Three different approaches were employed to improve single chambered microbial fuel cell (sMFC) performance using Shewanella putrefaciens as biocatalyst. Taguchi design was used to identify the key process parameter (anolyte concentration, CaCl2 and initial anolyte pH) for maximization of volumetric power. Supplementation of CaCl2 was found most significant and maximum power density of 4.92 W/m(3) was achieved. In subsequent approaches, effect on power output by riboflavin supplementation to anolyte and anode surface modification using nano-hematite (Fe2O3) was observed. Volumetric power density was increased by 44% with addition of 100 nM riboflavin to anolyte while with 0.8 mg/cm(2) nano-Fe2O3 impregnated anode power density and columbic efficiency increased by 40% and 33% respectively. Cyclic voltammetry revealed improvement in electrochemical activity of Shewanella with nano-Fe2O3 loading and electrochemical impedance depicted inverse relationship between charge transfer resistance and nano-Fe2O3 loading. This study suggests anodic improvement strategies for maximization of power output. (C) 2014 Elsevier Ltd. All rights reserved.