Elucidation of the biodegradation pathways of polyurethane and polyethylene terephthalate by a Fusarium strain...

Fungi are emerging as a promising solution for bioremediation. Several fungi have been identified to degrade polyester, but the specific molecular mechanisms involved remain poorly understood. In this study, we screened for polyester-degrading fungus, characterised its ability to depolymerise both polyurethane (PU) and polyethylene terephthalate (PET), and employed a multi-omics approach to identify key proteins involved in PU and PET hydrolysis. Incubation of F. vanettenii together with PU and PET films resulted in 19.70% and 6.63% mass loss, respectively. The strain colonised plastic surfaces and significantly reduced peaks for carbonyl, esters, and amides groups, and further induced stretching of methylene bonds in both plastics. LC-MS detection of the products generated identified propylene glycol, hexanoic and adipic acids from PU, while catechol and terephthalic acid were recorded from PET. Transcriptomic and proteomic analyses revealed distinct upregulation of lipases FvLIP1 and FvLIP2, signalling their role in polyester hydrolysis. RT-qPCR confirmed the upregulation of key enzymes, with FvLIP1 and FvCUT1 enriched under PU, and FvLIP2, FvCUT2, FvLAC1, and FvMCO more responsive to PET. Extracellular lipases FvLIP1 and FvLIP2 were selected for protein docking. Docking analysis revealed hydrophobic π-sigma and alkyl interactions and hydrogen bonding between amino acid residues in FvLIP1 and FvLIP2 with PU and PET. This study provides the first integrated omics-based framework for F. vanettenii, highlighting the enzymatic strategy employed by a single fungus to degrade multiple plastics.