FROM “OMICS” TO “OHMICS”: ELECTRICITYPRODUCING BACTERIAL COMMUNITY STRUCTURES IN MICROBIAL FUEL CELLS

Abstract

International audienceMicrobial Fuel Cells (MFCs) are being developed as a novel biotechnology to harvest energy from dissolved organic matter with potential applications ranging from wastewater treatment to power sources for remote environmental sensors. To date, there is limited information about the structure of electro-active bacterial communities, and in order to optimize energy production in MFCs, a better understanding of these communities is essential. Our objective was to determine the taxonomic structure and spatial organization of the bacterial communities present at the surface of the electrodes during the formation and development of electro-active biofilms. Experiments were performed using single chamber MFCs fed with primary clarifier effluent from a municipal wastewater treatment plant. Community structure analyses were performed as a function of time and electrical performances using a combination of molecular tools (metagenomic DNA extraction, 16S-rRNA-based phylogenetic microarrays, pyrosequencing...). Analyses of the biofilm structure, distribution and physiological state of the bacterial cells at the surface of the electrodes were performed using a range of fluorochromes and epifluorescence microscopy equipped with a 3D imaging system. Metagenomic approaches helped us to identify putative bacterial species and genes involved in electricity production in MFCs. In combination with image analyses, data obtained strongly supports the possibility of increasing electrical performances by modifying electrode design, feeding and microbial growth conditions in MFCs