Identification and characterization of substrate- and product-selective nylon hydrolases

Area of Science:

• Biotechnology
• Polymer Science
• Enzymology

Background:

• Enzymes efficiently degrade natural polymers, but synthetic polyamide hydrolysis is limited.
• Nylon-degrading enzymes are scarce, hindering plastic recycling efforts.

Purpose of the Study:

• To synthesize and characterize a diverse panel of N-terminal nucleophile hydrolases for nylon degradation.
• To identify novel enzymes with substantial nylon hydrolase activity and selectivity.

Main Methods:

• Synthesized and screened 95 diverse N-terminal nucleophile hydrolases.
• Assessed nylon hydrolase activity and substrate selectivity (Nylon 6,6 vs. Nylon 6).
• Determined the crystal structure of a selective nylon hydrolase.

Main Results:

• Nearly 40% of tested enzymes showed significant nylon hydrolase activity.
• Identified novel hydrolases with activity comparable to known enzymes like NylC.
• Observed up to 20-fold higher product titers for Nylon 6,6 compared to Nylon 6 in some enzymes.
• No correlation found between enzyme phylogeny and nylon degradation activity.

Conclusions:

• The N-terminal nucleophile hydrolase superfamily harbors widespread potential for nylon hydrolysis.
• Newly discovered enzymes offer opportunities for plastic recycling and biodegradation.
• Structural analysis provides insights into enzyme selectivity and engineering potential.