Bidirectional microbial electron transfer: Switching an acetate oxidizing biofilm to nitrate reducing conditions

Pous, Narcís; Carmona-Martínez, Alessandro A.; Vilajeliu-Pons, Anna; Fiset, Erika; Bañeras, Lluís; Trably, Eric; Balaguer, M. Dolors; Colprim, Jesús; Bernet, Nicolas; Puig, Sebastià

doi:10.1016/j.bios.2015.08.035

Cited by 87 publications

(44 citation statements)

References 52 publications

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“…Then, the circulation pumps were turned on and the cathode polarization was posed at +150 mV vs. SCE for 7 days to enhance biocathode inoculation. On the eighth day, the polarization was changed to −550 mV vs. SCE to enhance the denitrification, as has been proven to work in previous articles [37].…”

Section: Operating Conditionsmentioning

confidence: 97%

Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study

Lust

Nerut

Kasak

et al. 2020

Water

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Assessments of groundwater aquifers made around the world show that in many cases, nitrate concentrations exceed the safe drinking water threshold. This study assessed how bioelectrochemical systems could be used to enhance nitrate removal from waters with low organic carbon concentrations. A two-chamber microbial electrosynthesis cell (MES) was constructed and operated for 45 days with inoculum that was taken from a municipal wastewater treatment plant. A study showed that MES can be used to enhance nitrate removal efficiency from 3.66% day−1 in a control reactor to 8.54% day−1 in the MES reactor, if a cathode is able to act as an electron donor for autotrophic denitrifying bacteria or there is reducing oxygen in a cathodic chamber to favor denitrification. In the MES, greenhouse gas emissions were also lower compared to the control. Nitrous oxide average fluxes were −639.59 and −9.15 µg N m−2 h−1 for the MES and control, respectively, and the average carbon dioxide fluxes were −5.28 and 43.80 mg C m−2 h−1, respectively. The current density correlated significantly with the dissolved oxygen concentration, indicating that it is essential to keep the dissolved oxygen concentration in the cathode chamber as low as possible, not only to suppress oxygen’s inhibiting effect on denitrification but also to achieve better power efficiency.

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Section: Operating Conditionsmentioning

confidence: 97%

Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study

Lust

Nerut

Kasak

et al. 2020

Water

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“…To accurately identify the biocatalytic active sites responsible for electricity generation, biofilms were analyzed by non-turnover CV and turnover DPV ( Pous et al, 2016 ). As shown in Figures 2A,B , both biofilms demonstrated two major redox species with formal potentials of -0.38 V ( E 2 ) and -0.31 V ( E 3 ) and a minor redox species with a formal potential of -0.42 V ( E 1 ).…”

Section: Resultsmentioning

confidence: 99%

Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors

et al. 2018

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The ability of Geobacter species to transfer electrons outside cells enables them to play an important role in biogeochemical and bioenergy processes. Our knowledge of the extracellular electron transfer (EET) process in the genus Geobacter is mainly from the study of G. sulfurreducens, and in order to fully investigate the EET mechanisms in the genus Geobacter, other Geobacter species should also be considered. This study focused on the EET of Geobacter soli GSS01, which exhibited a capability of reducing insoluble Fe(III) oxides and generating electrical current comparable with G. sulfurreducens PCA. Electrochemical characterization, including cyclic voltammetry, differential pulse voltammetry, and electrochemical in situ FTIR spectra, revealed that different redox proteins contributed to the electrochemical behaviors of G. soli and G. sulfurreducens. Based on comparative transcriptomic and proteomic analyses, OmcS was the most upregulated protein in both G. soli and G. sulfurreducens cells grown with insoluble Fe(III) oxides vs. soluble electron acceptor. However, the proteins including OmcE and PilA that were previously reported as being important for EET in G. sulfurreducens were downregulated or unchanged in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, and many proteins that were upregulated in G. soli cells grown with insoluble electron acceptors vs. soluble electron acceptor, such as OmcN, are not important for EET in G. sulfurreducens. We also identified 30 differentially expressed small RNAs (sRNAs) in G. soli cells grown with different acceptors. Taken together, these findings help to understand the versatile EET mechanisms that exist in the genus Geobacter and point to the possibility of sRNA in modulating EET gene expression.

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“…It is also advantageous to use a microbiosensor rather than a macroscale sensor to monitor acetate concentrations in bulk solutions because the small size of the electrode tip provides faster response times, lower detection limits and higher resolutions than a large electrode (Beyenal and Babauta, 2014). The developed microbiosensor can be modified for electron acceptors such as nitrate and fumarate since G. sulfurreducens biofilms can reduce nitrate and fumarate when a solid electrode is used as an electron donor (Choi and Sang, 2016; Gregory et al, 2004; Pous et al, 2016). To achieve this, the operation of the microbiosensor should be switched to a cathodic mode by setting an appropriate potential.…”

Section: Resultsmentioning

confidence: 99%

Microbiosensor for the detection of acetate in electrode-respiring biofilms

Atçı

Babauta

Sultana

et al. 2016

Biosensors and Bioelectronics

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The goal of this work was to develop a microbiosensor to measure acetate concentration profiles inside biofilms in situ. The working principle of the microbiosensor was based on the correlation between the acetate concentration and the current generated during acetate oxidation by Geobacter sulfurreducens. The microbiosensor consisted of a 30-μm carbon microelectrode with an open tip as a working electrode, with G. sulfurreducens biofilm on the tip and a pseudo Ag/AgCl reference electrode, all enclosed in a glass outer case with a 30-μm tip diameter. The microbiosensor showed a linear response in the 0–1.6 mM acetate concentration range with a 79 ± 8 μM limit of detection (S/N=2). We quantified the stirring effect and found it negligible. However, the interfering effect of alternative electron donors (lactate, formate, pyruvate, or hydrogen) was found to be significant. The usefulness of the acetate microbiosensor was demonstrated by measuring acetate concentration depth profiles within a G. sulfurreducens biofilm. The acetate concentration remained at bulk values throughout the biofilm when no current was passed, but it decreased from the bulk values to below the detection limit within 200 μm when current was allowed to pass. The zero acetate concentration at the bottom of the biofilm showed that the biofilm was acetate-limited.

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Bidirectional microbial electron transfer: Switching an acetate oxidizing biofilm to nitrate reducing conditions

Cited by 87 publications

References 52 publications

Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study

Enhancing Nitrate Removal from Waters with Low Organic Carbon Concentration Using a Bioelectrochemical System—A Pilot-Scale Study

Transcriptomic, Proteomic, and Bioelectrochemical Characterization of an Exoelectrogen Geobacter soli Grown With Different Electron Acceptors

Microbiosensor for the detection of acetate in electrode-respiring biofilms

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