Neural Network Discovers Enzyme That Degrades Polyurethane
Key Points
- Neural‑network‑driven protein design produced a new enzyme for polyurethane degradation.
- Polyurethane, used in foam cushioning, accounted for 22 million metric tons of production in 2024.
- The enzyme operates within an industrial recycling loop, converting polymer back to basic building blocks.
- Previous chemical methods like diethylene glycol required high temperatures and produced unusable waste.
- Enzyme‑based recycling could reduce reliance on incineration and lower plastic waste accumulation.
Researchers used advanced neural‑network‑driven protein design tools to create a new enzyme capable of breaking down polyurethane, a widely used polymer in foam cushioning and other products. The enzyme works within an industrial‑style recycling process, converting the polymer back into its basic building blocks for reuse. This breakthrough addresses the complex chemistry of polyurethane, which has resisted previous recycling efforts, and offers a potential pathway to reduce plastic waste and avoid hazardous incineration.
Background on Plastic Pollution and Polymer Diversity
Plastic pollution is often described as a single problem, but the reality is that it encompasses many challenges. Different plastics are made from distinct polymers, each held together by specific chemical bonds. Because of these variations, methods that work to break down one type of polymer may be incompatible with another.
Previous Enzyme Successes and Their Limits
Scientists have previously found enzymes that can degrade common plastics such as polyesters and polyethylene terephthalate (PET). While these discoveries represent important steps, they only provide partial solutions because they do not address the full spectrum of polymer chemistries found in the waste stream.
New Enzyme Targeting Polyurethane
Leveraging sophisticated protein‑design tools powered by neural networks, researchers have now engineered an enzyme specifically aimed at polyurethane. Polyurethane is the polymer most often used to make foam cushioning and is produced in massive quantities—22 million metric tons in 2024. The polymer’s structure includes a urethane bond, where a nitrogen atom is linked to a carbon that is double‑bonded to two oxygens, one of which connects to the rest of the polymer chain.
Polyurethane chains are frequently heavily cross‑linked, creating bulky, complex structures that make it difficult for enzymes to access and cleave the bonds. Traditional chemical methods, such as treatment with diethylene glycol, can partially break down these molecules but require elevated temperatures and generate a messy mixture of chemicals that cannot be easily reused, often leading to incineration as hazardous waste.
Industrial‑Scale Recycling Compatibility
The newly developed enzyme is compatible with an industrial‑style recycling process. In this process, the enzyme breaks the polymer down into its fundamental building blocks, which can then be fed back into the production of fresh polyurethane. This approach offers a closed‑loop solution that could reduce reliance on virgin feedstocks and limit the environmental impact of polyurethane waste.
Implications for Plastic Waste Management
The discovery demonstrates how artificial intelligence and advanced protein engineering can address longstanding challenges in plastic recycling. By targeting the specific chemistry of polyurethane, the enzyme opens a pathway to recycle a polymer that has historically been difficult to process, potentially decreasing the volume of plastic destined for landfills or incineration.