Fungal bioremediation of petroleum hydrocarbons in terrestrial environments: a systematic review and meta-analysis.

Petroleum hydrocarbon (PH) contamination in terrestrial environments is a serious global concern due to the toxicity and persistence of these compounds. Fungi are promising agents in bioremediation because of the ability to tolerate, degrade and metabolize complex and recalcitrant PHs. However, the use of other organisms, such as bacteria, remains more prevalent. Here, we evaluated the extent to which fungi have been investigated in PH bioremediation through a systematic review and meta-analysis following PRISMA guidelines. Among the 1,749 studies selected on bioremediation, only 348 included fungi, of which 97 met the inclusion criteria for quantitative analysis. Fungi were included in less studied (20% of articles) than bacteria and plants (63% and 31% respectively). However, our meta-analysis revealed that fungal treatments significantly reduced residual hydrocarbons by 50-60% in comparison with controls, with filamentous fungi (e.g., Trametes, Peniophora) showing the highest efficacy. Mycorrhizal fungi also demonstrated notable reduction (45-49%), while yeasts were less effective, particularly for polycyclic aromatic hydrocarbons (PAHs). We further identified that experimental variables, including treatment duration and the type of contaminated matrix, significantly influenced hydrocarbon reduction efficiency. Key limitations in the literature included a strong bias toward filamentous fungi and PAHs, as well as inconsistencies in experimental methodologies. Overall, our findings highlight the significant potential of fungi as bioremediation agents and emphasize the need to expand research on complex hydrocarbon mixtures (e.g., fuels) and underrepresented fungal groups, such as yeasts and mycorrhizal fungi, to better understand their role in reducing PH contamination in terrestrial ecosystems.