The electrospun carbon nanofibers obtained from polyacrylonitrile (PAN) and PAN blends with either activated carbon (PAN-AC) or graphite (PAN-GR) were tested as anodes using Shewanella oneidensis MR-1. Extensive physico-chemical and electrochemical characterization confirmed their formation, their fibrous and porous nature, and their suitability as electrodes. N-2 adsorption measurements revealed high specific surface area (229.8, 415.8 and 485.2 m(2) g(-1)) and porosity (0.142, 0.202 and 0.239 cm(3)g(-1)) for PAN, PAN-AC and PAN-GR, respectively. The chronoamperometric measurements showed a considerable decrease in start-up time and more than a 10-fold increase in the generation of current with these electrodes (115, 139 and 155 mu A cm(-2) for PAN, PAN-AC and PAN-GR, respectively) compared to the graphite electrode (11.51 mu A cm(-2)). These results indicate that the bioelectrocatalysis benefits from the blending of PAN with activated or graphitized carbonaceous materials, presumably due to the increased specific surface area, total pore volume and modification of the carbon microstructure. (C) 2013 Elsevier Ltd. All rights reserved.