Acetogenesis to ethanologenesis: facilitating NADH oxidation via reductive acetate uptake
(Homo)acetogens, including Clostridium spp., represent an enigma in metabolic flexibility and diversity. Eubacterium callanderi KIST612 is an acetogen that produces n-butyrate with carbon monoxide (CO) as the carbon and energy source; however, the production route is unknown. Here, we report that its distinctive butyrate formation links to reductive acetate uptake, suggesting that acetate (the end-product) is reuptake, leading to a physiological advantage through NADH oxidation. Thus, we introduced an ethanol production pathway from acetyl-CoA as a competitive pathway for butyrate production. Consequently, the metabolic pathway in our mutants switched from acetogenesis to 'ethanologenesis', eliminating butyrate production and the uptake of previously produced acetate. The metabolic shifts occurred toward greater NADH oxidation, facilitating CO oxidation and productivity, which is a survival mechanism at the thermodynamic edge. This metabolic shift to a single product holds potential to revolutionize product separation strategies in synthetic gas (syngas)-based biorefineries.
Authors
- Byeongchan Kang
- Byeonghyeok Park (ORCID: https://orcid.org/0000-0002-8187-7650)
- Kyung‐Hoon Shin (ORCID: https://orcid.org/0000-0002-3169-4274)
- Junhyeok Seo (ORCID: https://orcid.org/0000-0002-9436-6964)
- In Seop Chang (ORCID: https://orcid.org/0000-0001-5064-7951)
- Jiyeong Jeong
- Volker Müller (ORCID: https://orcid.org/0000-0001-7955-5508)
- Seung-Hyeon Jung
- Mungyu Lee (ORCID: https://orcid.org/0009-0003-8290-3536)
- In‐Geol Choi (ORCID: https://orcid.org/0000-0001-7403-6274)
- W.N. Paul Lee
- Ji-Yeon Kim (ORCID: https://orcid.org/0000-0002-1425-1754)
- So‐Young Oh (ORCID: https://orcid.org/0000-0003-3183-6508)
- Sehoon Park (ORCID: https://orcid.org/0000-0001-5951-2420)
- Muhammad Yasin (ORCID: https://orcid.org/0000-0002-0322-7919)
- Zee‐Yong Park (ORCID: https://orcid.org/0000-0002-8184-5982)
- Dong‐Hun Lee
Institutions
- Goethe University Frankfurt (DE)
- COMSATS University Islamabad (PK)
- Korea University (KR)
- Gwangju Institute of Science and Technology (KR)
- Hanyang University (KR)
Publication Details
- Journal
- Trends in biotechnology
- Published
- 2025-01-09
- DOI
- https://doi.org/10.1016/j.tibtech.2024.11.008
- Citations
- 8
- Primary Topic
- Microbial Metabolic Engineering and Bioproduction
- Type
- article
- Field-Weighted Citation Impact
- 6.45
Funders
- Ministry of Trade, Industry and Energy
- National Research Foundation of Korea
- Korea Institute of Energy Technology Evaluation and Planning