Efficient degradation of polylactic acid plastics by a novel fungal strain Arthrinium phaeospermum and mechanistic insights.

Polylactic acid (PLA) plastic, as an eco-friendly alternative to traditional petroleum-based plastics, is increasingly being used worldwide. However, improper handling and management of PLA have led to accumulation in the environment, resulting in pollution. The development of efficient PLA-degrading strains is crucial for reducing pollution. In this study, a fungus (Arthrinium phaeospermum LF2024) is isolated from landfill areas and its degradation characterization of polylactic acid (PLA) plastic is evaluated. The fungal treatment resulted in 42.1 ± 3.7 % mass reduction of PLA in 40 days incubation. The average molecular weight of PLA decreased significantly by 78.0 % after fungal treatment with the increased polydispersity. Degradation characterization revealed the structure of the PLA has been significantly destroyed after treatment by scanning electron microscopy, X-ray diffraction analysis, fourier transform infrared spectroscopy and thermogravimetric analysis and differential scanning calorimeter analysis, leading to a significant increase in the hydrophilicity of the PLA after fungal treatment, while its tensile strength decreased by 85 %. Transcriptomic analysis identified the involvement of Cytochrome P450, alcohol oxidase, lipases and cutinases in the fungal depolymerization of PLA. These findings highlight the potential of microbial methods for efficient PLA degradation, offering a sustainable approach to mitigate environmental impact and promote eco-friendly waste management.