The breakthrough, spurred by the discovery of plastic-eating bugs at a Japanese dump, could help solve the global plastic pollution crisis

Scientists have created a mutant enzyme that breaks down plastic drinks bottles – by accident. The breakthrough could help solve the global plastic pollution crisis by enabling for the first time the full recycling of bottles.

The new research was spurred by the discovery in 2016 of the first bacterium that had naturally evolved to eat plastic, at a waste dump in Japan. Scientists have now revealed the detailed structure of the crucial enzyme produced by the bug.

The international team then tweaked the enzyme to see how it had evolved, but tests showed they had inadvertently made the molecule even better at breaking down the PET (polyethylene terephthalate) plastic used for soft drink bottles. “What actually turned out was we improved the enzyme, which was a bit of a shock,” said Prof John McGeehan, at the University of Portsmouth, UK, who led the research. “It’s great and a real finding.”

The mutant enzyme takes a few days to start breaking down the plastic – far faster than the centuries it takes in the oceans. But the researchers are optimistic this can be speeded up even further and become a viable large-scale process.

“What we are hoping to do is use this enzyme to turn this plastic back into its original components, so we can literally recycle it back to plastic,” said McGeehan. “It means we won’t need to dig up any more oil and, fundamentally, it should reduce the amount of plastic in the environment.”

About 1m plastic bottles are sold each minute around the globe and, with just 14% recycled, many end up in the oceans where they have polluted even the remotest parts, harming marine life and potentially people who eat seafood. “It is incredibly resistant to degradation. Some of those images are horrific,” said McGeehan. “It is one of these wonder materials that has been made a little bit too well.”

However, currently even those bottles that are recycled can only be turned into opaque fibres for clothing or carpets. The new enzyme indicates a way to recycle clear plastic bottles back into clear plastic bottles, which could slash the need to produce new plastic.

“You are always up against the fact that oil is cheap, so virgin PET is cheap,” said McGeehan. “It is so easy for manufacturers to generate more of that stuff, rather than even try to recycle. But I believe there is a public driver here: perception is changing so much that companies are starting to look at how they can properly recycle these.”

Quick guide What are PET plastics? Show Hide PET – or polyethylene terephthalate – is the most common plastic used for soft drinks bottles. This is because it is lightweight, shatterproof, easy to mould and colour and cheap to produce. The key raw material is oil. PET in a different form is also used in clothing, where it is called polyester. The estimated recycling rates for PET bottles vary significantly around the world, from 31% in the US, to 48% in Europe, 72% in Japan and 90% in India, where rag pickers collect the bottles to sell to waste traders. Deposit return schemes are very successful in some countries. But, globally, many bottles end polluting the environment.

PET bottles that are recycled have to be cleaned, sorted by colour, then shredded and dried to produce PET flakes. These can then be used to make new plastic but, due to impurities, it is not usually possible to make new, clear PET bottles. Instead, recycled bottles are mostly used to make polyester fibres.



The new research, published in the journal Proceedings of the National Academy of Sciences, began by determining the precise structure of the enzyme produced by the Japanese bug. The team used the Diamond Light Source, near Oxford, UK, an intense beam of X-rays that is 10bn times brighter than the sun and can reveal individual atoms.

The structure of the enzyme looked very similar to one evolved by many bacteria to break down cutin, a natural polymer used as a protective coating by plants. But when the team manipulated the enzyme to explore this connection, they accidentally improved its ability to eat PET.

“It is a modest improvement – 20% better – but that is not the point,” said McGeehan. “It’s incredible because it tells us that the enzyme is not yet optimised. It gives us scope to use all the technology used in other enzyme development for years and years and make a super-fast enzyme.”

Play Video 3:32 Welcome to Australia's plastic beach – video

Industrial enzymes are widely used in, for example, washing powders and biofuel production, They have been made to work up to 1,000 times faster in a few years, the same timescale McGeehan envisages for the plastic-eating enzyme. A patent has been filed on the specific mutant enzyme by the Portsmouth researchers and those from the US National Renewable Energy Laboratory in Colorado.

One possible improvement being explored is to transplant the mutant enzyme into an “extremophile bacteria” that can survive temperatures above 70C, at which point PET changes from a glassy to a viscous state, making it likely to degrade 10-100 times faster.

Earlier work had shown that some fungi can break down PET plastic, which makes up about 20% of global plastic production. But bacteria are far easier to harness for industrial uses.

Other types of plastic could be broken down by bacteria currently evolving in the environment, McGeehan said: “People are now searching vigorously for those.” PET sinks in seawater but some scientists have conjectured that plastic-eating bugs might one day be sprayed on the huge plastic garbage patches in the oceans to clean them up.

Microplastic pollution in oceans is far worse than feared, say scientists Read more

“I think [the new research] is very exciting work, showing there is strong potential to use enzyme technology to help with society’s growing waste problem,” said Oliver Jones, a chemist at RMIT University in Melbourne, Australia, and not part of the research team.

“Enzymes are non-toxic, biodegradable and can be produced in large amounts by microorganisms,” he said. “There is still a way to go before you could recycle large amounts of plastic with enzymes, and reducing the amount of plastic produced in the first place might, perhaps, be preferable. [But] this is certainly a step in a positive direction.”



Prof Adisa Azapagic, at the University of Manchester in the UK, agreed the enzyme could be useful but added: “A full life-cycle assessment would be needed to ensure the technology does not solve one environmental problem – waste – at the expense of others, including additional greenhouse gas emissions.”

•This article was amended on 17 April 2018 to make clear that PET becomes viscous above 70C. Its melting point is above 250C.</s>ST. LOUIS, April 17, 2018 /PRNewswire/ -- Mathelin Bay Associates LLC will officially launch its online blockchain enabled global plastics marketplace PlastiTrail.com on May 7, 2018, in Orlando, Florida, at the start of NPE 2018, North America's largest plastics trade show (Booth S11022).

Mathelin Bay, an international plastics industry consulting firm serving plastics industry processors and investors, designed PlastiTrail.com on a blockchain platform in order to break down some of the current barriers preventing potential buyers and sellers of plastics resins, plastic compounds and plastic scrap in the $1 trillion-plus global plastics market from locating and contracting with trustworthy trading partners in their own country or in foreign markets. Plastics sales contracts made on PlastiTrail.com will be virtually impossible to alter after the fact in the event of questions about contract representations or the quality or fitness for use of particular plastics shipments. The origin of individual plastics shipments will be easier to trace, which can support the sales of more higher-value-added plastics. And secure, tamper-resistant documents can be used in support of plastics origin requirements for government regulations such as the California Rigid Plastic Packaging Container Act's provision for a minimum percentage of post-consumer recycled plastics content in various plastic products sold in California.

Phillip Karig, Mathelin Bay's managing director, said that "PlastiTrail.com is all about building trust and transparency between plastics buyers and sellers. The PlastiTrail blockchain will provide a secure record of plastics contracts entered into on the marketplace, including any certifications, technical data sheets, photographs and other representations which will be duplicated, published, stored and encrypted at multiple locations around the world.

"Beyond contract representations stored in the blockchain, secure and encrypted information about the origin of plastics resins, compounds or scrap will allow plastics distributors and brokers to potentially sell more name brand and less generic plastics. An additional benefit, especially for plastics sellers with limited resources to market their products locally or in foreign markets is PlastiTrail.com's supplier review system that will allow plastics suppliers the opportunity to earn high ratings for their sales transactions with customers on the marketplace."</s>A couple of years ago, scientists discovered an enzyme in a waste recycling center in Japan that digests plastic. During a recent experiment to understand how this enzyme works, scientists accidentally created a mutated version that breaks down plastic even better than the one found in nature. The discovery could go a long way in reducing plastic waste, particularly from water bottles.

Progress in science is driven by very deliberate and calculated work, but every once in a while a happy accident occurs that enables us to take a major step forward.

A new paper published in Proceedings of the National Academy of Sciences is a perfect case in point. Researchers from the University of Portsmouth and the US Department of Energy’s National Renewable Energy Laboratory were conducting an experiment to see how a plastic-munching enzyme does its work (an enzyme is a chemical byproduct produced by living organisms). When they tweaked its physical structure, the scientists inadvertently created an enzyme that is 20 percent more efficient at breaking down plastic than the version found in nature.

“Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception,” said John McGeehan, lead author of the new study, in a statement. “Although the improvement is modest, this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics.”

No doubt, since plastics first became popular in the 1960s, the waste produced by these products has gone from a minor headache to a throbbing migraine. Plastic waste exists practically everywhere, from landfill sites and state parks, through to ocean garbage patches and even the deepest parts of the sea. Millions of tons of plastic bottles, for instance, now litter the Earth, and they take hundreds of years to degrade.

Finding ways to accelerate the degradation process has proved challenging, but the 2016 discovery of an enzyme that exclusively eats Polyethylene terephthalate (PETs)—the plastic found in water bottles—offered hope. This strange enzyme, called PETase, comes from the bacteria Ideonella sakaiensis, and it breaks PETs down to terephthalic acid and ethylene glycol in a process that takes days rather than centuries. Because these plastics have only existed since the 1940s, McGeehan’s team figured the enzyme evolved only recently, likely in the Japanese waste recycling facility in which it was found. For the new study, the researchers wanted to determine how the enzyme evolved and to see if it could be improved upon.

Using the synchrotron at the UK’s Diamond Light Source, the researchers managed to solve the crystal structure of the PETase. This machine uses intense beams of x-rays that contain billions of times more photons than the x-rays that come from the Sun, allowing researchers to see the structure of individual atoms in three dimensions.

To visually see how this enzyme interacts with plastic, the researchers modeled its newly derived 3D structure in a computer. They were able to see that PETase was visually similar to an enzyme called cutinase, which is found in fungi that infects plants. But it featured important differences, including an exposed active area that links well with plastics. To test the theory that PETase evolved in an environment rich with PETs, the researchers mutated the PETase’s active site to make it more cutinase-like. And that’s when the researchers stumbled upon their superior plastic-munching enzyme.



In addition to being able to break down PETs, the researchers confirmed that the mutated enzyme was capable of digesting polyethylene furandicarboxylate (PEF), a bio-based substitute for PET plastics that could eventually replace some glass beer bottles.

The researchers will now continue their work to see if the enzyme can be upscaled to industrial levels, and break down plastic even faster. Importantly, the researchers are hoping that a circular recycling system can be devised whereby plastic can be reconstituted back into plastic, easing the burden on plastic production and oil extraction.

“I think this is very exciting work,” Oliver Jones, a chemist at RMIT University who was not involved in the study, said in a statement. “Enzymes are non-toxic, biodegradable, and can be produced in large amounts by microorganisms (bacteria and fungi). Although most people don’t know it, enzymes already help us out in many areas of everyday life such biological laundry detergents ​and in the food, leather, and textiles industries.”

It may be a while yet before we see this mutated enzyme used at an industrial scale, but it’s certainly a step in that direction.

[Proceedings of the National Academy of Sciences]</s>Scientists in Britain and the United States say they have engineered a plastic-eating enzyme that could in future help in the fight against pollution.

The enzyme is able to digest polyethylene terephthalate, or PET — a form of plastic patented in the 1940s and now used in millions of tons of plastic bottles. PET plastics can persist for hundreds of years in the environment and currently pollute large areas of land and sea worldwide.

Researchers from Britain's University of Portsmouth and the U.S. Department of Energy's National Renewable Energy Laboratory made the discovery while examining the structure of a natural enzyme thought to have evolved in a waste recycling centre in Japan.

Finding that this enzyme was helping a bacteria to break down, or digest, PET plastic, the researchers decided to "tweak" its structure by adding some amino acids, said John McGeehan, a professor at Portsmouth who co-led the work.

This led to a serendipitous change in the enzyme's actions — allowing its plastic-eating abilities to work faster.

"We've made an improved version of the enzyme better than the natural one already," McGeehan told Reuters in an interview. "That's really exciting because that means that there's potential to optimise the enzyme even further."

The team, whose finding was published on Monday in the Proceedings of the National Academy of Sciences journal, is now working on improving the enzyme further to see if they can make it capable of breaking down PET plastics on an industrial scale.

"It's well within the possibility that in the coming years we will see an industrially viable process to turn PET, and potentially other [plastics], back into their original building blocks so that they can be sustainably recycled," McGeehan said.

Independent scientists not directly involved with the research said it was exciting, but they cautioned that the enzyme's development as a potential solution for pollution was still at an early stage.
• Plastic bags question: what to do with all our junk?

"Enzymes are non-toxic, biodegradable and can be produced in large amounts by microorganisms," said Oliver Jones, a expert in analytical chemistry at Royal Melbourne Institute of Technology University.

"There is strong potential to use enzyme technology to help with society's growing waste problem by breaking down some of the most commonly used plastics."

Douglas Kell, a professor of bioanalytical science at Manchester University, said further rounds of work "should be expected to improve the enzyme yet further."

"All told, this advance brings the goal of sustainably recyclable polymers significantly closer," he added.</s>Two scientists have accidentally stumbled upon an organic enzyme that can eat some of our worst polluting plastics, providing a possible solution to what is arguably one of the world’s biggest environmental problems. Polythylene terephthalate or PET is one of the worst man-made plastics for recycling taking hundreds of years to break down into the environment. Yet despite this, the amount of waste plastic in the oceans could treble in the next 10 years unless urgent action is taken to curb the problem. It’s estimated that a frankly staggering 12 million tonnes of plastic rubbish is dumped into the oceans every single year.

Professor John McGeehan and his team from the University of Portsmouth along with Dr Gregg Beckham from the US Department of Energy’s National Renewable lab had both been trying to find a way of combating this plastic pest when they stumbled on the solution. The team had been looking originally at another enzyme called PETease which had evolved in a waste recycling centre in Japan. PETease was a remarkable organism, having come into existence only since PET was created in the 1940s. To analyse PETease, the teams employed the Diamond Light Source in Oxfordshire. This ultra-powerful microscope is able to fire intense X-rays 10 billion times brighter than the Sun, giving the scientists the ability to examine the 3D atomic structure of the enzyme.

Upon inspecting the model the teams found it looked very similar to another enzyme known as a cutinase. To test their theory they then mutated the PETease to make it look even more like a cutinase. It was then that the serendipitous moment happened. The team discovered that they had inadvertently made the enzyme better than its original form at digesting the plastic. “Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception,” Professor McGeehan said.

The team will now work to improve the enzyme even further with Professor McGeehan confident that we could finally have a viable recycling solution for these plastics within just a few years. Professor McGeehan said: “The engineering process is much the same as for enzymes currently being used in bio-washing detergents and in the manufacture of biofuels – 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 they can be sustainably sustained.”</s>Scientists have developed an enzyme that can break down plastic bottles — and the creation was a happy accident.

An international team of researchers made the discovery while studying a natural enzyme that was believed to have evolved to eat plastic in a waste recycling center in Japan.

The researchers modified the enzyme to analyze its structure, but instead accidentally engineered an enzyme that was even better at breaking down the plastic used for soft drink bottles, polyethylene terephthalate or PET.

"Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception," said lead researcher, professor John McGeehan of the University of Portsmouth in the U.K., in a statement.

"Although the improvement is modest, this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics."

The new enzyme starts breaking down the plastic in just a few days. But the researchers are working to improve the enzyme so it breaks down plastics even more quickly. They say the discovery could offer a solution for millions of tons of plastic bottles made of PET that linger in the environment. Plastic takes more than 400 years to degrade.

About 1 million plastic bottles are bought around the world every minute. (Photo: Vladimir Mucibabic/Shutterstock)

One million plastic bottles are bought around the world every minute, and the number will likely increase by another 20 percent by 2021, reports The Guardian, citing statistics from consumer market research company Euromonitor International.

Of the 8.3 million metric tons of plastic that have been produced so far, a mere 9 percent of it has been recycled, researchers in a 2017 study estimated. The vast majority of it — 79 percent — is sitting in landfills or in the environment, much of it floating in our oceans. "If current production and waste management trends continue, roughly 12 [billion metric tons] of plastic waste will be in landfills or in the natural environment by 2050," said the researchers.

"Few could have predicted that since plastics became popular in the 1960s, huge plastic waste patches would be found floating in oceans, or washed up on once pristine beaches all over the world," McGeehan said.

"We can all play a significant part in dealing with the plastic problem, but the scientific community who ultimately created these 'wonder-materials' must now use all the technology at their disposal to develop real solutions."

The story behind the discovery

The new research, published in the journal Proceedings of the National Academy of Sciences, began with investigators working to figure out the exact structure of the enzyme that evolved in Japan. Researchers collaborated with scientists at the Diamond Light Source synchrotron science facility, using an intense beam of X-rays that is 10 billion times brighter than the sun and acts like a microscope to reveal individual atoms.

The team found that the enzyme looked similar to one that breaks down cutin, a waxy, protective coating for plants. When they mutated the enzyme to study it, they accidentally improved its ability to eat PET plastic.

"The engineering process is much the same as for enzymes currently being used in bio-washing detergents and in the manufacture of biofuels — 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 ... back into their original building blocks so that they can be sustainably recycled," McGeehan said.</s>Scientists from Portsmouth University and the Diamond Light Source are part of an international team that has engineered an enzyme with the potential to digest certain plastics.

The discovery could lead to a recycling solution for the millions of tonnes of plastic bottles made of polyethylene terephthalate (PET), which will persist for hundreds of years in the environment.

The research was led by teams at the Portsmouth University and the US Department of Energy’s National Renewable Energy Laboratory (NREL) and is published in Proceedings of the National Academy of Sciences (PNAS).

Portsmouth University’s Prof John McGeehan and Dr Gregg Beckham at NREL solved the crystal structure of PETase – an enzyme that digests PET- and used this 3D information to understand how it works. During this study, they unintentionally engineered an enzyme that is even better at degrading the plastic than the one that has already evolved.

The researchers are now working on improving the enzyme so that it can be used industrially to break down plastics in a fraction of the time.

Prof McGeehan, director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth, said: “We can all play a significant part in dealing with the plastic problem, but the scientific community who ultimately created these ‘wonder-materials’, must now use all the technology at their disposal to develop real solutions.”

The researchers made the breakthrough when they were examining the structure of a natural enzyme which is thought to have evolved in a waste recycling centre in Japan, allowing a bacterium to degrade plastic as a food source.

PET was patented as a plastic in the 1940s, so the team set out to determine how the enzyme evolved and if it might be possible to improve it. The goal was to determine its structure, but they ended up engineering an enzyme which was even better at breaking down PET plastics.

“Although the improvement is modest, this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics,” said Prof McGeehan.

The research team can now apply the tools of protein engineering and evolution to continue to improve it.

Portsmouth University and NREL collaborated with scientists at the Diamond Light Source. Using beamline I23, an ultra-high-resolution 3D model of the PETase enzyme was generated.

With help from the computational modelling scientists at the University of South Florida and Brazil’s University of Campinas, the team discovered that PETase looks very similar to a cutinase (an enzyme it had likely evolved from), but it has some unusual features including a more open active site cleft that is able to accommodate man-made rather than natural polymers. These differences indicated that PETase may have evolved in a PET-containing environment to enable the enzyme to degrade PET. To test that hypothesis, the researchers mutated the PETase active site to make it more like a cutinase.

The researchers found that the PETase mutant was better than the natural PETase in degrading PET. The enzyme can also degrade polyethylene furandicarboxylate (PEF), a bio-based substitute for PET plastics that is being hailed as a replacement for glass beer bottles.

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

CLICK HERE FOR MORE ENGINEERING NEWS</s>Solving the problem of plastic waste has flown up the agenda since Sir David Attenborough's documentary showed it killing the world's oceans.

There are calls for plastic free aisles in supermarkets, a plastic bottle deposit scheme has become a hot topic - and reusable coffee cups got handed out to ministers attending Cabinet .

And now an accidental discovery could be a big help in reducing our mountains of plastic rubbish.

British researchers hope an engineered enzyme could be key - but only discovered it while investigating its natural counterpart.

Tests showed the lab-made mutant had a supercharged ability to break down polyethylene terephthalate (PET), one of the most popular forms of plastic used in the food and drinks industry.

Bottles made from PET are used to package 70% of soft drinks, fruit juices and mineral waters sold in shops and supermarkets, according to the British Plastics Federation.

Although it is said to be highly recyclable, discarded PET persists for hundreds of years in the environment before it degrades.

Where the idea came from

The new research sprang from the discovery of bacteria in a Japanese waste recycling centre that had evolved the ability to feed on plastic.

The bugs used a natural enzyme called PETase to digest PET bottles and containers.

While probing the molecular structure of PETase, the UK team inadvertently created a powerful new version of the protein.

Working with US colleagues, University of Portsmouth scientists subjected PETase to intense X-ray beams at the Diamond Light Source synchrotron facility in Harwell, Oxfordshire.

X-rays 10 billion times brighter than the sun are generated at the facility by accelerating electrons around a circular tunnel. The X-rays can be used to reveal the fine structure of materials and biomolecules, down to the level of individual atoms.

Using the PETase blueprint provided by the Diamond Light Sources, the scientists re-engineered an active region of the molecule. The result was a mutant protein with an enhanced ability to attack plastic.

In addition to digesting PET, the new enzyme was also capable of degrading polyethylene furandicarboxylate (PEF), a bio-based form of plastic being hailed as a replacement for glass beer bottles.

Lead scientist Professor John McGeehan, from the University of Portsmouth, said: "Serendipity often plays a significant role in fundamental scientific research, and our discovery here is no exception.

"Although the improvement is modest, this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics.

"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 (plastic) substrates like PEF, PLA and PBS back to their original building blocks, so that they can be sustainably recycled."

The findings are reported in the journal Proceedings of the National Academy of Sciences.

Prof McGeehan, director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth, said: "Few could have predicted that since plastics became popular in the 1960s huge plastic waste patches would be found floating in oceans, or washed up on once pristine beaches all over the world.

"We can all play a significant part in dealing with the plastic problem, but the scientific community who ultimately created these 'wonder-materials' must now use all the technology at their disposal to develop real solutions."</s>Researchers in the US and Britain have engineered a plastic-eating enzyme to speed up its abilities to digest plastic.

Scientists from Britain's University of Portsmouth and the US Department of Energy's National Renewable Energy Laboratory "tweaked" the structure of the naturally-occurring enzyme after they found that it was helping a bacteria to break down, or digest, plastic used to make bottles.

"We've made an improved version of the enzyme better than the natural one already," said John McGeehan, a professor at Portsmouth who co-led the work. "That's really exciting because that means that there's potential to optimize the enzyme even further."

Read more: Krill can digest ocean plastics: 'That is certainly not good news at all'

The engineered enzyme could in future help in the fight against pollution caused by plastics, which can persist for hundreds of years in the environment and currently pollute large areas of land and sea worldwide.

The team of scientists is now working on improving the enzyme further to see if they can make it capable of breaking down plastics on an industrial scale.

"It's well within the possibility that in the coming years we will see an industrially viable process to turn PET (polyethylene terephthalate — a form of plastic used in plastic bottles), and potentially other (plastics), back into their original building blocks so that they can be sustainably recycled," McGeehan said.

Read more: Is marine plastic pollution a threat to human health?

The enzyme — called PETase — was discovered in Japan a few years ago when scientists found that it was helping a bacterium break down plastic.

Japanese researchers believe the bacterium — Ideonella sakaiensis — evolved fairly recently in a waste recycling center, since plastics were not invented until the 1940s.

Ideonella sakaiensis feeds exclusively on PET plastic, widely used in bottles.

Each evening at 1830 UTC, DW's editors send out a selection of the day's hard news and quality feature journalism. You can sign up to receive it directly here.</s>WASHINGTON (CBSMiami) – Scientists have accidentally developed a plastic-eating enzyme that may be used to combat one of the world’s worst pollution problems.

Researchers from Britain’s University of Portsmouth and the US Department of Energy’s National Renewable Energy Laboratory (NREL) made the discovery while examining the structure of a natural enzyme found in a waste recycling center a few years ago in Japan.

They say the enzyme, Ideonella sakaiensis 201-F6, is able to “eat” polyethylene terephthalate, PET, which was patented as a plastic in the 1940s and is used in millions of tons of plastic bottles.

Their aim was to study its structure, but they accidentally engineered an enzyme which was even better at breaking down PET plastics.

“We hoped to determine its structure to aid in protein engineering, but we ended up going a step further and accidentally engineered an enzyme with improved performance at breaking down these plastics,” said NREL’s lead researcher Gregg Beckham.

The discovery could result in a recycling solution for millions of tons of plastic bottles made of PET, which currently persists for hundreds of years in the environment, the University of Portsmouth said on its website.

“Serendipity often plays a significant role in fundamental scientific research and our discovery here is no exception,” said Professor John McGeehan, director of the Institute of Biological and Biomedical Sciences in the School of Biological Sciences at Portsmouth.

The enzyme can also degrade polyethylene furandicarboxylate, or PEF, a bio-based substitute for PET plastics that is being hailed as a replacement for glass beer bottles.

PEF plastics, although bio-based, are not biodegradable, and would still end up as waste in landfills and in the seas, the NREL said in a report on its website.

“Although the improvement is modest, this unanticipated discovery suggests that there is room to further improve these enzymes, moving us closer to a recycling solution for the ever-growing mountain of discarded plastics,” said McGeehan.

The researchers, whose finding was published on Monday in the Proceedings of the National Academy of Sciences journal, are now working on improving the enzyme further to allow it to be used industrially to break down plastics in a fraction of the time, the University of Portsmouth added.

The NREL underscored the urgency of the work, pointing out that 8 million metric tons of plastic waste, including PET bottles, enter the oceans each year, creating huge man-made islands of garbage.

“Experts estimate that by 2050, there will be as much waste plastic in the ocean by mass as there are fish,” it said.

According to a three-year study published in Scientific Reports last month, a huge, swirling pile of trash in the Pacific Ocean, known as the Great Pacific Garbage Patch, is growing faster than expected and is now three times the size of France, more than double the size of Texas.

“Few could have predicted that in the space of 50 years, single-use plastics such as drink bottles would be found washed up on beaches across the globe,” said McGeehan.

“We can all play a significant part in dealing with the plastic problem,” he added. “But the scientific community who ultimately created these ‘wonder-materials’ must now use all the technology at their disposal to develop real solutions.”
An international team researching a plastic-consuming bacterium discovered in 2016 at a Japanese landfill site announce the accidental synthesis of an artificial enzyme that breaks down plastics more efficiently than the bacterium. The team suggest the molecule could be used for environmentally sound plastics disposal.