Scientists Create A New Enzyme Cocktail That Digests Plastic Six Times Faster

A group of scientists has paired a plastic-eating enzyme called PETase with another enzyme to create a cocktail that can digest plastic up to six times faster than previously possible. The team used a second enzyme found in the same plastic consuming bacterium that has been combined with PETase to speed up the breakdown of the plastic. PETase can break down polyethylene terephthalate and has now been combined with a second enzyme called MHETase.

PET is the most common thermoplastic and is used to make single-use drink bottles, clothing, and carpet. If the material is left alone, it takes hundreds of years to break down in the environment. However, when PETase is used to break the bottles down, the hundreds of years needed for the PET to breakdown naturally is shortened to days.

When the enzyme was initially discovered, it created a revolution in plastic recycling, creating a potential low-energy solution to reduce plastic waste. Researchers working on PETase in the laboratory made it about 20 percent faster at breaking down the plastic than the past enzyme process. Combining it with MHETase generated significantly larger improvements by doubling the breakdown of PET.

Prof. John McGeehan co-led the team behind the new enzyme and is also the scientist who engineered PETase. He said that PETase attacks the surface of plastics while MHETase "chops things up further." The enzymes were combined by physically linking them "like to Pac-men joined by a piece of string." Combined, the two enzymes are about three times faster than each enzyme used individually.

The two enzymes are able to digest the plastic, returning it to its original building blocks. The process allows the plastics to be made and reused endlessly, reducing reliance on fossil fuels such as oil and gas.