The diversity of PET degrading enzymes: A systematic review of sequence, structure, and function

Polyethylene terephthalate (PET) is one of the most significant plastic pollutants. Unlike other plastic polymers, PET can be degraded by PET-hydrolytic enzymes (PETases). Over the past two decades, numerous publications have reported the discovery, characterization, and engineering of PETases. This review thoroughly examines the sequence, structure, and functional diversity of naturally occurring PETases. To achieve this, we compiled data from 48 publications into a single table. The resulting dataset enabled us to contextualize previously reported features and shed light on the sequence–structure–function relationships of PETases. Finally, we review selected engineering campaigns and suggest future directions for the enzymatic recycling of PET under mesophilic and thermophilic conditions, aiming to understand the gaps to tackle the PET pollution crisis.