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Electro-biocatalytic conversion of carbon dioxide to alcohols using gas diffusion electrode
- Srikanth, Sandipam, Singh, Dheer, Vanbroekhoven, K., Pant, Deepak, Kumar, Manoj, Puri, S.K., Ramakumar, S.S.V.
- Bioresource technology 2018 v.265 pp. 45-51
- acetic acids, biochemical pathways, butanol, butyric acid, carbon, carbon dioxide, electrodes, ethanol, mixed culture, pH, solubility, volatile fatty acids
- Impact of gas diffusion electrodes (GDEs) was evaluated in enhancing the CO2 bio-availability for its transformation to C4-organics, especially to alcohols using selective mixed culture. Observed current density was more stable (9–11 A/m2) than submerged experiments reported and significantly varied with pH and respective CO2 solubility. Uncontrolled operating pH (starting with 8.0) showed its impact on shifting/triggering alternate metabolic pathways to increase the carbon length (butyric acid) as well as producing more reduced end products, i.e. alcohols. During the experiments, CO2 was transformed initially to a mixture of volatile fatty acids dominated with formic and acetic acids, and upon their accumulation, ethanol and butanol production was triggered. Overall, 21 g/l of alcohols and 13 g/l of organic acids were accumulated in 90 days with a coulombic efficiency (CE) of 49%. Ethanol and butanol occupied respectively about 45% and 16% of total products, indicating larger potential of this technology.