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Pivotal role of lactate-to-ethanol ratio in medium-chain fatty acids production without operational pH adjustment

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Název: Pivotal role of lactate-to-ethanol ratio in medium-chain fatty acids production without operational pH adjustment
Autoři: Samuel Gyebi Arhin, Alessandra Cesaro, Francesco Di Capua, Giovanni Esposito
Zdroj: Chemical Engineering Journal. 516:163675
Informace o vydavateli: Elsevier BV, 2025.
Rok vydání: 2025
Témata: Chain elongation, Co-electron donors, Food waste, Medium-chain fatty acids, pH control, Clostridium spp, Food waste, pH control, Medium-chain fatty acids, Clostridium spp, Co-electron donors, Chain elongation
Popis: Medium-chain fatty acids (MCFAs) production via chain elongation (CE) with endogenous ethanol or lactate as electron donors is a promising biotechnology for resource recovery from biowaste. However, a key bottleneck of the sole ethanol- or lactate-mediated CE is the requirement for exogenous buffering agents for pH control. In this study, we explored the possibility of system self-buffering by coupling ethanol and lactate as co-electron donors to capitalize on their respective net proton (H+) releasing and consuming behaviors during CE. Favorable pH conditions could be attained with a lactate-to-ethanol ratio of 1.5 (mM/mM). Combining lactate and ethanol as co-electron donors at a molar ratio of 1.5 facilitated MCFAs production (13.5 ± 1.7 g COD/L) and selectivity (43.4 ± 5.6 %, based on chemical oxygen demand) due to their complementary effects compared to when used in solitary. Ruminococcaceae bacterium CPB6 and Clostridium spp. were enriched in the co-electron donor-driven systems and could be associated with MCFAs production. The occurrence of genes encoding the fatty acid biosynthesis (FAB) pathway exceeded those assigned to the reverse β-oxidation pathway. The core FAB-related genes originated mainly from the putative MCFAs-producing species from class Clostridia. The results provide useful insights into high-value carboxylates production without operational pH adjustment and exogenous inorganic carbon supplementation.
Druh dokumentu: Article
Popis souboru: application/pdf
Jazyk: English
ISSN: 1385-8947
DOI: 10.1016/j.cej.2025.163675
Přístupová URL adresa: https://hdl.handle.net/11588/1005552
Rights: CC BY NC ND
Přístupové číslo: edsair.doi.dedup.....ffaf7792da097b1c550010afde4fa402
Databáze: OpenAIRE
Popis
Abstrakt:Medium-chain fatty acids (MCFAs) production via chain elongation (CE) with endogenous ethanol or lactate as electron donors is a promising biotechnology for resource recovery from biowaste. However, a key bottleneck of the sole ethanol- or lactate-mediated CE is the requirement for exogenous buffering agents for pH control. In this study, we explored the possibility of system self-buffering by coupling ethanol and lactate as co-electron donors to capitalize on their respective net proton (H+) releasing and consuming behaviors during CE. Favorable pH conditions could be attained with a lactate-to-ethanol ratio of 1.5 (mM/mM). Combining lactate and ethanol as co-electron donors at a molar ratio of 1.5 facilitated MCFAs production (13.5 ± 1.7 g COD/L) and selectivity (43.4 ± 5.6 %, based on chemical oxygen demand) due to their complementary effects compared to when used in solitary. Ruminococcaceae bacterium CPB6 and Clostridium spp. were enriched in the co-electron donor-driven systems and could be associated with MCFAs production. The occurrence of genes encoding the fatty acid biosynthesis (FAB) pathway exceeded those assigned to the reverse β-oxidation pathway. The core FAB-related genes originated mainly from the putative MCFAs-producing species from class Clostridia. The results provide useful insights into high-value carboxylates production without operational pH adjustment and exogenous inorganic carbon supplementation.
ISSN:13858947
DOI:10.1016/j.cej.2025.163675