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Accidental mutant enzyme sounds scary, but it could help eliminate plastic waste

Despite the public awareness drive that recycling has received in many states, the world still has a massive problem with polluting plastics. Right now there are millions of tons of unrecycled polyethylene terephthalate (PET) plastic bottles. Left alone, these will persist for hundreds of years before eventually decomposing. Researchers from the U.K.’s University of Portsmouth, the University of South Florida, and the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) have engineered an enzyme that’s capable of significantly speeding up that process — by digesting the world’s most common polluting plastics.

Their “PETase” enzyme was isolated from a bacterium found in a Japanese recycling plant in 2016. Following its discovery, the project’s research team set out to explore the properties of the enzyme, which led to them inadvertently creating a mutant version that outperforms its natural counterpart. The results reduce the length of time it takes to break down PET plastics to just a matter of days.

At present, the mutated version of PETase is around 20 percent more efficient than the naturally occurring enzyme, but this could be improved in the future. To examine exactly how the enzyme functions, the team recently used X-rays to generate an ultra-high resolution model of the enzyme at molecular level.

“We are currently in the early stages of optimizing this enzyme’s efficacy, however, our efforts are a very encouraging,” H. Lee Woodcock, associate professor in the Department of Chemistry at the University of South Florida, told Digital Trends. “We were able to clearly show that PETase is both a viable mechanism for plastic biodegradation, and that it is susceptible to engineering for improved activity. We already have plans in place to continue this work and envision a multi-fold improvement in the ability to recycle plastics in the near future.”

Woodcock said that there are no immediate plans to commercialize this biotechnology, although further research will absolutely take place. “We will have full access to NREL’s facilities that will facilitate the development of a pilot scale application,” Woodcock continued. “We will then work with industrial partners to move beyond the pilot scale.”

An article describing the work was recently published in the journal Proceedings of the National Academy of Sciences (PNAS).

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