Electroactive biofilms of sulphate reducing bacteria

Biofilms formed from a pure strain of Desulfovibrio desulfuricans 27774 on stainless steel and graphite polarised surfaces were studied. The polarisation conditions applied were -0.4V vs. SCE for different times. A cathodic current related with the biofilms growth was observed with a maximum intensity of -270 mA m(-2) that remained stable for several days using graphite electrodes. These sulphate reducing bacteria biofilms present electrocatalytic activity towards hydrogen and oxygen reduction reactions. Electrode polarisation has a selective effect on the catalytic activity. The biofilms were also observed by scanning electronic microscopy revealing the formation of homogeneous films on the surfaces. (c) 2008 Elsevier Ltd. All rights reserved.