This study describes the cooperative effect of the two biocatalysts Acetobacter aceti and Gluconobacter roseus for biodegradation as well as current generation. The electro activity of the biofilms of these two microorganisms was investigated by the bioelectrocatalytic oxidation of ethanol and glucose using cyclic voltammetry. Two chamber microbial fuel cells (MFCs) were constructed using single culture of A. aceti (A-MFC), and G. roseus (G-MFC) and also using mixed culture (AG-MFC). Each MFC was fed with four different substrates viz., glucose, ethanol, acetate and bad wine. AG-MFC produced higher power density with glucose (1.05 W/m(3)), ethanol (1.97 W/m(3)), acetate (1.39 W/m(3)) and bad wine (3.82 W/m(3)). COD removal (94%) was maximum for acetate fed MFCs. Higher coulombic efficiency was obtained with bad wine (45%) as the fuel. This work provides the scope of using these biofuel cells in wineries for performing the dual duty of bad wine degradation along with current generation. (C) 2011 Elsevier Ltd. All rights reserved.