Isolation, Identification, and Characterization of Novel Environmental Bacteria with Polyurethane-Degrading Activity

Polyurethane (PU) is a widely used plastic material whose persistence in the environment entails a serious ecological challenge. This study aimed to isolate and characterize environmental bacteria capable of degrading PU, using Impranil DLN as a model substrate, and to investigate their enzymatic mechanisms and phylogenetic relationships. A total of 31 bacterial isolates were obtained from four waste accumulation sites and taxonomically identified across 12 different genera using MALDI-TOF MS and 16S rRNA gene sequencing. This analysis revealed genera not previously reported as PU biodegraders, including Priesta, Dermacoccus, Gordonia, Micrococcus, Pseudarthrobacter, and Agromyces. The Bacillus cereus clade was the most prevalent group, followed by the Priestia megaterium clade and Achromobacter sp. Biodegradation assays revealed high variability among strains, with the most efficient degrading over 90% of Impranil DLN. Protease activity was the most frequently detected enzymatic function, followed by urease and esterase activities. However, no clear correlation was observed between enzymatic profiles and degradation efficiency. Selected strains were tested on polyether PU foam, revealing biodegradative activity, an uncommon observation for bacteria on such recalcitrant material. These findings contribute to our understanding of bacterial diversity and enzymatic mechanisms involved in PU biodegradation, as well as their potential applications in plastic waste bioremediation.