title: Halotolerant bioanodes: The applied potential modulates the electrochemical characteristics, the biofilm structure and the ratio of the two dominant genera.
abstract: The development of economically-efficient microbial electrochemical technologies remains hindered by the low ionic conductivity of the culture media used as the electrolyte. To overcome this drawback, halotolerant bioanodes were designed with salt marsh sediment used as the inoculum in electrolytes containing NaCl at 30 or 45g/L (ionic conductivity 7.0 or 10.4S·m(-1)). The bioanodes were formed at four different potentials -0.4, -0.2, 0.0 and 0.2V/SCE to identify the effect on the electrochemical kinetic parameters, the biofilm structures and the composition of the microbial communities. The bioanodes formed at -0.4V/SCE were largely dominated by Marinobacter spp. Voltammetry showed that they provided higher currents than the other bioanodes in the range of low potentials, but the maximum currents were limited by the poor surface colonization. The bioanodes formed at -0.2, 0.0 and 0.2V/SCE showed similar ratios of Marinobacter and Desulfuromonas spp. and higher values of the maximum current density. The combined analysis of kinetic parameters, biofilm structure and biofilm composition showed that Marinobacter spp., which ensured a higher electron transfer rate, were promising species for the design of halotolerant bioanodes. The challenge is now to overcome its limited surface colonization in the absence of Desulfuromonas spp.
authors.affiliation: Laboratoire de Génie Chimique, CNRS-Université de Toulouse (INPT), 4 allée Emile Monso, BP 84234, 31432 Toulouse, France.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Rousseau
authors.affiliation: Laboratoire d'Ecologie Microbienne de la Rhizosphere & Environnement Extrêmes (LEMiRE), UMR 7265, CNRS-CEA-Aix-Marseille, Université, CEA Cadarache DSV/IBEB/SBVME, 13108 Saint Paul lez Durance, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Santaella
authors.affiliation: INRA UR 0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, F-11100 Narbonne, France.
authors.forename: Anaïs
authors.initials: A
authors.lastname: Bonnafous
authors.affiliation: Laboratoire d'Ecologie Microbienne de la Rhizosphere & Environnement Extrêmes (LEMiRE), UMR 7265, CNRS-CEA-Aix-Marseille, Université, CEA Cadarache DSV/IBEB/SBVME, 13108 Saint Paul lez Durance, France.
authors.forename: Wafa
authors.initials: W
authors.lastname: Achouak
authors.affiliation: INRA UR 0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, F-11100 Narbonne, France.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Godon
authors.affiliation: Laboratoire de Génie Chimique, CNRS-Université de Toulouse (INPT), 4 allée Emile Monso, BP 84234, 31432 Toulouse, France.
authors.forename: Marie-Line
authors.initials: ML
authors.lastname: Delia
authors.affiliation: Laboratoire de Génie Chimique, CNRS-Université de Toulouse (INPT), 4 allée Emile Monso, BP 84234, 31432 Toulouse, France. Electronic address: alain.bergel@ensiacet.fr.
authors.forename: Alain
authors.initials: A
authors.lastname: Bergel
mesh_terms: D001674:Bioelectric Energy Sources / Q000382:microbiology*; D018441:Biofilms; D003343:Corrosion; D004553:Electric Conductivity; D004563:Electrochemistry; D004566:Electrodes; D020563:Gammaproteobacteria / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D007700:Kinetics
keywords: Bioelectrochemical system; Microbial anode; Microbial community; Microbial electrochemical technology; Microbial fuel cell