Multi-omics insights into the enzymatic degradation of polyurethane by marine fungi

The proliferation of plastic waste presents a critical global environmental challenge. Marine-derived fungi are increasingly recognized as promising biological agents for synthetic polymer breakdown; however, the underlying molecular mechanisms remain elusive. In this study, we applied a comprehensive multi-omics strategy to investigate how selected marine fungi degrade a polyurethane (PU) substrate. High-resolution LC-MS/MS analysis revealed a diverse suite of low-molecular-weight products enriched in strains that degraded the polymer up to 100% in 28 days, consistent with ester-bond hydrolysis and oxidative modification of the polymer backbone. In-depth metabolomics supported the presence of chain-length variants and predicted ester cleavage sites. NMR analysis of the PU mixture provided complementary evidence for the proposed monomer composition. Genomic screening and transcriptome profiling of the two active strains uncovered more than 90 candidate cutinases/esterases and other enzyme families with differential expression under PU vs glucose conditions. Our integrative multiomics dataset strongly suggests marine fungi harbor a broad, largely uncatalogued enzyme repertoire that allows them to target ester-bonds in PU. These findings advance the molecular understanding of fungal polyurethane degradation and highlight marine fungi as a promising source of enzymatic tools for plastic-waste bioremediation. • Marine fungi were found to rapidly degrade polyurethane (Impranil) in a plate-based assay. • LC-MS/MS and molecular networking analysis identified an abundance of small products consistent with ester hydrolysis. • Genomes and RNA-seq nominate putative cutinases/esterases as candidate enzymes. • Multi-omics evidence points to ester-bond targeting by fungi, with biochemical validation pending.