Scientists Fashion A Mutant Enzyme That Gives Superpowers To Plastic-Eating Bacterium

This enzyme, engineered to devour plastic at a higher rate, could one day be used to curb plastic pollution.

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A newly-created enzyme that scientists accidentally engineered in the lab turned out to have an unexpected effect, reveals a study published yesterday (April 17) in the journal Proceedings of the National Academy of Sciences.

The enzyme, a mutant version of the naturally occurring PETase found in a plastic-eating microbe, boosted the bug’s appetite and turned it ravenous, LiveScience reports.

According to Reuters, the mutant enzyme holds important potential and could become a valuable ally in managing the plastic pollution crisis.

The news couldn’t have come at a better time and has a stronger relevance in the context of Earth Day 2018, celebrated this weekend, on April 22.

Given that this year’s theme is centered around the fight against plastic pollution, as Earth Day Network informs, this latest research could offer a different approach to reducing plastic litter and pollution.

The study, conducted by researchers from the University of Portsmouth (UoP) in the U.K. together with colleagues from the University of South Florida in Tampa and the National Renewable Energy Laboratory (NREL) in Golden, Colorado, builds on the properties of a newfound plastic-eating bacterium called Ideonella sakaiensis.

This plastic-munching microbe was only discovered in 2016, notes LiveScience, in a waste recycling center in Japan. This bacterium was found to contain an enzyme later dubbed PETase, which helped the microbe digest plastic made of polyethylene terephthalate (PET).

Since Ideonella sakaiensis lived in the soil of a Japanese PET bottle-recycling facility, this durable type of plastic was its main food source, states a UoP news release.

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Because polyethylene terephthalate has only been around for about 70 years (it was patented in the 1940s), the scientists concluded that this newly-discovered bacterium must have evolved the enzyme so that it could consume PET.

Intrigued, the team wanted to analyze the PETase enzyme to gauge its properties and find out how it works. The researchers fiddled with it in the lab, adding sugar, spice, and everything nice (sounds familiar?). Thus, the super-enzyme was born!

According to John McGeehan, project co-leader and a professor of structural biology at UoP, the mutant enzyme came to be utterly by accident.

“Serendipity often plays a significant role in fundamental scientific research, and our discovery here is no exception,” McGeehan revealed in the news release.

He explained that his team “tweaked” the structure of PETase by adding some amino acids and ended up unleashing its inner Hulk.

“We’ve made an improved version of the enzyme better than the natural one already. That’s really exciting because that means that there’s potential to optimize the enzyme even further.”

The lab experiments enhanced the enzyme’s capacity to consume plastic, enabling it to work faster and, more importantly, to digest highly crystalline PET.

This bodes well for the future of antipollution strategies, considering that this material is used in virtually everything, from plastic bottles to synthetic fabrics to carpets and other household items, the study authors point out in their paper.

This breakthrough in enzyme research could help curb plastic pollution, notes a NREL-issued news release. The mutant enzyme that gives microbes the plastic munchies could be used to design bacteria that degrade PET bottles.

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Just like this lab-engineered enzyme, others could be tweaked to give them extra plastic-eating abilities as well. This would provide “new opportunities for bio-based plastics recycling,” the study authors show in their paper.

“The engineering process is much the same as for enzymes currently being used in bio-washing detergents and in the manufacture of biofuels,” explained McGeehan.

“The technology exists and it’s well within the possibility that in the coming years we will see an industrially viable process to turn PET and potentially other substrates like PEF, PLA, and PBS, back into their original building blocks so that they can be sustainably recycled,” he added.