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A suspected plastic-eating superzyme could be a step forward in finding ways to tackle the pollution crisis, scientists have said.
The enhanced protein comprises two enzymes produced by a type of bacteria that feed on plastic bottles, known as Ideonella sakaiensis.
Professor John McGeehan, director of the Center for Enzyme Innovation at the University of Portsmouth, said that unlike natural degradation, which can take hundreds of years, the superzyme can turn plastic into its original materials, or building blocks, in just a few days.
He told the Palestinian Authority news agency: “Currently, we get those building blocks from fossil resources like oil and gas, which is really unsustainable. But if we can add enzymes to plastic waste, we can start breaking it down into a matter of days.”
The process would allow plastics “to be manufactured and reused endlessly, reducing our dependence on fossil resources,” he added.
In 2018, Professor McGeehan and his team accidentally discovered a engineered version of an enzyme, PETase, capable of breaking down plastic in days.
For their study, published in the journal Proceedings of the National Academy of Sciences, the professor and his team mixed PETase with the second enzyme, MHETase, and found that “the digestion of plastic bottles literally doubled.”
Professor McGeehan, one of the study’s authors, said: “This allowed us to create a super enzyme six times faster than the original PETase enzyme alone.
“This is quite a significant advance because the plastic that ends up in our oceans today will take hundreds of years to break down naturally. Over time, through sunlight and wave action, it will start to break down into pieces each time. smaller and we will end up with microplastics, a serious problem for organisms that live in the environment. “
Tests showed that this superenzyme was capable of breaking down a type of plastic used in soft drink and fruit juice packaging, known as PET (polyethylene terephthalate).
Although it is said to be highly recyclable, discarded PET persists for hundreds of years in the environment before degrading. In addition to PET, the superenzyme also works with PEF (polyethylene furanoate), a sugar-based bioplastic used in the manufacture of beer bottles. Professor McGeehan added, however, that the superzyme could not break down other types of plastic.
In the next part of their studies, the researchers will look for ways to further accelerate the decomposition process, so that the technology can be adapted for commercial purposes.
Professor McGeehan said: “The faster we can produce the enzymes, the faster we can break down the plastic and the more commercially viable it will be.”
