DSA to grow electrochemically active biofilms of Geobacter sulfurreducens

Claire Dumas (1) , Régine Basséguy (1) , Alain Bergel (1)

1 LGC - Laboratoire de Génie Chimique

Biofilms of Geobacter sulfurreducens were grown on graphite and on dimensionally stable anodes (DSA) in medium that did not contain any soluble electron acceptor. Several working electrodes were individually addressed and placed in the same reactor to compare their electrochemical behaviour in exactly the same biochemical conditions. Under constant polarization at 0.20Vversus Ag/AgCl, the electrodes were able progressively to oxidize acetate (5 mM), and average current densities around 5Am−2 and 8Am−2 were sustained for days on DSA and graphite, respectively. Removing the biofilm from the electrodes led the current to zero, while changing the medium by fresh one did not disturb the current when contact to air was avoided. This confirmed that the biofilm was fully responsible for the electro-catalysis of acetate oxidation and the current was not due to the accumulation of compounds in the bulk. Cyclic voltammetries performed during chronoamperometry indicated that the oxidation started above 0.05V versus Ag/AgCl. The difference in maximal current values obtained with DSA and graphite was not linked to the biofilm coverage ratios, which were of the same order of magnitude in the range of 62–78%. On the contrary, the difference in maximal current values matched the ratio of the average surface roughness of the materials, 5.6 m and 3.2 m for graphite and DSA, respectively.

Mots clés: Electroactive biofilm; Geobacter sulfurreducens; Dimensionally stable anode (DSA); Surface roughness; Microbial fuel cell (MFC)

Domaines: Génie chimique

Claire Dumas, Régine Basséguy, Alain Bergel. DSA to grow electrochemically active biofilms of Geobacter sulfurreducens. Electrochimica Acta, 2007, Vol. 53 N° 7., 3200-3209 available on : http://oatao.univ-toulouse.fr/22/1/basseguy_22.pdf. ⟨10.1016/j.electacta.2007.10.066⟩. ⟨hal-00467123⟩