Techno-economic-environmental analysis of CO2 fermentation to acetic acid

Acetic acid, a key chemical in textiles, pharmaceuticals, and food industries, is largely produced via energy-intensive, fossil-based processes, driving greenhouse gas emissions. Gas fermentation using CO 2 and H 2 provides a sustainable alternative for bio-acetic acid production. The process, simulated on Aspen Plus®, targets the production of 37 kton.y −1 of glacial acetic acid (99.9 wt%). It includes an upstream phase to purify reactants, a fermentation stage, and a downstream step to concentrate the dilute culture broth into glacial acetic acid. H 2 is generated via alkaline water electrolysis, while CO₂ is captured using monoethanolamine absorption. The CO 2 originates from upgrading biogas into bio-methane, derived from anaerobic digestion of the organic fraction of municipal solid waste. Fermentation was modeled at 2 and 10 bar headspace pressures. Despite lower single-fermenter productivity, 2 bar operations reduced production costs and minimized formic acid formation, simplifying purification. The purification of acetic acid occurs with a hybrid process, which combines liquid-liquid extraction and azeotropic distillation using methyl tert-butyl ether as solvent, achieving 99.9 wt% purity. Economic analysis revealed an acetic acid production cost of 1.58 €.kg −1 for 37 kton.y −1 capacity, decreasing to 1.17 €.kg −1 at larger scales. With 2030 hydrogen cost projections, the acetic acid price could drop to 1.11 €.kg −1 , though remaining higher than the 2023 market price of 0.6 €.kg −1 . Environmental assessments proved that glacial bio-acetic acid production reached 47 % lower climate change impact, 73 % less fossil resource use, and 61 % reduced water consumption compared to traditional methods, confirming environmental benefits. • CO 2 and H 2 gas fermentation offers a sustainable route for bio-acetic acid production. • The process is simulated in Aspen Plus® to produce 99.9 % pure acetic acid. • Economic analysis shows an acetic acid production cost of 1.58 €.kg −1 for 37 kton.y −1 . • Environmental impact of the process is evaluated through the Life Cycle Assessment.