Cutinase Enzymatic Degradation of Polyurethane Packaging Layers

The invention segments the multilayer packaging into individual polymer layers through selective enzymatic degradation. The cutinase enzyme specifically targets and degrades the polyurethane adhesive layer, separating it from the polyethylene and polypropylene layers. This allows each layer to be recovered in its original quality without the degradation that occurs in mechanical recycling, enabling the PE and PP layers to be reused for high-value applications.

The invention replaces the mechanical/chemical recycling system with a biological enzymatic system. Instead of using harsh chemicals and high energy input to break down polymers, the patent employs cutinase enzymes that catalyze the selective degradation of polyurethane adhesive layers under mild conditions (aqueous buffer, moderate temperature). This biological approach achieves polymer building blocks recovery with significantly reduced energy consumption and without the need for extreme conditions.

The invention changes the enzymatic parameters by selecting and optimizing specific cutinase enzymes (from fungi such as Aspergillus terreus, Penicillium expansum, and Trichoderma reesei) that have been shown to effectively degrade polyurethane adhesives in multilayer packaging. The patent optimizes degradation conditions including pH (6.5-8.0), temperature (30-50°C), and enzyme-to-substrate ratios to achieve high degradation efficiency (over 80% weight loss) for non-biodegradable polyurethanes used in packaging applications.