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Anodophilic biofilm catalyzes cathodic oxygen reduction.
Environ Sci Technol. 2010 Jan 01; 44(1):518-25.ES

Abstract

Poor cathodic oxygen reduction and the detrimental buildup of a pH gradient between anode and cathode are the major hurdles in the development of sustainable microbial fuel cells (MFCs). This article describes and tests a concept that can help overcoming both of these limitations, by inverting the polarity of the MFC repeatedly, allowing anodic and cathodic reactions to occur alternately in the same half-cell and hence neutralizing its respective pH effects. For simplicity, we studied polarity inversion exclusively in one half-cell, maintaining its potential at -300 mV (vs Ag/AgCl) by a potentiostat. An alternating supply of acetate and dissolved oxygen to the biofilm resulted in the tested half-cell repeatedly changing from an anode to a cathode and vice versa. This repeated inversion of current direction avoided the detrimental drifting of the electrolyte pH. Control runs without current inversion ceased to produce current, as a result of anode acidification. The presence of the anodophilic biofilm survived the intermittent oxygen exposure and could measurably facilitate the cathodic reaction by reducing the apparent oxygen overpotential. It enabled cathodic oxygen reduction at about -150 mV (vs Ag/AgCl) compared to -300 mV (vs Ag/AgCl) for the same electrode material (granular graphite) without biofilm. Provided that a suitable cathodic potential was chosen, the presence of "anodophilic bacteria" at the cathode could enable a 5-fold increase in power output. Overall, the ability of an electrochemically active biofilm to catalyze both substrate oxidation and cathodic oxygen reduction in a single bioelectrochemical system has been documented. This property could be useful to alleviate both the cathodic oxygen reduction and the detrimental drifting of electrolyte pH in an MFC system. Further research is warranted to explore the application of such bidirectional microbial catalytic properties for sustainable MFC processes.

Authors+Show Affiliations

Faculty of Sustainability, Environmental and Life Science, Murdoch University, WA 6150, Australia. k.cheng@murdoch.edu.auNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

19954225

Citation

Cheng, Ka Yu, et al. "Anodophilic Biofilm Catalyzes Cathodic Oxygen Reduction." Environmental Science & Technology, vol. 44, no. 1, 2010, pp. 518-25.
Cheng KY, Ho G, Cord-Ruwisch R. Anodophilic biofilm catalyzes cathodic oxygen reduction. Environ Sci Technol. 2010;44(1):518-25.
Cheng, K. Y., Ho, G., & Cord-Ruwisch, R. (2010). Anodophilic biofilm catalyzes cathodic oxygen reduction. Environmental Science & Technology, 44(1), 518-25. https://doi.org/10.1021/es9023833
Cheng KY, Ho G, Cord-Ruwisch R. Anodophilic Biofilm Catalyzes Cathodic Oxygen Reduction. Environ Sci Technol. 2010 Jan 1;44(1):518-25. PubMed PMID: 19954225.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Anodophilic biofilm catalyzes cathodic oxygen reduction. AU - Cheng,Ka Yu, AU - Ho,Goen, AU - Cord-Ruwisch,Ralf, PY - 2009/12/4/entrez PY - 2009/12/4/pubmed PY - 2010/3/26/medline SP - 518 EP - 25 JF - Environmental science & technology JO - Environ Sci Technol VL - 44 IS - 1 N2 - Poor cathodic oxygen reduction and the detrimental buildup of a pH gradient between anode and cathode are the major hurdles in the development of sustainable microbial fuel cells (MFCs). This article describes and tests a concept that can help overcoming both of these limitations, by inverting the polarity of the MFC repeatedly, allowing anodic and cathodic reactions to occur alternately in the same half-cell and hence neutralizing its respective pH effects. For simplicity, we studied polarity inversion exclusively in one half-cell, maintaining its potential at -300 mV (vs Ag/AgCl) by a potentiostat. An alternating supply of acetate and dissolved oxygen to the biofilm resulted in the tested half-cell repeatedly changing from an anode to a cathode and vice versa. This repeated inversion of current direction avoided the detrimental drifting of the electrolyte pH. Control runs without current inversion ceased to produce current, as a result of anode acidification. The presence of the anodophilic biofilm survived the intermittent oxygen exposure and could measurably facilitate the cathodic reaction by reducing the apparent oxygen overpotential. It enabled cathodic oxygen reduction at about -150 mV (vs Ag/AgCl) compared to -300 mV (vs Ag/AgCl) for the same electrode material (granular graphite) without biofilm. Provided that a suitable cathodic potential was chosen, the presence of "anodophilic bacteria" at the cathode could enable a 5-fold increase in power output. Overall, the ability of an electrochemically active biofilm to catalyze both substrate oxidation and cathodic oxygen reduction in a single bioelectrochemical system has been documented. This property could be useful to alleviate both the cathodic oxygen reduction and the detrimental drifting of electrolyte pH in an MFC system. Further research is warranted to explore the application of such bidirectional microbial catalytic properties for sustainable MFC processes. SN - 0013-936X UR - https://www.unboundmedicine.com/medline/citation/19954225/Anodophilic_biofilm_catalyzes_cathodic_oxygen_reduction_ L2 - https://doi.org/10.1021/es9023833 DB - PRIME DP - Unbound Medicine ER -
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