Degradation of Polyester Polyurethane by Bacterial Polyester Hydrolases

Area of Science:

• Biotechnology
• Polymer Science
• Environmental Science

Background:

• Polyurethanes (PU) are prevalent synthetic polymers contributing to global plastic waste.
• Petrochemical-based raw material limitations necessitate innovative recycling and degradation methods for PU.

Purpose of the Study:

• To investigate the enzymatic degradation of polyester polyurethanes (PU) using various polyester hydrolases.
• To assess the efficiency and substrate affinity of enzymes like TfCut2 and LC cutinase (LCC) on specific PU materials.

Main Methods:

• Turbidimetric assays were employed to analyze hydrolysis rates of Impranil DLN by polyester hydrolases.
• Weight loss measurements, gel permeation chromatography, scanning electron microscopy, and Fourier transform infrared spectroscopy were used to evaluate degradation of thermoplastic PU (TPU).

Main Results:

• TfCut2 and Tcur0390 exhibited the highest hydrolysis rates for Impranil DLN, with TfCut2 showing superior substrate affinity.
• Enzymatic degradation by four polyester hydrolases resulted in significant weight loss (up to 4.9%) in Elastollan B85A-10 and C85A-10 TPUs.
• Degradation preferentially targeted larger polymer chains, causing surface erosion and ester bond cleavage.

Conclusions:

• Polyester hydrolases demonstrate potential for the degradation and recycling of polyester polyurethanes.
• Enzymatic degradation offers a promising avenue for addressing PU plastic waste and reducing reliance on petrochemicals.