Exploring new galaxies: Perspectives on the discovery of novel PET-degrading enzymes

Polyethylene terephthalate (PET) is a widely used polyester due to its beneficial material properties and low cost. However, PET contributes significantly to the growing problem of plastic waste pollution. Enzymatic PET recycling has emerged as a promising alternative to conventional mechanical and chemical recycling methods. While many PET hydrolases – belonging to the α/β-hydrolase fold superfamily – have been discovered, the wild-type enzymes obtained from natural sources are not optimal for industrial conditions and need to be optimized through rational design or directed evolution to improve their efficiency and stability. This Perspective summarizes case studies of engineered PET hydrolases and proposes a workflow that tightly integrates a variety of in silico and high-throughput approaches for biochemical and structural characterization to accelerate the discovery of PET-degrading enzymes, also with novel structural scaffolds. These biocatalysts could be candidates for developing further innovative plastic recycling techniques.