Enzymatic Nylon degradation: enzyme discoveries, engineering and challenges

Nylons are among the most widely produced synthetic polyamides, prized for their strength, versatility, and durability across textiles, packaging, and engineering applications. However, their petrochemical precursors and high energy demand make Nylon production a significant source of greenhouse gas emissions, highlighting the need for more efficient and circular solutions. Conventional recycling methods, either mechanical and chemical, achieve only partial material recovery and remain limited by efficiency, material degradation, and the need for costly sorting. Enzymatic depolymerization offers a promising low-energy and selective alternative, capable of recycling mixed feedstocks under mild conditions. While enzymatic recycling has advanced for polyesters such as polyethylene terephthalate (PET), the enzymatic breakdown of polyamides remains in its early stage. The discovery of Nylon hydrolases, notably NylC, revealed that microbial systems can evolve catalysts to degrade synthetic polyamides. However, enzymatic Nylon depolymerization is still inefficient, with typical reported yields below 1%. These low yields are due in part to the inherent structural complexity and semicrystallinity of Nylons but also demonstrate the need for additional effort on discovering, characterizing, and engineering Nylon hydrolases. This review examines the progress, challenges, and future directions of enzymatic Nylon recycling, outlining its potential role enabling mixed polymer waste to be used as a green feedstock for remanufacturing.