Physical features of carbonaceous materials are more important than chemical composition to attain high efficiencies. For use as anode in MFC, carbon felt overcomes other carbonaceous materials such as cloth or foam. Stainless steel cathodes are less efficient than carbon felt cathodes and can limit the performance of MFC. Maximum power produced using carbon felt anode/cathode is around 1 W m− 2 feeding 5000 mg dm− 3 of acetate.