The bionic leaf: A platform for scalable and efficient solar-to-fuels transformations using biotic and abiotic catalysts

Solar energy demonstrates significant potential to meet our need for renewable energy; however storing captured energy in a scalable and efficient manner will be necessary for wide implementation. Here, we report an integrated, scalable bioelectrochemical system where the bacterium Ralstonia eutropha efficiently processes CO2, along with H2 and O2 derived from water splitting, into biomass and fusel alcohols. Electrolysis was performed using scalable “artificial leaf” electrodes made of earth-abundant metals that enable low-overpotential water splitting. This bioelectrochemical system achieves biomass yields from solar energy of up to 3.2% of the thermodynamic maximum, exceeding that of most terrestrial plants. Further, incorporation of engineered R. eutropha strains enabled the production of the fusel alcohol isopropanol at up to 216mg/L, the highest fuel yield in a bioelectrochemical system reported by >300%. This work demonstrates that biotic and abiotic technologies can interface to surmount difficult obstacles in attaining renewable energy.