Performance of air-cathode microbial fuel cell (MFC) was evaluated using vanadium pentoxide microflowers (V2O5-MFs) catalyst on cathode and the results were compared with alpha-MnO2 nanotubes (alpha-MnO2-NTs). The oxygen reduction reaction (ORR) kinetics was determined using linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). MFC using V2O5MF produced 31% higher current density and 32% lower charge transfer resistance (R-ct) than alpha-MnO2-NT. An improved power density of 6.06 W m(-3) was observed in MFC using V2O5-MF catalyst, followed by the MFC using alpha-MnO2-NT (5.5 W m(-3)) and that without catalyst (0.81 W m(-3)). Furthermore, the coulombic efficiency of MFC using V2O5-MF (15.2%) was 17% and 52.6% higher than alpha-MnO2-NT and control, respectively. MFCs demonstrated significant fish market wastewater treatment with 80% removal of chemical oxygen demand (COD) and 60% protein removal efficiency. The overall performance of MFC using V2O5-MF catalyst was found to be superior, asserting it as a good catalyst, among low-cost metal based catalysts. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.