reference in the water industry, Water Industry Reference as discussed by the authors, is a comprehensive reference tool for water analysis methods that covers all aspects of USEPA-approved water analysis.
Abstract: Set your standards with these standard methods. This is it: the most widely read publication in the water industry, your all-inclusive reference tool. This comprehensive reference covers all aspects of USEPA-approved water analysis methods. More than 400 methods - all detailed step-by-step; 8 vibrant, full-color pages of aquatic algae illustrations; Never-before-seen figures that will help users with toxicity testing and the identification of apparatus used in the methods; Over 300 superbly illustrated figures; A new analytical tool for a number of inorganic nonmetals; Improved coverage of data evaluation, sample preservation, and reagant water; And much more!
78,324 citations
TL;DR: The results suggest that the effectiveness of microbial fuel cells can be increased with organisms such as G. sulfurreducens that can attach to electrodes and remain viable for long periods of time while completely oxidizing organic substrates with quantitative transfer of electrons to an electrode.
Abstract: Previous studies have suggested that members of the Geobacteraceae can use electrodes as electron acceptors for anaerobic respiration. In order to better understand this electron transfer process for energy production, Geobacter sulfurreducens was inoculated into chambers in which a graphite electrode served as the sole electron acceptor and acetate or hydrogen was the electron donor. The electron-accepting electrodes were maintained at oxidizing potentials by connecting them to similar electrodes in oxygenated medium (fuel cells) or to potentiostats that poised electrodes at +0.2 V versus an Ag/AgCl reference electrode (poised potential). When a small inoculum of G. sulfurreducens was introduced into electrode-containing chambers, electrical current production was dependent upon oxidation of acetate to carbon dioxide and increased exponentially, indicating for the first time that electrode reduction supported the growth of this organism. When the medium was replaced with an anaerobic buffer lacking nutrients required for growth, acetate-dependent electrical current production was unaffected and cells attached to these electrodes continued to generate electrical current for weeks. This represents the first report of microbial electricity production solely by cells attached to an electrode. Electrode-attached cells completely oxidized acetate to levels below detection (<10 micro M), and hydrogen was metabolized to a threshold of 3 Pa. The rates of electron transfer to electrodes (0.21 to 1.2 micro mol of electrons/mg of protein/min) were similar to those observed for respiration with Fe(III) citrate as the electron acceptor (E(o)' =+0.37 V). The production of current in microbial fuel cell (65 mA/m(2) of electrode surface) or poised-potential (163 to 1,143 mA/m(2)) mode was greater than what has been reported for other microbial systems, even those that employed higher cell densities and electron-shuttling compounds. Since acetate was completely oxidized, the efficiency of conversion of organic electron donor to electricity was significantly higher than in previously described microbial fuel cells. These results suggest that the effectiveness of microbial fuel cells can be increased with organisms such as G. sulfurreducens that can attach to electrodes and remain viable for long periods of time while completely oxidizing organic substrates with quantitative transfer of electrons to an electrode.
2,133 citations
"A microbial fuel cell capable of co..." refers background in this paper
...A recent study (Bond & Lovley 2003) showed that Geobacter sulfurreducens was capable of transferring quantitatively the electrons provided by acetate as the sole carbon source to the electrode....
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TL;DR: A specific enrichment of microorganisms of the family Geobacteraceae is reported on energy-harvesting anodes, and it is shown that these microorganisms can conserve energy to support their growth by oxidizing organic compounds with an electrode serving as the sole electron acceptor.
Abstract: Energy in the form of electricity can be harvested from marine sediments by placing a graphite electrode (the anode) in the anoxic zone and connecting it to a graphite cathode in the overlying aerobic water. We report a specific enrichment of microorganisms of the family Geobacteraceae on energy-harvesting anodes, and we show that these microorganisms can conserve energy to support their growth by oxidizing organic compounds with an electrode serving as the sole electron acceptor. This finding not only provides a method for extracting energy from organic matter, but also suggests a strategy for promoting the bioremediation of organic contaminants in subsurface environments.
1,356 citations
"A microbial fuel cell capable of co..." refers background in this paper
...Studies by Bond et al. (2002) indicated that several existing organisms were capable of providing stable current output for biofuel cells over several days, even weeks....
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TL;DR: These results demonstrate in real marine environments a new form of power generation that uses an immense, renewable energy reservoir (sedimentary organic carbon) and has near-immediate application.
Abstract: In many marine environments, a voltage gradient exists across the water‐sediment interface resulting from sedimentary microbial activity. Here we show that a fuel cell consisting of an anode embedded in marine sediment and a cathode in overlying seawater can use this voltage gradient to generate electrical power in situ. Fuel cells of this design generated sustained power in a boat basin carved into a salt marsh near Tuckerton, New Jersey, and in the Yaquina Bay Estuary near Newport, Oregon. Retrieval and analysis of the Tuckerton fuel cell indicates that power generation results from at least two anode reactions: oxidation of sediment sulfide (a by-product of microbial oxidation of sedimentary organic carbon) and oxidation of sedimentary organic carbon catalyzed by microorganisms colonizing the anode. These results demonstrate in real marine environments a new form of power generation that uses an immense, renewable energy reservoir (sedimentary organic carbon) and has near-immediate application.
696 citations
"A microbial fuel cell capable of co..." refers background in this paper
...Interest has focused on three main types: heterotrophic (Delaney et al. 1984), photoheterotrophic (Tsujimura et al. 2001) and sediment cells (Tender et al. 2002)....
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TL;DR: The results show that the amount of electrical energy produced by microbial fuel cells can be increased 1,000-fold by incorporating electron mediators into graphite electrodes and imply that sewage sludge may contain unique electrophilic microbes that transfer electrons more readily than E. coli.
Abstract: A new one-compartment fuel cell was composed of a rubber bunged bottle with a center-inserted anode and a window-mounted cathode containing an internal, proton-permeable porcelain layer. This fuel cell design was less expensive and more practical than the conventional two-compartment system, which requires aeration and a ferricyanide solution in the cathode compartment. Three new electrodes containing bound electron mediators including a Mn(4+)-graphite anode, a neutral red (NR) covalently linked woven graphite anode, and an Fe(3+)-graphite cathode were developed that greatly enhanced electrical energy production (i.e., microbial electron transfer) over conventional graphite electrodes. The potentials of these electrodes measured by cyclic voltametry at pH 7.0 were (in volts): +0.493 (Fe(3+)-graphite); +0.15 (Mn(4+)-graphite); and -0.53 (NR-woven graphite). The maximal electrical productivities obtained with sewage sludge as the biocatalyst and using a Mn(4+)-graphite anode and a Fe(3+)-graphite cathode were 14 mA current, 0.45 V potential, 1,750 mA/m(2) current density, and 788 mW/m(2) of power density. With Escherichia coli as the biocatalyst and using a Mn(4+)-graphite anode and a Fe(3+)-graphite cathode, the maximal electrical productivities obtained were 2.6 mA current, 0.28 V potential, 325 mA/m(2) current density, and 91 mW/m(2) of power density. These results show that the amount of electrical energy produced by microbial fuel cells can be increased 1,000-fold by incorporating electron mediators into graphite electrodes. These results also imply that sewage sludge may contain unique electrophilic microbes that transfer electrons more readily than E. coli and that microbial fuel cells using the new Mn(4+)-graphite anode and Fe(3+)-graphite cathode may have commercial utility for producing low amounts of electrical power needed in remote locations.
672 citations
"A microbial fuel cell capable of co..." refers background or methods in this paper
...However, stable binding of the mediator to the electrode surface is difficult to achieve (Park & Zeikus 2003) both in terms of chemistry and costs....
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...Park & Zeikus (2003) reached power densities of about 0.7 W m−2 using a graphite electrode containing MnO2 and activated sludge fed with glucose as an inoculum....
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