Unraveling interactive characteristics of microbial community associated with bioelectric energy production in sludge fermentation fluid-fed microbial fuel cells

[Display omitted] •Reveal large biodiversity related to high bioelectricity fed by WAS fermentation fluid.•Propose a novel scheme on synergistic interactions among key species for electrogenesis.•Uncover relatively medium community evenness reconstructed to better electrogenesis.•Highly abundant functional genes raised electrogenesis in WAS fermentation fluid-MFCs. This first-attempt study deciphered the interactive characteristics of anodophilic microbial community-associated bioelectricity production in waste activated sludge (WAS) fermentation fluid-fed microbial fuel cells (MFCs). A novel schematic elucidation for illustrating synergistic interactions in anodic microbial consortia towards electrogenesis was proposed. Moreover, the specific genera of Pseudomonas, Desulfovibrio, Phyllobacterium, Desulfuromonas, Chelatococcus and Aminivibrio were dominant in anodic biofilms, leading to an electrogenesis efficiency of 1.254 kWh/kg COD and peak power density of 0.182 W/m2 (at feeding level of 1.20 g COD/L). It was apparently higher than those MFCs fed with glucose/acetate. The fermentative species contributed positively in reorganizing microbial community structure in anodic biofilms, positively relating to electrogenesis via interactions with exoeletrogens in MFCs. Finally, a more electrogenesis was positively associated to larger anodic microbial diversity, relatively medium anodic community evenness, together with higher abundance of functional genes related to electrogenesis in functional species in MFCs fed with WAS fermentation fluid.