Isolation of Exoelectrogenic Bacteria from Palm Oil Mill Effluent and Their Application in Microbial Fuel Cell

Abstract

The ability of exoelectrogenic bacteria to directly transfer electrons without any mediators to extracellular electron acceptors is vital in  microbial fuel cell technology. The current study evaluates the exoelectrogenic potential of bacteria isolated from Palm Oil Mill Effluent  (POME) in microbial fuel cell. The POME samples were obtained from Palm Oil mill factory in Iwo, Osun State, Nigeria. The isolates were  analysed on Chromogenic (differential) medium for colour change from black to whitish. The isolates were identified phenotypically and  molecularly. The potential of the isolates to generate efficient electricity were investigated in a doublechambered Microbial Fuel Cell  (MFC). Overall, ten isolates were obtained from POME sample, with only three isolates showing the exoelectrogenic potential by turning  the agar colour from black to whitish. The molecular analysis revealed three novel strains as Bacillus velezensis strain AAS001  (OQ690764), Bacillus amyloliquefaciens strain AAS002 (OQ690765) and Priestia aryabhattai strain AAS003 (OQ690766). Strain AAS003  showed the highest voltage potential of 1407mV compared to strain AAS001 with 229mV and strain AAS002 with 191mV. Similarly, the  power and current densities (345 mW/m² and 437 mA/m² respectively) recorded by strain AAS003 were far superior to that of strain  AAS001 (10 mW/m² and 64 mA/m² ) and strain AAS002 (15 mW/m² and 92 mA/m² ). This study suggests that strain AAS003 is an  excellent biocatalyst for bioelectricity generation.