Leveraging Antarctic psychrotolerant fungi for PAH biodegradation, unveiling key factors influencing the process

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, detected even in remote regions such as the Antarctic, Arctic, and Tibetan Plateau. Thus, understanding their biodegradation processes at low temperatures is crucial. Therefore, the potential of fungal strains from the Antarctic to biodegrade PAHs was explored. Experiments were performed in a nutrient medium with 100 mg.L^-1 PAH, from 0 to 42 days at 120 rpm and 10-20 °C. Among the nine fungal strains assessed, eight demonstrated a statistically significant reduction in residual anthracene concentration (ranging from 58.1 to 92.9 mg.L^-1) compared to the killed-cell control (102.4 ± 4.7 mg.L^-1). Furthermore, the most efficient strain, Schizophyllum sp. LAMAI 2452, achieved a greater reduction in residual anthracene concentration compared to a consortium of six filamentous strains. Experimental design indicated that higher temperatures (20 °C) significantly enhanced the biodegradation efficiency of the best-performing strain and a consortium of three yeasts. In contrast, the consortium of six filamentous strains performed optimally at lower temperatures (10 °C), whereas pH levels did not significantly affect the biodegradation process. The assessed consortium biodegraded all the evaluated PAHs (anthrone, anthraquinone, acenaphthene, acenaphthylene, acenaphthenol, phenanthrene, and pyrene), and oxygenated and nitrogenated derivatives were identified as metabolites, contributing to a better understanding of the fate of these compounds. In summary, these biocatalysts effectively biodegraded different PAHs, providing insights into PAH degradation in extreme environments like Antarctica, while also opening avenues for discovering new biocatalysts for low-temperature processes.