Microbial Electrosynthesis and Anaerobic Fermentation: An Economic Evaluation for Acetic Acid Production from CO2 and CO.
Microbial electrosynthesis (MES) and anaerobic fermentation (AF) are two biological processes capable of reducing CO2, CO, and water into acetic acid, an essential industrial reagent. In this study, we evaluated investment and production costs of acetic acid via MES and AF, and compared them to industrial chemical processes: methanol carbonylation and ethane direct oxidation. Production and investment costs were found high priced for MES (1.44 PS/kg, 1770 PS/t) and AF (4.14 PS/kg, 1598 PS/t) because of variable and fixed costs and low production yields (100 t/y) compared to methanol carbonylation (0.26 PS/kg, 261 PS/t) and ethane direct oxidation (0.11 PS/kg, 258 PS/t) However, integrating AF with MES would reduce the release of CO2, double production rates (200 t/y) and decrease investment costs by 9% (1366 PS/t) This resulted into setting the production costs at 0.24 PS/kg which is currently market competitive (0.48 PS/kg) This economically feasible bioprocess produced molar flow rates of 4550 mol per day from MES and AF independently. Our findings offer a bright opportunity toward the use and scale up of MES and AF for an economically viable acetic acid production process.
Environmental science technology