Microbial Electrosynthesis and Anaerobic Fermentation: An Economic Evaluation for Acetic Acid Production from CO₂ and CO

Abstract

Microbial electrosynthesis (MES) and anaerobic fermentation (AF) are two biological processes capable of reducing CO, 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 £/kg, 1770 £/t) and AF (4.14 £/kg, 1598 £/t) because of variable and fixed costs and low production yields (100 t/y) compared to methanol carbonylation (0.26 £/kg, 261 £/t) and ethane direct oxidation (0.11 £/kg, 258 £/t). However, integrating AF with MES would reduce the release of CO, double production rates (200 t/y), and decrease investment costs by 9% (1366 £/t). This resulted into setting the production costs at 0.24 £/kg which is currently market competitive (0.48 £/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.

Bio-produced Acetic Acid: A Review

“…Glacial acetic acid is obtained at the top. The bottom product is passed through a solvent extraction system containing toluene or butyl acetate, and the oxidized organic impurities are removed with the solvent layer, while the MnO 4 − stays in the water layer to be reused [12].…”

Taking the technical microbiome into the next decade

“…A second option resides in the utilization of carbon dioxide from biogas or other point sources to produce carboxlyates through electrosynthesis (Nevin et al, 2010;Rabaey and Rozendal, 2010). The current lower production rates, compared to direct carboxylate production via fermentation, and subsequent high operational and capital cost, which are a factor of 5-10 higher than the actual value of, for example, acetate (Christodoulou and Velasquez-Orta, 2016), do not yet enable economic application of electrosynthesis as such. As a final option, biogas can serve as a carbon and energy source to produce microbial protein as animal feed or even human food (Matassa et al, 2015b;Pikaar et al, 2017).…”

Experimental evaluation of the influential factors of acetate production driven by a DC power system via CO2 reduction through microbial electrosynthesis

“…In comparison with pure strains Nevin et al 2010;Zhang et al 2013), mixed culture (Dong et al 2018;Marshall et al 2013;Modestra and Mohan 2017;Jourdin et al 2014;Patil et al 2015;Song et al 2017Song et al , 2018 is possibly more suitable for the commercialization of MES because it has better resistance to environmental disturbances, high biomass, and acetate production rate (Marshall et al 2013). The production and investment costs of producing acetate by MES (Christodoulou and Velasquez-Orta 2016) were relatively high (1.44 £ kg −1 , 1770 £ t −1 ). Therefore, it is necessary to increase the productivity of acetate further and reduce costs in order to advance toward industrialization.…”