Direct generation of electricity from a mixture of carbon sources was examined using single chamber mediator-less air cathode microbial fuel cells (MFCs) at sub-ambient temperatures. Electricity was directly generated from a carbon source mixture of D-glucose, D-galactose, D-xylose, D-glucuronic acid and sodium acetate at 30 degrees C and <20 degrees C (down to 4 degrees C). Anodic biofilms enriched at different temperatures using carbon source mixtures were examined using epi-fluorescent, scanning electron microscopy, and cyclic voltammetry for electrochemical evaluation. The maximum power density obtained at different temperatures ranged from 486 +/- 68 mW m(-2) to 602 +/- 38mW m(-2) at current density range of 0.31 mA cm(-2) to 0.41 mA cm(-2) (14 degrees C and 30 degrees C, respectively). Coulombic efficiency increased with decreasing temperature, and ranged from 24 +/- 3 to 38 +/- 1% (20 degrees C and 4 degrees C, respectively). Chemical oxygen demand (COD) removal was over 68% for all carbon sources tested. Our results demonstrate adaptation, by gradual increase of cold-stress, to electricity production in MFCs at sub-ambient temperatures. (C) 2010 Elsevier B.V. All rights reserved.