PufH: A promising biocatalyst for the recycling and bioremediation of polyurethane foam waste

As the extensive use of polyurethane foam (PUF), the disposal of PUF waste poses significant environmental challenges. Enzyme-based recycling and bioremediation of PUF waste is regarded as a sustainable solution but still suffers from the lack of qualified enzymes. Here, a novel PUF-degrading bacterium, Pueribacillus sp. YX66, was isolated. An efficient polyurethane foam hydrolase (PufH), was identified from this strain, which showed less than 23 % sequence similarity to the previously reported PU depolymerases. Product analysis and molecular docking suggested that PufH specifically targeted the ester bonds within the soft segment of PUF. PufH exhibited remarkable activity against various commercial polyester-type PUFs, achieving a maximum depolymerization rate of 90 % within 48 h at 30 °C, significantly surpassing the performance of other PUF depolymerases. Moreover, PufH retained considerable activity at the temperature of 4–20 °C, enabling it to efficiently depolymerize PUF waste in soil within 14 days under ambient temperature. These findings underscore the potential of PufH as a promising biocatalyst in the recycling and bioremediation of PUF waste.