Thermodynamic approach to foresee experimental CO2 reduction to organic compounds. (June 2022)

• Record Type: Journal Article
• Authors: Rovira-Alsina, Laura; Romans-Casas, Meritxell; Balaguer, M. Dolors; Puig, Sebastià
• Is Part Of: Bioresource technology. Volume 354(2022)
• Publication Date: 2022-06
• Subjects: Anaerobic fermentation -- Carboxylate platform -- Chain elongation -- CO2 valorization -- Open culture; Biomass -- Periodicals; Biomass energy -- Periodicals; Bioremediation -- Periodicals; Agricultural wastes -- Periodicals; Factory and trade waste -- Periodicals; Organic wastes -- Periodicals; Bioénergie -- Périodiques; Déchets agricoles -- Périodiques; Déchets industriels -- Périodiques; Déchets organiques -- Périodiques; Déchets (Combustible) -- Périodiques; 662.88
• DOI: 10.1016/j.biortech.2022.127181
• Languages: English
• ISSNs: 0960-8524

Abstract

Graphical abstract: Highlights: The potential procurement of elongated compounds from CO2 was studied and tested. The thermodynamic analysis revealed ethanol was the bottleneck for chain elongation. Experimental tests allowed fine-tuning of the operating conditions. The integration of thermodynamics and biology intensified caproic acid production. The highest caproic acid titter (>11 g L −1 ) was obtained from simple substrates. Abstract: Anaerobic gas fermentation is a promising approach to transform carbon dioxide (CO2 ) into chemical building blocks. However, the main operational conditions to enhance the process and its selectivity are still unknown. The main objective of this study was to trigger chain elongation from a joint perspective of thermodynamic and experimental assessment. Thermodynamics revealed that acetic acid formation was the most spontaneous reaction, followed by n-caproic and n-butyric acids, while the doorway for alcohols production was bounded by the selected conditions. Best parameters combinations were applied in three 0.12 L fermenters. Experimentally, n-caproic acid formation was boosted at pH 7, 37 °C, Acetate:Ethanol mass ratio of 1:3 and low H2 partial pressure. Though these conditions did not match with those required to produce their main substrates, the unification of both perspectives yielded the highest n-caproic acid concentration (>11 g L −1 ) so far from simple substrates, accounting for 77 % of the total products.