Influence of different exo-electrogens as biocatalyst on the bio-electrochemical behavior of H-type microbial fuel cell

Abstract

Being the source of electrons, microbes are the key players in MFCs; thus, it is imperative to investigate their effect on the bio-electrochemical processes therein so as to develop efficient systems with high power outputs. This study investigates the influence of four different anodic microbial cultures, Pseudomonas gessardii PG, Pseudomonas aeruginosa PA, Shewanella putrefaciens SP, and cowdung CD enriched inoculum, on the electrochemical performance of H-type MFC. Out of the four biocatalysts studied, most efficient electron transfer was observed in the case of PG, as indicated by the highest anodic peak current (0.717 mA) obtained by cyclic voltammograms and minimum internal resistance. Also, PG showed highest open circuit potential (OCP) and power density 504 mV and 1.05 W m⁻² respectively, followed by SP (280 mV, 0.56 W m⁻²), CD (227 mV, 0.192 W m⁻²) and PA (190 mV, 0.168 W m⁻²). High catabolic potential, active biofilm formation, and low corrosion rate were also identified as important reasons for better electrochemical performance observed in PG. Furthermore, SEM analysis of anodic biofilms revealed clusters of microbial cells attached to carbon cloth fibers (anode), while HR-TEM and epifluorescence images indicate the presence of elongated nanowires-like extensions in the cultures, which are supposedly involved in intercellular transport of electrons.