CO2 valorization by a new microbiological process

Abstract

Carbon dioxide constitutes one of the largest carbon feedstocks for fuel production. This work demonstrates that an environmental bacterial consortium grown on methane is able to directly and selectively reduce CO2 into formate. The conversion was carried out at 30°C and atmospheric pressure, without any the addition of organic molecules (such as cofactor), photons or H2 to the reaction medium. When exposed to a CO2:air (1:1 v/v) mixture, the consortium was able to produce 280 ± 10 mg·g dry cell−1 of formate in 15 days. A control experiment performed solely with air coupled to NMR analysis suggested that at least 17% of the formate was produced from direct CO2 reduction. The formate produced could be used as a precursor for methanol production from methane by methanotrophic bacteria or it could be acidified to feed Direct Formic Acid Fuel Cells.