Continuous bioelectricity generation was studied in a novel up-flow bio-cathode microbial fuel cell (MFC). The performance of MFC-1, employing commercially available proton exchange membrane (PEM), was evaluated under different organic loading rates (OLRs). Maximum volumetric power density of 10.04 W m(-3) was obtained in MFC-1 at the OLR of 0.923 kg COD m(-3) d(-1). Overall chemical oxygen demand (COD) removal efficiency more than 90% was achieved under all the OLRs. The performance of MFC-1 was compared with MFC-2, in which the inner anode chamber was made up of earthen cylinder, without employing polymer membrane. MFC-2 generated maximum volumetric power density of 14.59 W m(-3) at OLR of 0.923 kg COD m(-3) d(-1), which was 46% higher than that produced in MFC-1. The internal resistance of MFC-1 (96 Omega) was higher than MFC-2 (69 Omega). The earthen cylinder MFC demonstrated better COD removal and power generation than the MFC employing PEM. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.