Bacterial DGGE fingerprints of biofilms on electrodes of membraneless microbial fuel cells

► Biofilm analysed by DGGE (Denaturing Gradient Gel Electrophoresis). ► Air cathode single-chamber membraneless microbial fuel cells were used. ► Anodic communities did not differ significantly from cathodic at the test end. ► Spirochetes, Purple Non-Sulfur (PNS), Sulfate-reducing Bacteria (SRB) were found. ► A possible central role of SRB metabolism at cathode was discussed and underlined.