Bacterial community structure and gene function prediction in response to long-term running of dual graphene modified bioelectrode bioelectrochemical systems.

•Bacterial community and gene function analysis were explored in LT D-GM-BE BES.•Maximum power density of LT D-GM-BE BES was 99.03 ± 3.64 mW/m2, 3.66 times of LT C-BE BES (2 year)•Proteobacteria/Firmicutes were dominant phylum in LT GM-BA, Armatimonadetes in LT GM-BC.•Dominant bacteria in LT GM-BA was Clostridium, GM-BC was Chthonomonas in genus.•Gene function for substrate, energy metabolism and environmental adaptation were enriched.