Scientists have created a new “super enzyme” that can break down plastic up to six times faster than the previous enzyme.
A team of researchers who previously redesigned a plastic-eating enzyme called PETase has now combined it with a second enzyme to speed up the process, according to a University of Portsmouth press release.
Superenzyme could have major implications for the recycling of polyethylene terephthalate (PET), the most common thermoplastic used in disposable beverage bottles, carpets and clothing.
PET has a lifespan of several hundred years until it degrades in the environment, but the new enzyme can break it down in a few days.
“We were actually quite surprised that it worked so well,” said John McGeehan, lead co-author and director of the Center for Enzyme Innovation at the University of Portsmouth, although he stressed that the process is “still too slow” to be commercially viable.
He told CNN that researchers have received funding for new experiments, and successful developments could mean that existing PET could be recycled instead of using fossil fuels to create new plastic.
How does the new enzyme work?
The super enzyme combines PETase and MHETase. A mixture of the two breaks down PET twice as fast as PETase does on its own and increases the speed of action of the two up to three times.
McGeehan used a diamond light source, a device that uses X-rays 10 billion times brighter than the Sun to see individual atoms and map the molecular structure of MHETase.
The researchers then succeeded in designing the new super enzyme by connecting MHETase and PETasse, effectively combining DNA enzymes to create a chain.
The technique is commonly used in the fuel industry, which uses enzymes to break down cellulases.
There are other methods of decomposing plastic
Plastic pollution is one of the most pressing environmental issues. A recent report by The Pew Charitable Trusts estimated that the volume of plastic entering the ocean could triple to 29 million metric tons per year by 2040.
He also said that there is no “single solution”, but that “an ambitious recycling strategy” can reduce 31-45% of plastic pollution.
In April, French company Carbios announced the publication of a study on its own PET-consuming enzyme, which will be tested at a demonstration plant near Lyon in 2021, according to a company press release.
Other possible solutions include the tiny wax worm, which can pass through plastics due to its intestinal bacteria.
Table worms could also contribute to the process. About 3,000-4,000 table worms can break down a cup of polystyrene coffee in about a week due to bacteria living in their gut.