Microbial-anode fuel cells (MAFCs) with high electron recovery (> 50%) from acetate and glucose have been constructed in this study. By inoculating fresh sedimentary microorganisms into anaerobic anode compartments, a stable current (similar to 0.42 mA for acetate-fed MAFCs; similar to 0.35 mA for glucose-fed MAFCs) is generated from the oxidation of the added organic matter until its concentration decreases to a low level. SEM micrographs indicate that thick biofilms of microbial communities (coccoid cells with a diameter of similar to 0.5 mu m in acetate-fed MAFCs; rod-shaped cells with a length of 2.0-4.0 mu m and a width of 0.5-0.7 mu m in glucose-fed MAFCs) completely cover the anode electrodes. These anodophillic, biofilms are thought to be responsible for the current generation, and make these microbial-anode fuel cells exhibit good performance even when the growth medium is replaced by a salt buffer without any growth factor. In comparison with those microbial fuel cells that require the addition of artificial electron transfer-mediating compounds, the findings in this study imply a potential way to develop excellent mediator-less MAFCs for electricity generation from organic matter by using substrate-induced anodophillic microbial species. (c) 2006 Elsevier B.V. All rights reserved.