Defined Nylon Oligomers Enable Mechanistic Insight Into Enzymatic Polyamide Depolymerization

The remarkable progress in enzymatic polyester depolymerization has demonstrated the potential of biocatalysis for sustainable polymer recycling. In contrast, enzymatic polyamide (PA) degradation remains poorly understood, largely due to the lack of defined and accessible model substrates. Here, we report a robust solid-phase synthesis strategy for generating defined, monodisperse nylon-6 and nylon-6,6 oligomers with adjustable chain lengths. This approach enables the rapid and reproducible assembly of nylon oligomers that faithfully mimic the amide backbone of bulk polyamides while remaining soluble and analytically traceable. The resulting oligomer library provides a standardized set of substrates for screening and characterizing amidase activity, a class of enzymes whose substrate scope toward polyamides has not yet been systematically defined. As a proof of concept, we demonstrate the applicability of these model substrates using a representative amidase, revealing distinct chain length-dependent conversion profiles that illustrate the potential of this approach for mechanistic investigations into enzyme-nylon interactions. Notably, the degradation patterns observed for the oligomers closely match those obtained for bulk nylon materials, underscoring their relevance as realistic surrogates for polymer depolymerization. Overall, our synthetic strategy thus bridges a critical gap between polymer chemistry and enzymatic screening, providing a foundation for the rational exploration of biocatalytic polyamide depolymerization.