Regulated surface potential impacts bioelectrogenic activity, interfacial electron transfer and microbial dynamics in microbial fuel cell

Abstract

Influence of surface anode potential on the performance of microbial fuel cell (MFC) was evaluated by opting positive and negative poised anode potentials (+100/-100 mV) on two MFCs, and studied at two phases (during potential (DP) and post potential (PP)) along with a third MFC operated as control (no applied anode potential). Variation in physico-chemical factors as well as biocatalytic metabolic behavior was analyzed in terms of electron transfer, power density, electro-kinetics and microbial community. Post potential operation at −100 mV depicted rapid electron transfer, higher redox catalytic currents (−0.44/0.42 mA) and voltage (653 ± 28 mV) in comparison to other experimental conditions. Disparity in electron carriers is noticed at both the phases with +100 mV (dominantly direct electron transfer)/-100 mV (cytochrome components) potential as well as control (non-specific and multiple carriers) which signify alteration in electron transfer mechanism aligned with change in surface potential. Microbial community analysis depicted the enrichment of exo-electrogenic bacteria belonging to phylum Proteobacteria (Gram negative bacteria) dominant at −100 mV, while Firmicutes (Gram positive bacteria) at +100 mV and a mixed bacterial population at control. Electrochemical investigations correlated with biological efficiency of MFC, which discerns a way to comprehend the underlying electron transfer process triggered in response to change in anode potential.