Electricity generation using microbial fuel cells

Conversion of biomass into electricity is possible using microbial fuel cells (MFCs). The present paper deals with the studies of a two-chambered salt bridge MFC using Enterobacter cloacae IIT-BT 08 in MYG medium. The effect of different electron mediators, concentration of the mediator, ionic strength (salt concentration) of the medium and the surface area of the salt-bridge in contact with the anode and cathode chambers on the power generation in MFCs are reported. In the case of methyl viologen (MV) (0.1 mM) as the electron mediator, the voltage generation was 0.4 V but no current was detected. Different concentrations of methylene blue (MB) were also studied as the mediator. A maximum voltage of 0.37 V was seen at 0.05 mM NIB, whereas a maximum current and power of 56.7 mu A and 19.2 mu W, respectively, were observed in the case of 0.03 mM MB with a voltage of 0.34 V. The corresponding power density and current density of 9.3 mW/m(2) and 27.6 mA/m(2), respectively, were obtained. When the surface area of the salt bridge in contact with the anode and cathode chambers was increased, a proportionate improvement in the power output from 19.2 to 708 mu W was detected. The maximum power density and current density of 236 mW/m(2) and 666.7 mA/m(2), respectively, which are found to be very promising for a salt bridge MFC were observed. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.