Environment

Fast-acting enzyme breaks down plastics in as little as 24 hours

Fast-acting enzyme breaks down...
Scientists have developed a new enzyme with an impressive ability to degrade PET plastics
Scientists have developed a new enzyme with an impressive ability to degrade PET plastics
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Scientists have developed a new enzyme with an impressive ability to degrade PET plastics
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Scientists have developed a new enzyme with an impressive ability to degrade PET plastics

The idea of deploying enzymes to break down plastic waste is gaining momentum through a string of breakthroughs demonstrating how they can do so with increasing efficiency, and even reduce the material to simple molecules. A new study marks yet another step forward, with scientists leveraging machine learning to engineer an enzyme that degrades some forms of plastic in just 24 hours, with a stability that makes it well-suited to large-scale adoption.

Scientists have been exploring the potential of enzymes to aid in plastics recycling for more than a decade, but the last six years or so has seen some significant advances. In 2016, researchers in Japan unearthed a bacterium that used enzymes to break down PET plastics in a matter of weeks. An engineered version of these enzymes, dubbed PETase, improved the performance further, and in 2020 we saw scientists develop an even more powerful version that digested PET plastics at six times the speed.

A team at the University of Texas set out to address some of the shortcomings of these enzymes so far. According to the scientists, the application of the technology has been held back by an inability to function well at low temperatures and different pH ranges, lack of effectiveness directly tackling untreated plastic waste, and slow reaction rates.

To resolve these problems, the team developed a machine learning model that could predict which mutations in a PETase enzyme would afford it these capabilities. This involved closely studying a range of PET plastic products, including containers, water bottles and fabrics, and then using the model to design and engineer a new and improved enzyme dubbed FAST-PETase (functional, active, stable and tolerant PETase).

This newly created enzyme proved superior at breaking down PET plastics at temperatures between 30 and 50 °C (86 and 122 °F) and at a range of pH levels. It was able to almost entirely degrade 51 different untreated PET products in the space of a week, and in some experiments broke down plastics in as little as 24 hours. The scientists also demonstrated a closed-loop PET recycling process, in which FAST-PETase was used to break down the plastics and then the recovered monomers were used to chemically reconstruct the material.

“When considering environmental cleanup applications, you need an enzyme that can work in the environment at ambient temperature," said study author Hal Alper. "This requirement is where our tech has a huge advantage in the future."

With the ability to quickly break down post-consumer plastic waste at low temperatures, the researchers believe they have landed on a technique that is portable, affordable and able to be adopted on an industrial scale. They have filed a patent for the technology and hope to see it put to use in landfills and polluted areas.

“The possibilities are endless across industries to leverage this leading-edge recycling process,” said Alper. “Beyond the obvious waste management industry, this also provides corporations from every sector the opportunity to take a lead in recycling their products. Through these more sustainable enzyme approaches, we can begin to envision a true circular plastics economy.”

The research was published in the journal Nature, while the video below offers an overview of the breakthrough.

Plastic-eating Enzyme Could Eliminate Billions of Tons of Landfill Waste

Source: University of Texas

12 comments
12 comments
claudio
how do you stop it from "eating" plastic when it shouldn't and not become a plague?
Catweazle
Shades of Michael Crichton's 1969 "Andromeda Strain" novel.
Jean Hohl
What to do with the excess amount of broken down substance, which will still be plastic? I was hoping this was about making plastic compostable and bio-available. Nope.
Alex Angel
@Jean Hohl - the monomers that go into plastics have other uses:
-ethylene is used as an anaesthetic, for rubber extraction, for welding, and in the petrochem industry
-propylene (and ethylene) are the two most often used intermediaries in the petrochem industry
-styrene is used in latex paint, alkyd paint, synthetic rubbers
-phenol is used as a disinfectant, antiseptic, and in plastics production

Hydrocarbons are always going to be hydrocarbons. If we can recycle them cheaply enough at the very least we can start removing them from the environment and remaking them into less toxic forms that are less likely to spread everywhere, and cheaply recycled industrial chemicals mean less oil wells.
Trylon
@claudio, enzymes are not self-replicating organisms. They're just chemicals. After a certain number of cycles, the enzyme will lose effectiveness. It won't overrun the world. It that weren't the case, we'd be in trouble because enzymes are all around us and part of our own biological processes.
guzmanchinky
What a fascinating step forward.
HoppyHopkins
If only I knew how to engineer bacteria. I would invest heavily in glass bottle and aluminum can manufacturers and turn it lose. I would make a bundle while protecting the environment
Dave
What appears to be lost in this discussion is the fact that the continued and growing use of plastics is infecting our oceans, our air, our fish, our snow, our bodies, etc. but industry is happy to tell us that some form of recycling will make it all better. Just as with global climate change, the petroleum industry wants to kick the can down the road until they have made all the money they can by emptying their oil and gas reserves. Band AIDS, Band AIDS, Band AIDS, as the patient bleeds to death. We really don’t want to confront reality. Maybe the future of plastic needs to be reduced and/or eliminated as much as possible.
GCG1000
"The idea of deploying enzymes to break down plastic waste is gaining momentum through a string of breakthroughs demonstrating how they can do so with increasing efficiency, and even reduce the material to simple molecules." I wonder what effects these 'plastic-eating enzymes' might have on humans, and the environment.
Caroline Judge
it sounds like a new industry that relies on us using and making... more plastic.
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