Oxygen exposure promotes fuel diversity for Shewanella oneidensis microbial fuel cells

Biffinger, Justin C.; Byrd, Jacqueline N.; Dudley, Breanna L.; Ringeisen, Bradley R.

doi:10.1016/j.bios.2007.08.021

Cited by 155 publications

(76 citation statements)

References 37 publications

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“…The measurement atmosphere was precisely adjusted between strict anaerobic to microaerophilic conditions by tuning the ratio of pure O 2 and N 2 gas sources (0-10%) using mass flow controllers. As described previously, the largest current values were observed for a nonagitated, air-exposed condition (20,21).…”

Section: Methodssupporting

confidence: 77%

Probing electron transfer mechanisms in Shewanella oneidensis MR-1 using a nanoelectrode platform and single-cell imaging

Jiang

Fitzgerald

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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140

101

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Microbial fuel cells (MFCs) represent a promising approach for sustainable energy production as they generate electricity directly from metabolism of organic substrates without the need for catalysts. However, the mechanisms of electron transfer between microbes and electrodes, which could ultimately limit power extraction, remain controversial. Here we demonstrate optically transparent nanoelectrodes as a platform to investigate extracellular electron transfer in Shewanella oneidensis MR-1, where an array of nanoholes precludes or single window allows for direct microbeelectrode contacts. Following addition of cells, short-circuit current measurements showed similar amplitude and temporal response for both electrode configurations, while in situ optical imaging demonstrates that the measured currents were uncorrelated with the cell number on the electrodes. High-resolution imaging showed the presence of thin, 4-to 5-nm diameter filaments emanating from cell bodies, although these filaments do not appear correlated with current generation. Both types of electrodes yielded similar currents at longer times in dense cell layers and exhibited a rapid drop in current upon removal of diffusible mediators. Reintroduction of the original cell-free media yielded a rapid increase in current to ∼80% of original level, whereas imaging showed that the positions of >70% of cells remained unchanged during solution exchange. Together, these measurements show that electron transfer occurs predominantly by mediated mechanism in this model system. Last, simultaneous measurements of current and cell positions showed that cell motility and electron transfer were inversely correlated. The ability to control and image cell/electrode interactions down to the single-cell level provide a powerful approach for advancing our fundamental understanding of MFCs.bacteria | bioenergy | nanostructure | electron shuttles | nanowires

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Section: Methodssupporting

confidence: 77%

Probing electron transfer mechanisms in Shewanella oneidensis MR-1 using a nanoelectrode platform and single-cell imaging

Jiang

Fitzgerald

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

140

101

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“…anodic current production during phase 1 (SI, Figure S2a), probably due to the higher energy obtained by MR-1 during complete lactate oxidation under aerated conditions 34,35 . A thicker biofilm that could be visually observed in this instance and a presumably higher production of redox mediators which exhibited (anodic) current onsets at potentials similar to the midpoint potentials of flavins 22 ( Figure S3), are also possible reasons for this enhanced performance.…”

Section: Effect Of Mr-1 Pre-treatment Conditions On Biocathode Performentioning

confidence: 99%

Enhanced Performance of Hexavalent Chromium Reducing Cathodes in the Presence ofShewanella oneidensisMR-1 and Lactate

Xafenias

Zhang

Banks

2013

Environ. Sci. Technol.

136

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Biocathodes for the reduction of the highly toxic hexavalent chromium (Cr(VI)) were investigated using Shewanella oneidensis MR-1 (MR-1) as a bio-catalyst and performance was assessed in terms of current production and Cr(VI) reduction. Potentiostatically controlled experiments (-500 mV vs. Ag/AgCl) showed that a mediatorless MR-1 biocathode started up 2 under aerated conditions in the presence of lactate, received 5.5 and 1.7 times more electrons for Cr(VI) reduction over a 4-hour operating period than controls without lactate and with lactate but without MR-1, respectively. Cr(VI) reduction was also enhanced, with a decrease in concentration over the 4-h operating period of 9 mg/L Cr(VI), compared to only 1 and 3 mg/L respectively in the controls. Riboflavin, an electron shuttle mediator naturally produced by MR-1, was also found to have a positive impact in potentiostatically controlled cathodes. Additionally, a microbial fuel cell (MFC) with MR-1 and lactate present in both anode and cathode produced a maximum current density of 32.5 mA/m 2 (1,000 Ω external load) after receiving a 10 mg/L Cr(VI) addition in the cathode, and cathodic efficiency increased steadily over an 8-day operation period with successive Cr(VI) additions. In conclusion, effective and continuous Cr(VI) reduction with associated current production were achieved when MR-1 and lactate were both present in the biocathodes. INTRODUCTIONHexavalent chromium (Cr(VI)) is a highly toxic, mutagenic and carcinogenic substance that is present in the effluent streams of a wide range of industrial processes, including electroplating, leather tanning and wood preserving 1 . It is highly soluble and, because of its long history of use and often its disposal after inappropriate or no treatment, it has become one of the most abundant inorganic contaminants in groundwater. Ideally Cr(VI) should be removed from groundwater in the natural environment, and because of the inherent dangers to health the stringent guideline limit of 50 μg/L has been issued for total chromium concentration in drinking water 1,2 . Removal options include ion-exchange, adsorption and electrodialysis 3 ; however in many of these applications chromium keeps its toxic hexavalent state. Reduction of Cr(VI) to the considerably 3 less toxic trivalent form Cr(III) and its subsequent precipitation at neutral pH could be considered a more effective remediation strategy 4 .A possible method for Cr(VI) reduction using a microbial fuel cell (MFC) has recently been proposed, where Cr(VI) was used as an oxidant in the cathode to generate an electrical energy output 5,6 . At low pH values where H + is abundant, cathodic Cr(VI) reduction has been demonstrated at relatively fast rates and without the use of a catalyst 5,6 . In the neutral pH region, however, the reaction kinetics are slower due to low H + availability:CrO 4 2-+ 8H + + 3e -= Cr 3+ + 4H 2 O (1) At neutral pH, Cr(VI) reduction takes place under lower cathode potentials and is also severely inhibited by Cr(III) oxyhydroxide monolayers w...

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“…The Coulombic efficiency (Ce) was calculated as Ce = M 9 I/F 9 n 9 q 9 DCOD, where M is the molecular weight of oxygen, I is the current, F is Faraday's constant, n is the number of electrons exchanged per mole of oxygen, q is the volumetric influent flow rate, and DCOD is the difference in the influent and the effluent COD. For the theoretical Coulombic amount calculations, four moles of electrons (n = 4) were produced per mole of COD in synthetic wastewater (Biffinger et al 2008;Lee et al 2008;Behera and Ghangrekar 2009;Rodrigo et al 2009;Sun et al 2009). …”

Section: Analyses Of Water Quality and Power Generationmentioning

confidence: 99%

Effects of flow rate and chemical oxygen demand removal characteristics on power generation performance of microbial fuel cells

Juang¹,

Yang²,

Kuo³

2012

Int. J. Environ. Sci. Technol.

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Two microbial fuel cells with different oxygen supplies in the cathodic chamber were constructed. Electrogenic capabilities of both cells were compared under the same operational conditions. Results showed that binary quadratic equations can express the relationships between chemical oxygen demand degradation rate and chemical oxygen demand loading and between chemical oxygen demand removal rate and chemical oxygen demand loading in both cells. Good linear relationships between power output (voltage or power density) and flow rate and between power output and chemical oxygen demand degradation rate were only found on the cell with mechanical aeration in the cathodic chamber, but not on the cell with algal photosynthesis in the cathodic chamber. The relationships between power output and chemical oxygen demand removal rate and between power output and effluent chemical oxygen demand concentration on both cells can be expressed as binary quadratic equations. The optimum flow rates to obtain higher power density and higher Coulombic efficiency in the cell with mechanical aeration in the cathodic chamber (=0.85 mW/m 2 and 0.063%) and in the cell with algal photosynthesis in the cathodic chamber (=0.65 mW/m 2 and 0.05%) are about 1000 and 1460 lL/min, respectively. The optimum chemical oxygen demand removal rates to obtain higher power density and higher Coulombic efficiency in the cell with mechanical aeration in the cathodic chamber (=1.2 mW/m 2 and 0.064%) and in the cell with algal photosynthesis in the cathodic chamber (=0.81 mW/m 2 and 0.051%) are about 40.5 and 36.5%, respectively.

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Oxygen exposure promotes fuel diversity for Shewanella oneidensis microbial fuel cells

Cited by 155 publications

References 37 publications

Probing electron transfer mechanisms in Shewanella oneidensis MR-1 using a nanoelectrode platform and single-cell imaging

Probing electron transfer mechanisms in Shewanella oneidensis MR-1 using a nanoelectrode platform and single-cell imaging

Enhanced Performance of Hexavalent Chromium Reducing Cathodes in the Presence ofShewanella oneidensisMR-1 and Lactate

Effects of flow rate and chemical oxygen demand removal characteristics on power generation performance of microbial fuel cells

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