Skip to Content
Find More Like This
Return to Search

Enzymatic Degradation of PET Plastic

National Renewable Energy Laboratory

Contact NREL About This Technology

Technology Marketing Summary

Polyethylene terephthalate (PET), more commonly known as polyester, is one of the world’s most versatile and abundant, man-made plastics. However, as PET plastic moves into the world’s waste stream, its durable resistance to biodegradation has made it a primary, environmental concern - especially to ocean ecosystems where its accumulation is most recognizable and destructive. Attempts to protract PET’s useful lifespan by recycling have only been marginally successful, as chemical processing costs in recycling are much higher than the simpler, cheaper alternative of buying virgin PET for production.

Recently, scientists have discovered and characterized enzymes expressed by a PET-eating bacteria called Ideonella sakaiensis which holds great promise in solving the PET waste predicament. The bacterium secretes an enzyme called PETase that, when reacting with water, breaks PET plastic back down into its constituent base monomers. These include MHET [mono(2-hydroxyethyl) terephthalic acid], BHET [bis(2-hydroxyethyl) terephthalic acid], and the commodity chemicals ethylene glycol and terephthalic acid (TPA), which can be upcycled to polymers for additional use instead of being diverted to landfills.

Description

Seizing on the vast potential with this discovery, researchers at NREL and the University of Portsmouth have isolated and engineered a double mutant strain of PETase that yields specific degradation improvements to the original PETase enzyme. Furthermore, they have demonstrated this new strain’s improved capacity to break down PET’s semi-aromatic, polyester cousin polyethylene furanoate (PEF), which is a bioderived replacement to PET yielding improved barrier properties. With this new-found strain of PETase, the NREL team has demonstrated an effective, bio-based route to reproduce the base constituents of PET plastic and has furthermore enabled the potential for biological transformations to novel intermediates (e.g., ß-ketoadipate or muconate) and their conversion to new, high strength composites.

Benefits
  • Bio-based industrial plastic recycling and upcycling
  • Commodity chemical reproduction (EG and TPA)
  • Waste reduction
  • Environmental remediation
Applications and Industries
  • Plastic recycling
  • Waste treatment
  • Materials science and specialty products
  • Performance designed polymer design
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
ROI 18-54PrototypeAvailable05/21/201805/18/2018

Contact NREL About This Technology

To: Eric Payne<Eric.Payne@nrel.gov>