Microcosm-dependent degradation of nonwoven fabric in surgical masks by endophytic fungi Aspergillus bridgerii.

The widespread use of polypropylene-based surgical masks during the COVID-19 pandemic has exacerbated environmental plastic pollution, necessitating sustainable degradation strategies. This study investigates the biodegradation potential of the endophytic fungus Aspergillus bridgerii on nonwoven polypropylene mask layers under both nutrient-rich (MSM broth) and soil microcosm conditions. A multidisciplinary approach combining weight loss measurements, FTIR-ATR spectral analysis, scanning electron microscopy (SEM), and gas chromatography-mass spectrometry (GC-MS) was employed to characterize physical, chemical, and biochemical changes in the polymer matrix. Results show that A. bridgerii induced significant degradation in both environments, with the highest weight loss % observed in MSM microcosms (20.38 ± 0.29 %), indicating active fragmentation and partial mineralization. In soil microcosms, fungal inoculation led to the most advanced oxidation (SAUB CI up to ∼4.6), extensive surface fragmentation, and the release of unique volatile organic compounds (VOCs), including DEHP (∼15 % GC-MS area) and long-chain ketones. Surprisingly, this was accompanied by the lowest residual mask mass (9.48 ± 0.19 %), suggesting enhanced mineralization in the nutrient-limited soil. SEM analysis further confirmed pronounced fiber degradation and biofilm formation. These findings underscore the role of fungal metabolism and environmental context in modulating polypropylene decay, supporting a multiple mechanistic process such as oxidative fragmentation followed by microbial assimilation. The integration of FTIR, SEM, and GC-MS provided robust evidence of mask polymer degradation and highlights the potential of Aspergillus bridgerii as a bioremediation agent for PPE waste.