AI-Guided Discovery: 24 Enzymes Identified That Could Make Polyurethane Packaging Recyclable

AI Pinpoints Enzymes That Might Break Down Tough Packaging Foam

Researchers at Beijing University and partner institutions have used machine learning to screen enzyme databases and identify candidates that could degrade thermoset polyurethanes (PUs) — the stubborn foams commonly used in product packaging and shipping.

The team applied deep-learning models to predict which enzymes can hydrolyze the strong chemical bonds that make many PUs hard to recycle. According to Packaging Insights, these foams are widely used in shipping applications, and Our World in Data estimates that shipping materials account for roughly 40% of global plastic waste.

“PU, with an annual global consumption of 22 million metric tons in 2024, constitutes the second largest category of hydrolyzable plastics,” the researchers wrote in a summary of their work published in a Science abstract.

The algorithm flagged 24 enzyme candidates that appear capable of attacking the chemical bonds in problematic PUs. Several of the enzymes were previously misclassified in public databases; reanalysis suggests they possess traits useful for polymer degradation. The study emphasizes how deep learning can accelerate discovery of industrially relevant biocatalysts and help overcome a major barrier in polyurethane recycling.

Why This Matters

Polyurethane foams are durable by design, which makes them difficult to break down and recycle. If any of these candidate enzymes can be validated and optimized in the lab, they could enable new recycling pathways for a material that is currently often landfilled or incinerated.

The Beijing group says it will continue laboratory validation and optimization of the candidates to confirm activity, improve efficiency, and evaluate practical applications at scale. The researchers note that advancing enzyme-based recycling will both expand scientific understanding of enzyme functions and support development of biocatalysts for industrial challenges.

Broader Context and Practical Tips

Biological solutions are only one piece of the puzzle. Scientists elsewhere have also found organisms that can digest synthetic materials — for example, a Kenyan insect reported to consume Styrofoam and studies of waxworms that may degrade other plastics. Still, reducing single-use plastics remains a simple, effective step: consumers can cut waste and save money by choosing reusable items such as water bottles.

Environmental groups warn that common plastics can take decades to centuries to break down and fragment into microplastics, which have been detected in ecosystems and human tissues. Stanford Medicine has reported microplastics in multiple organs and bodily fluids from early life stages; as one expert put it, "We're born pre-polluted."

Next steps: The promising enzyme candidates will undergo laboratory testing to verify activity against real-world polyurethane materials and to assess their potential for industrial recycling processes.