Diversity of Fungi Isolated from Iraqi Petroleum-Contaminated Soils (Baiji Refinery and Middle Oil Company)

Fungi are important decomposers of complex organic pollutants and have an enormous potential for use in bioremediation of petroleum-laden environments. In the current study, we investigated the diversity, distribution, and oil-degrading potential of fungi isolated from petroleum-contaminated soils in Iraq, specifically Baiji Refinery and Middle Oil Company. Fifteen soil samples were collected from each location as outlined between the months of September and November 2024. Fungal isolates were purified and identified based on morphological and microscopic examinations of the fungi using standard taxonomic keys. A total of 232 isolates were obtained, largely belonging to Ascomycota, with the predominant species being Aspergillus flavus, followed by Cladosporium sp., Penicillium griseofulvum, and Candida spp. quantitatively analyzed patterns revealed a significantly different frequency and occurrence of fungal isolates among each of the locations, which suggest that these species adapted to their hydrocarbon-rich environments. The presence of these oil-tolerant species suggests their potential enzymatic capabilities for the degradation of petroleum hydrocarbons and the ecological role they play in contaminated ecosystems. This is the first systematic study with culturable oil-degrading fungi from Iraqi petroleum-contaminated soils for basic research and applied bioremediation efforts using native fungal strains