Different Electron Donors Drive the Variation in the Performance of Medium-Chain Fatty Acid Production from Waste-Activated Sludge

Wang, Y; Wei, W; Dai, X; Wu, L; Chen, X; Ni, BJ

Different Electron Donors Drive the Variation in the Performance of Medium-Chain Fatty Acid Production from Waste-Activated Sludge

Wang, Y Wei, W

Dai, X Wu, L

Chen, X Ni, BJ

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Publisher:: AMER CHEMICAL SOC
Publication Type:: Journal Article
Citation:: ACS ES and T Engineering, 2023
Issue Date:: 2023-01-01

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Field	Value	Language
dc.contributor.author	Wang, Y
dc.contributor.author	Wei, W https://orcid.org/0000-0001-5613-337X
dc.contributor.author	Dai, X
dc.contributor.author	Wu, L https://orcid.org/0000-0001-8581-2937
dc.contributor.author	Chen, X
dc.contributor.author	Ni, BJ
dc.date.accessioned	2024-03-12T02:38:26Z
dc.date.available	2024-03-12T02:38:26Z
dc.date.issued	2023-01-01
dc.identifier.citation	ACS ES and T Engineering, 2023
dc.identifier.issn	2690-0645
dc.identifier.issn	2690-0645
dc.identifier.uri	http://hdl.handle.net/10453/176542
dc.description.abstract	Producing high-value medium-chain fatty acids (MCFAs) via anaerobic fermentation is an emerging green biotechnology to recover bioenergy from waste-activated sludge (WAS). Electron donor (ED) is a key driver affecting the MCFA production profiles. This study investigated and compared the potential of using ethanol, lactate, and a combination of both as ED supplies (Co-EDs) for enhancing MCFA production during anaerobic WAS fermentation. Adopting ethanol as the sole ED was the optimal strategy to attain the highest MCFA production (3352.7 ± 564.7 mg of COD/L) and selectivity (20.7%) from WAS. Although lactate dosage promoted WAS degradation, more organics were converted to short-chain fatty acids (SCFAs) rather than MCFAs, resulting in the lowest MCFA production (1034.8 ± 303.6 mg of COD/L) afterward. Lactate- and Co-EDs-added systems enriched hydrolytic bacteria and SCFA producers to a higher level than the reactor with an ethanol supplement. Nevertheless, the richest abundance of Clostridium_kluyveri, a key MCFA producer, was attained in the ethanol-added system. Further metatranscriptomic analysis mapped all expressed metabolic pathways involved in MCFA production and revealed that no synergistic effect was observed in the Co-ED system. The insufficient electron acceptor (EA) synthesis at the initial stage induced the inefficiency in ED usage for CE, rendering a huge waste of ED (i.e., lactate) via the competitive acrylate pathway. In comparison, the gene abundance related to the CE cycle was the highest in the ethanol system. This study provided useful information and insights for enhancing the MCFA yield by optimizing ED composition from various substrates.
dc.language	English
dc.publisher	AMER CHEMICAL SOC
dc.relation	http://purl.org/au-research/grants/arc/DP220101139
dc.relation	http://purl.org/au-research/grants/arc/DE220100530
dc.relation.ispartof	ACS ES and T Engineering
dc.relation.isbasedon	10.1021/acsestengg.3c00423
dc.rights	info:eu-repo/semantics/closedAccess
dc.title	Different Electron Donors Drive the Variation in the Performance of Medium-Chain Fatty Acid Production from Waste-Activated Sludge
dc.type	Journal Article
pubs.organisational-group	University of Technology Sydney
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	University of Technology Sydney/Faculty of Engineering and Information Technology/School of Civil and Environmental Engineering
utslib.copyright.status	closed_access	*
dc.date.updated	2024-03-12T02:38:24Z
pubs.publication-status	Published

Abstract:

Producing high-value medium-chain fatty acids (MCFAs) via anaerobic fermentation is an emerging green biotechnology to recover bioenergy from waste-activated sludge (WAS). Electron donor (ED) is a key driver affecting the MCFA production profiles. This study investigated and compared the potential of using ethanol, lactate, and a combination of both as ED supplies (Co-EDs) for enhancing MCFA production during anaerobic WAS fermentation. Adopting ethanol as the sole ED was the optimal strategy to attain the highest MCFA production (3352.7 ± 564.7 mg of COD/L) and selectivity (20.7%) from WAS. Although lactate dosage promoted WAS degradation, more organics were converted to short-chain fatty acids (SCFAs) rather than MCFAs, resulting in the lowest MCFA production (1034.8 ± 303.6 mg of COD/L) afterward. Lactate- and Co-EDs-added systems enriched hydrolytic bacteria and SCFA producers to a higher level than the reactor with an ethanol supplement. Nevertheless, the richest abundance of Clostridium_kluyveri, a key MCFA producer, was attained in the ethanol-added system. Further metatranscriptomic analysis mapped all expressed metabolic pathways involved in MCFA production and revealed that no synergistic effect was observed in the Co-ED system. The insufficient electron acceptor (EA) synthesis at the initial stage induced the inefficiency in ED usage for CE, rendering a huge waste of ED (i.e., lactate) via the competitive acrylate pathway. In comparison, the gene abundance related to the CE cycle was the highest in the ethanol system. This study provided useful information and insights for enhancing the MCFA yield by optimizing ED composition from various substrates.

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http://hdl.handle.net/10453/176542