This ‘super enzyme’ takes us one step closer to getting rid of plastic landfills

A couple years ago, scientists had accidentally engineered an enzyme which eats plastic. However, they’ve been working on genetically engineering the enzyme to make it break plastic down faster—and they’ve finally got a breakthrough.

According to a press release from the University of Portsmouth, scientists have re-engineered and combined a plastic-eating enzyme named PETase with a second enzyme—MHETase. That enzyme ‘cocktail’ can digest plastic up to six times faster.

“Our first experiments showed that they did indeed work better together, so we decided to try to physically link them, like two Pac-men joined by a piece of string,” said Professor McGeehan, one of the scientists who engineered PETase.

How will the super enzyme work?

The enzymes were both derived from a bacterium discovered in Japan in 2016, which scientists found could break down polyethylene terephthalate (PET). Japanese researchers believe the bacterium evolved pretty recently, since plastics were not invented until the 1940s.

Usually PET takes hundreds of years to degrade in the environment. PETase can break it down in a few days. However, PETase alone is not yet fast enough to handle the tons of discarded PET bottles littering the planet.

The new super enzyme combines PETase and MHETase—a mixture of the two breaks down PET twice as fast as PETase on its own. Connecting the two enzymes can increase the speed by a further three times.

“Combining the plastic-eating enzymes with existing ones that break down natural fibres could allow mixed materials to be fully recycled,” added McGeehan.

Plastic waste is a huge problem in Malaysia. According to WWF-Malaysia, “bungkus” or “tapau” (takeaway) culture is one of the major contributors to the problem—but it is seen as a necessity. Plastic prevents edible items from going bad or being eaten by pests, which is a common problem due to the country’s hot and humid climate.

The latest development represents a huge stop towards using enzymes to recycle plastic and reduce plastic pollution. However, McGeehan underlined that the process is “still way too slow” to be commercially viable.

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