Abstract Soil contamination with petroleum asphaltenes represents a critical environmental hazard due to their recalcitrant nature and their potential long-term adverse effects on ecosystems, plants, animals, and human health. Bioremediation using microbial consortia capable of degrading heavy hydrocarbons offers a promising strategy for the efficient removal of asphaltenes from contaminated soils. This study aimed to develop a novel fungal consortium highly tolerant to asphaltenes for the bioremediation of contaminated soils and evaluate transcriptional responses during asphaltene degradation. The consortium, composed of Aspergillus oryzae , Penicillium citrinum , and Aspergillus sydowii , was evaluated in microcosm systems containing asphaltene-contaminated soil, and transcriptomic analyses were conducted to assess gene activity. Bioremediation assays revealed that the consortium not only removed but also mineralized asphaltenes, achieving a degradation of up to 55.6 wt% of 5000 mg of asphaltenes kg −1 in 30 days. Additionally, it exhibited remarkable tolerance to asphaltenes at concentrations exceeding 100,000 mg of asphaltenes l −1 . Transcriptomic profiling indicated that cytochrome P450 monooxygenases and extradiol dioxygenases were primarily involved during the initial stages of degradation, followed by upregulation of genes encoding laccases and DyP-type peroxidases, suggesting a coordinated metabolic response to the breakdown of complex aromatic compounds. The consortium demonstrated the ability to adapt and overexpress hydrocarbon-degrading genes in response to asphaltene exposure, underscoring its potential as an effective and viable bioremediation tool.
Barrera et al. (Wed,) studied this question.