{
  "abstract": "Although Burkholderia cenocepacia exhibits biosurfactant-dependent phenotypes and possesses an rhl operon, the chemical identity of its surface-active product has long remained unresolved. The rhl operon of B. cenocepacia harbors an additional gene, rhlM, predicted to encode a methyltransferase, and recently linked to methylated rhamnolipid synthesis in a few Burkholderiaceae. Here, we hypothesized that this biosurfactant remained cryptic due to low expression under standard laboratory conditions. Using a chromosomal Prhl-luxCDABE fusion reporter, we screened diverse nutritional conditions and identified a defined medium containing galactose and urea that strongly induced rhl transcription. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses of B. cenocepacia K56-2 extracts identified the biosurfactants as methylated dirhamnolipid congeners, predominantly L-rhamnosyl-L-rhamnosyl-3-hydroxytetradecanoyl-3-hydroxytetradecanoate methyl ester (RR-C14-C14Me). Extending our analysis across the Burkholderia cepacia complex (Bcc) revealed that methylated rhamnolipid production is widespread and restricted to rhl-positive species. Comparative genomic and protein structural analyses further demonstrated high conservation of both the rhlM-containing operon architecture and the RhlM protein across the Bcc. Together, our findings identify the long-standing cryptic biosurfactant of B. cenocepacia as methylated rhamnolipids and establish rhamnolipid methylation as a conserved hallmark across the Bcc, shifting the paradigm of rhamnolipid structural diversity from an isolated exception to a widespread rule.",
  "abstract_shown": true,
  "affiliations": [
    "INRS-Armand-Frappier sante biotechnologie"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 4,
  "authors": [
    {
      "name": "M. Dagenais Roy"
    },
    {
      "name": "M.-C. Groleau"
    },
    {
      "name": "X. Perron"
    },
    {
      "affs": [
        0
      ],
      "name": "E. Deziel"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/0e07e318pwwfc.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.01.756062",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.10.01.756062v1.full",
  "id": "0e07e318pwwfc",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.10.01.756062v1",
  "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",
      "microbiology"
    ],
    [
      "openalex",
      "2310|Microbial bioremediation and biosurfactants"
    ]
  ],
  "openalex": "W7218618077",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.10.01.756062v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/0e07e318pwwfc.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:56Z",
      "native_id": "10.64898/2026.10.01.756062",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.10.01.756062v1"
    }
  ],
  "subjects": [
    {
      "field": "biology",
      "origin": "biorxiv:microbiology",
      "subfield": "microbiology"
    }
  ],
  "title": "From Exception to Rule: Widespread Production of Methylated Rhamnolipids in the Burkholderia cepacia Complex",
  "title_text": "From Exception to Rule: Widespread Production of Methylated Rhamnolipids in the Burkholderia cepacia Complex",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:56Z",
  "url": "https://research.draconitic.com/paper/0e07e318pwwfc",
  "venue": "bioRxiv",
  "versions": []
}