Bioelectrogeneic performance of air-cathode microbial fuel cells with diesel contaminants

Abstract

Bioremediation of diesel contaminants and then harnessing the bioenergy could be another cost‐effective and eco‐friendly solution to hydrocarbons soil contaminants. Four series of parallel circuit air–cathode MFCs (100 mL working volume) were operated under different diesel concentrations using acclimated bacterial consortium from diesel contaminated soil. Maximum current (Imax = 43.11 mA) under applied potential was recorded using fuel cell (DMFC-31DMFC-3 = 50mlL−1 diesel concentration in microbial fuel cells.1) fed with 50 mlL−1 diesel (substrate), whereas it was 10 mA in DMFC-122DMFC-1 = 0mlL−1 diesel concentration in microbial fuel cells. (0 mlL−1), Imax of 9.6 mA in DMFC-23DMFC-2 = 10mlL−1 diesel concentration in microbial fuel cells.3(10 mlL−1) while in DMFC-444DMFC-4 = 100mlL−1 diesel concentration in microbial fuel cells. (100 mlL−1) Imax of 18.47 mA was recorded. Cyclic voltammogram and CLSM clearly indicated the effect of different diesel concentrations on the electrogenic performance of anode respiring bacteria (ARB). Six less explored, culturable species of ARB enriched bacteria on anodic biofilms in DMFC-3 were procured and characterized on molecular basis (16S rRNA gene) as Paenibacillus sp. (MN173851), Bacillus toyonensis (MN173853), Ochrobactrum sp. (MN173857), Bacillus sp. (MN173854), Bacillus methylotrophicus (MN173856), and Bacillus licheniformis (MN173855). Bioelectrochemical activity of Bacillus toyonensis (MN173853) was typically monitored for the first time in MFC reactors. Among the tested organisms, Bacillus sp., was found to have greatest biodegradation capability with rate of 88% followed by Paenibacillus sp. 85%, Ochrobactrum sp. 79% by fast decolourization of redox indicator. The present study verified the presence and suitability of ARB under the influence of diesel in MFCs.