{
  "abstract": "Acetogens are promising microbial catalysts for the sustainable production of fuels and chemicals, metabolizing a range of renewable single-carbon (C1) compounds with high energetic efficiency. The major challenge is their energy-limited anaerobic lifestyle, which results in slow growth and a limited product spectrum on individual C1 substrates. We previously showed in the acetogen Eubacterium limosum that co-metabolism of glucose-methanol or CO-methanol mixtures results in substantial improvements in growth and acetate productivity. To investigate the underlying mechanism(s), here we conducted 13C metabolic flux analysis (13C-MFA) of E. limosum grown on a glucose-methanol mixture, as well as in single-substrate controls. The results suggest that the main benefit of glucose cofeeding is not provision of additional ATP, but rather a reduction of flux through the ferredoxin-dependent and kinetically challenging reactions of the Wood-Ljungdahl pathway. Subsequent RNAseq analysis showed no significant differences in the expression level of genes involved in methanol metabolism between cofeeding and methanol-only controls, suggesting this reduction of flux is controlled post-transcriptionally. Most surprisingly, we found that under all growth conditions, flux through pyruvate:ferredoxin oxidoreductase (PFOR) was in the oxidative direction, with cysteine (added as a reducing agent) providing all required gluconeogenic carbon flux under CO2-fixing conditions. This work provides critical insights into the metabolic network of an emerging model acetogen that will facilitate future metabolic engineering efforts to channel flux to value-added products, and highlights the under-appreciated role of cysteine as a carbon source in acetogenic fermentations.",
  "abstract_shown": true,
  "affiliations": [
    "Northeastern University"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "name": "K. O. Hoyt"
    },
    {
      "name": "W. Gasparrini"
    },
    {
      "name": "J. A. Hayes"
    },
    {
      "affs": [
        0
      ],
      "name": "B. M. Woolston"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f9wp9taccpcz3.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.12.758492",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758492v1.full",
  "id": "f9wp9taccpcz3",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758492v1",
  "language": null,
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "systems biology"
    ],
    [
      "openalex",
      "1312|Microbial Metabolic Engineering and Bioproduction"
    ]
  ],
  "openalex": "W7221768154",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758492v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-12",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/f9wp9taccpcz3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:42Z",
      "native_id": "10.64898/2026.10.12.758492",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.10.12.758492v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "biorxiv:systems biology",
      "subfield": "systems-synthetic"
    }
  ],
  "title": "13C-Metabolic Flux Analysis of Substrate Co-Metabolism in the Methylotrophic Acetogen Eubacterium limosum.",
  "title_text": "13C-Metabolic Flux Analysis of Substrate Co-Metabolism in the Methylotrophic Acetogen Eubacterium limosum.",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:42Z",
  "url": "https://research.draconitic.com/paper/f9wp9taccpcz3",
  "venue": "bioRxiv",
  "versions": []
}