Microbial analysis of anodic biofilm in a microbial fuel cell using slaughterhouse wastewater

Abstract

The ability of dual-chambered microbial fuel cell, fed with slaughterhouse wastewater with an anaerobic mixed-sludge as initial source of bacteria, to generate power is investigated. MFC voltage generation across a fixed 100Ω load indicates power generation capability, with power production correlated to changes in anolyte VFA content. A maximum MFC power density of 578mW/m2 is obtained for an MFC developed under 100Ω load, compared to a maximum power density of 277mW/m2 for an MFC developed under higher resistance (1MΩ) control conditions. Voltammetry of the biofilm developed under 100Ω load displays a current–voltage signal indicative of bioelectrocatalytic oxidation of feed at a potential of −0.35V vs. Ag/AgCl, compared to negligible signals for biofilms developed under control conditions. Denaturing gradient gel electrophoresis of PCR amplified 16S rRNA gene fragments reveals that the anodic bacterial communities in reactors operated under 100Ω load result in communities of lower diversity than for the control condition, with Geovibrio ferrireducens dominant in the anodic biofilm community. These results indicate that in MFC reactors, functionally stable electroactive bacteria are enriched under 100Ω load compared to high resistance control conditions, and were able to sustain higher power in MFCs.