In a breakthrough that could mean wonders for plastic recycling and disposal, scientists have created a new combination of enzymes to break down plastic faster. This “super enzyme” as they call it, not only breaks down plastic six times faster than current methods, but is also more affordable and can work on a larger scale.
This is done by a team of researchers who re-engineered a plastic-eating enzyme in 2018. They have now combined it with a second enzyme to make it have major implications for the recycling of bottles, clothing, and all other commonly found waste.
In a study published in scientific journal PNAS on September 28, the researchers revealed that the “super-enzyme” was made by combining two separate enzymes—a plastic-eating enzyme named PETase and the new enzyme called MHETase. Using a technique that is commonly used in the biofuels industry, researchers effectively stitched the two enzymes’ DNA together to create one long chain which formed this new blend of enzymes. The two enzymes were derived from a bacterium discovered in Japan in 2016, which scientists found could break down polyethylene terephthalate (PET).
While this was the first time they combined two enzymes to break plastic, researchers believe that there is still a huge potential to tweak and make the enzymes work faster. “When we linked the enzymes, rather unexpectedly, we got a dramatic increase in activity,” said John McGeehan, a professor of structural biology at the University of Portsmouth, UK to The Guardian. “This is a trajectory towards trying to make faster enzymes that are more industrially relevant. But it’s also one of those stories about learning from nature, and then bringing it into the lab.”
Plastic pollution has always been one of the most pressing environmental issues, as their disposal has rapidly overwhelmed the world’s ability to deal with them. They take about 500 years to degrade in the ocean—if they do at all—and even then, much of it breaks down into microplastics that have been found in marine life, ocean water, and even in the guts of humans.
The super enzyme could have major benefits for recycling PET, which is the most common thermoplastic used in single-use drinks bottles and clothing. PET takes hundreds of years to degrade in the environment. With this, it can break down in a couple of days. Combining the plastic-eating enzymes with existing ones that break down natural fibres could allow mixed materials to be fully recycled, added McGeehan.