The mycoremediation potential of phyllosphere fungi in urban ornamental plants in Sri Lanka with mathematical models for PAH degradation.

Currently, phylloremediation has emerged as a highly effective method for eliminating air pollutants, particularly polyaromatic hydrocarbons (PAHs). When PAHs accumulate on the phyllosphere, they significantly impact the fungal communities residing on leaf surfaces. This study aimed to investigate how pollution distribution patterns affect the diversity and PAH-degrading abilities of phyllosphere fungi, alongside identifying suitable mathematical models for PAH degradation. Leaf samples from two locations, Maradana and Sapugaskanda, were identified as having the highest PAH concentrations through principal component analysis. The fungal diversity in these highly contaminated regions was varied, with dominant species exhibiting greater PAH-degrading capabilities than those in less polluted areas. Thirty-five morphologically different epiphytic fungal strains were isolated on Potato Dextrose Agar (PDA) medium using the sample leaf wash. Two different fungal strains were selected as the best PAH degraders among those 35 different strains. These fungal strains were identified as <italic>Trichoderma harzianum</italic> P4M-16, and <italic>Fusarium solani</italic> P11M-46 based on ITS sequence data. Notably, these fungal species were more prevalent in highly polluted urban areas compared to less contaminated sites. High-Performance Liquid Chromatography (HPLC) analysis revealed that these two fungal species degrade PAHs more efficiently than others. Their kinetics assays demonstrated alignment with four degradation models when breaking down phenanthrene, naphthalene, pyrene, and anthracene. Scanning electron microscopy images showed that these fungi function as endophytes, extending their mycelium into the core leaf tissue layers beyond the epidermis. Gas Chromatography-Mass Spectrometry (GCMS) analysis indicated that <italic>F. solani</italic> P11M-46 produced non-toxic byproducts during the breakdown of phenanthrene and anthracene, confirming their eco-friendly nature. Overall, our findings suggest the promising potential of using phyllosphere fungi in bioremediation processes for environmental pollutants such as PAHs. [ABSTRACT FROM AUTHOR]