title: The biocathode of microbial electrochemical systems and microbially-influenced corrosion.
abstract: The cathode reaction is one of the most important limiting factors in bioelectrochemical systems even with precious metal catalysts. Since aerobic bacteria have a much higher affinity for oxygen than any known abiotic cathode catalysts, the performance of a microbial fuel cell can be improved through the use of electrochemically-active oxygen-reducing bacteria acting as the cathode catalyst. These consume electrons available from the electrode to reduce the electron acceptors present, probably conserving energy for growth. Anaerobic bacteria reduce protons to hydrogen in microbial electrolysis cells (MECs). These aerobic and anaerobic bacterial activities resemble those catalyzing microbially-influenced corrosion (MIC). Sulfate-reducing bacteria and homoacetogens have been identified in MEC biocathodes. For sustainable operation, microbes in a biocathode should conserve energy during such electron-consuming reactions probably by similar mechanisms as those occurring in MIC. A novel hypothesis is proposed here which explains how energy can be conserved by microbes in MEC biocathodes.
authors.affiliation: Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Malaysia; School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin, Heilongjiang Province 150090, China; Korea Institute of Science and Technology, Seongbuk-ku, Seoul 136-791, Republic of Korea.
authors.forename: Byung Hong
authors.initials: BH
authors.lastname: Kim
authors.affiliation: Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Malaysia; School of Chemical Engineering and Advanced Materials, Merz Court, Newcastle University, Newcastle-upon-Tyne, NE1 7RU, UK. Electronic address: limss@ukm.edu.my.
authors.forename: Swee Su
authors.initials: SS
authors.lastname: Lim
authors.affiliation: Fuel Cell Institute, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Malaysia; Department of Chemical and Process Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Malaysia.
authors.forename: Wan Ramli Wan
authors.initials: WR
authors.lastname: Daud
authors.affiliation: Geomicrobiology Group, College of Life Sciences, University of Dundee, Dundee, DD1 5EH, Scotland, UK; Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, China.
authors.forename: Geoffrey Michael
authors.initials: GM
authors.lastname: Gadd
authors.affiliation: School of Environmental Science and Engineering, Gwangju Institute of Science and Technology, 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712, Republic of Korea.
authors.forename: In Seop
authors.initials: IS
authors.lastname: Chang
mesh_terms: D018407:Bacterial Physiological Phenomena; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D003343:Corrosion; D004563:Electrochemistry / Q000295:instrumentation*; D004566:Electrodes / Q000382:microbiology*; D004735:Energy Transfer / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008954:Models, Biological
keywords: Biocathode; Bioelectrochemical systems; Energy conservation; Microbial electrolysis cells; Microbially-influenced corrosion