From the paper: > Chemical and energy inputs and product yield were determined using pilot-scale data coupled with design data from industrial-scale ethanol pr

From the paper: > Chemical and energy inputs and product yield were determined using pilot-scale data coupled with design data from industrial-scale ethanol production, which uses steel mill off-gas feedstock with utilities (for example, electricity and steam) > The GHG emissions of acetone and IPA produced by the gas fermentation process (Fig. 6c) are −1.78 kgCO2e/kg acetone and −1.17 kgCO2e/kg IPA, respectively. The negative value is due to avoided off-gas emissions combined with low process emissions (Fig. 6c), effectively locking carbon into the product. > After transformation into C. autoethanogenum strain, the resulting acetone combinatorial strains were subjected to Schott bottle growth on 1.5-bar synthetic gas blend (50% CO, 10% H2, 30% CO2 and 10% N2; Airgas) I wonder what sort of energy is required to generate that sort of gas mixture from atmospheric CO2 concentrations (0.0412% these days), and whether the CO and H2 are essential. It looks like that (and the 1.5-bar pressurization) are the only substantial energy inputs to the process. Or, alternately, I wonder how many tons of such a mixture are industrially produced currently.