Chemolithoautotrophic reduction of CO2 to acetic acid in gas and gas-electro fermentation systems: Enrichment, microbial dynamics, and sustainability assessment

•Metagenomic revealed the abundance of CO2 consuming phyla in the biocatalyst.•Poised (-0.6 V) potential resulted electron recovery of 52 % in MES.•Sustainability assessment depicted the carbon neutral credit of the study.•Electrode morphology provided the adequate surface area for biofilm growth.•Semicontinuous CO2 sparging enhanced the gas liquid solubility.