Coupled iron-microbial catalysis for CO 2 hydrogenation with multispecies microbial communities

•Multispecies microbial consortia catalyse CO2 hydrogenation.•Iron ions at a few mM concentration considerably enhanced the microbial catalysis.•Both the final concentration of the products and the production rates were increased.•High production rate was sustained for weeks without product extraction or pH control.•Iron enhanced the selection of the two microbial genera Clostridium and Megasphaera.