Degradation of Bunker C Fuel Oil by White-Rot Fungi in Sawdust Cultures Suggests Potential Applications in Bioremediation

PLoS One. 2015 Jun 25;10(6):e0130381. doi: 10.1371/journal.pone.0130381. eCollection 2015.

Abstract

Fungal lignocellulolytic enzymes are promising agents for oxidizing pollutants. This study investigated degradation of Number 6 "Bunker C" fuel oil compounds by the white-rot fungi Irpex lacteus, Trichaptum biforme, Phlebia radiata, Trametes versicolor, and Pleurotus ostreatus (Basidiomycota, Agaricomycetes). Averaging across all studied species, 98.1%, 48.6%, and 76.4% of the initial Bunker C C10 alkane, C14 alkane, and phenanthrene, respectively were degraded after 180 days of fungal growth on pine media. This study also investigated whether Bunker C oil induces changes in gene expression in the white-rot fungus Punctularia strigosozonata, for which a complete reference genome is available. After 20 days of growth, a monokaryon P. strigosozonata strain degraded 99% of the initial C10 alkane in both pine and aspen media but did not affect the amounts of the C14 alkane or phenanthrene. Differential gene expression analysis identified 119 genes with ≥ log2(2-fold) greater expression in one or more treatment comparisons. Six genes were significantly upregulated in media containing oil; these genes included three enzymes with potential roles in xenobiotic biotransformation. Carbohydrate metabolism genes showing differential expression significantly accumulated transcripts on aspen vs. pine substrates, perhaps reflecting white-rot adaptations to growth on hardwood substrates. The mechanisms by which P. strigosozonata may degrade complex oil compounds remain obscure, but degradation results of the 180-day cultures suggest that diverse white-rot fungi have promise for bioremediation of petroleum fuels.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Basidiomycota / chemistry
  • Basidiomycota / genetics
  • Basidiomycota / metabolism*
  • Biodegradation, Environmental*
  • Carbohydrate Metabolism / genetics
  • Environmental Pollutants / chemistry
  • Fuel Oils / toxicity*
  • Fungi / chemistry*
  • Fungi / metabolism
  • Gene Expression Regulation, Fungal / drug effects
  • Humans
  • Oxidants

Substances

  • Environmental Pollutants
  • Fuel Oils
  • Oxidants