In this study, azo dye adapted mixed microbial consortium was used to effectively remove colour from azo dye mixtures and to simultaneously generate bio-electricity using microbial fuel cells (MFCs). Operating temperature (20-50 degrees C) and salinity (0.5-2.5% w/v) were varied during experiments. Reactor operation at 50 degrees C improved dye decolourisation and COD removal kinetic constants by approximately 2-fold compared to the kinetic constants at 30 degrees C. Decolourisation and COD removal kinetic constants remained high (0.28 h(-1) and 0.064 h(-1) respectively) at moderate salinity (1% w/v) but deteriorated approximately 4-fold when the salinity was raised to 2.5% (w/v). Molecular phylogenetic analysis of microbial cultures used in the study indicated that both un-acclimated and dye acclimated cultures from MFCs were predominantly comprised of Firmicutes bacteria. This study demonstrates the possibility of using adapted microbial consortia in MFCs for achieving efficient bio-decolourisation of complex azo dye mixtures and concomitant bio-electricity generation under industrially relevant conditions. (C) 2012 Elsevier Ltd. All rights reserved.