Microplastic pollution and eco-friendly approaches to microplastic degradation: the role of fungal enzymes in a sustainable future

Microplastics, which are plastic residues smaller than 5 mm, are very hard to extract from lakes and rivers, sediments, and the air using current methods because of their tiny size. Some suitable sampling procedures for MPs and methods for identifying them in environmental samples will be highlighted in the review. MPs are ubiquitous in the majority of daily activities. Fungi have emerged as some of the most efficient microbial degraders of polymers, owing to their ability to produce potent enzymes and survive on substrates that are typically resistant to degradation. The potential for engineering applications of fungal enzymes in plastic decomposition is significant and environmentally sustainable. This review evaluates the current understanding of the roles fungi and their enzymes play in degrading synthetic polymers, with a focus on their metabolic pathways and mechanisms of action. Consequently, this assessment emphasises the degradation mechanisms of hydrolases/oxidoreductases for the decomposition of produced polymers, in light of the most modern stages in this field of research. The degradation of plastics is significantly influenced by enzymes such as laccase, peroxidase, lipase, and cutinases. Laccase facilitates polymer chain cleavage by generating reactive oxygen species using oxygen; esterases hydrolyse polymers into smaller fragments; peroxidases produce radicals that enhance polymer breakdown; and lipases contribute to substrate degradation. The degradation of plastic substrates is also facilitated by lipases. The review also discusses the potential for fungal enzymes in future biotechnological applications in plastic degradation, as well as the challenges that need to be addressed for efficient biological remediation approaches.