The terms "bioelectrochemical systems (BESs)" include all devices able to transform chemical energy into electrical energy by the action of microorganisms. Those last belong to a specific community called electroactive bacteria (EAB). Organized in biofilm at the surface of a solid electrode, EAB are able to exchange electrons with conductive surfaces. Thanks to their unique extracellular transfer system, the first electroactive bacterial species discovered, as Geobacter metallireducens, were able to use iron or manganese oxides, naturally present in their environment, as the terminal electron acceptor in their metabolism process. Em-ployed in an electrochemical cell, EAB acted as catalysts of the redox reactions. Since 2008, the research team L3MA worked on a particular BES which is microbial fuel cell (MFC). Via an electrical circuit connected to the cell, MFC harvests the electrons from the biodegrada-tion of a fuel (organic compounds, ligno-cellulosic biomasses for examples). The main ad-vantage of MFC lies in the generation of electricity that could be combined with bioremedia-tion (COD, metal, pollutant removals). L3MA has demonstrated that mangrove is source of EAB. Indeed, mangrove environment has the physicochemical characteristics required to be sources of EAB: sedimentary soils, high temperature and high salinity. The objective of L3MA studies was to improve knowledge on mangrove EAB and their role in MFCs. Electrochemical and biological results were facing. The influence of a fuel supply (acetate) and the presence of an electrical connection of the bacterial biofilm support were evaluated. The maximal power of the MFCs, measured in a stable plate of electrical activity following an ace-tate addition as substrate, was 450 mW/m2 of projected anode surface. The anodic potential switched from 400 mV to -400 mV during period without acetate and with acetate respectively. The formation of the anodic biofilm seems to be essentially influenced by the sediment with a similar diversity of bacterial community. The proteobacteria phylum dominated the ecosys-tem and was mostly composed by two genera: Sulfurimonas sp. and Desulfobacter sp.