Unveiling the enzymatic pathway of UMG-SP2 urethanase: insights into polyurethane degradation at the atomic level.

The recently discovered metagenomic urethanases UMG-SP1, UMG-SP2, and UMG-SP3 have emerged as promising tools to establish a bio-based recycling approach for polyurethane (PU) waste. These enzymes are capable of hydrolyzing urethane bonds in low molecular weight dicarbamates as well as in thermoplastic PU and the amide bond in polyamide employing a Ser-Ser -Lys triad for catalysis, similar to members of the amidase signature protein superfamily. Understanding the catalytic mechanism of these urethanases is crucial for enhancing their enzymatic activity and improving PU bio-recycling processes.

Structural and Functional Characterization of an Amidase Targeting a Polyurethane for Sustainable Recycling.

Global plastic production exceeded 400 million tons in 2022, urgently demanding improved waste management and recycling strategies for a circular plastic economy. While the enzymatic hydrolysis of polyethylene terephthalate (PET) has become feasible on industrial scales, efficient enzymes targeting other hydrolyzable plastic types, such as polyurethanes (PURs), are lacking. Recently, enzymes of the amidase signature (AS) family, capable of cleaving urethane bonds in a polyether-PUR analog and a linear polyester-PUR, have been identified.