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Scientists accidentally create mutant enzyme that eats plastic bottles

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Scientists accidentally create mutant enzyme that eats plastic bottles

Article:
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."


Of course there is still testing to do to make sure that this doesn't cause more harm than good to the environment in the long run (one possible downside is carbon emissions). Until then however, I daresay I feel cautiously optimistic about this whole shibang.


Sidenote: does anybody have acess to the journal the actual research is published in? I'd love to see it.
 
I suppose the most important part: "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."

Exactly what are the original components?


PS: I do have the paper, but like hell I can make sense of it myself :V
 
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Sumeragi said:
I suppose the most important part: "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."

Exactly what are the original components?
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How plastics are made

There's a list, but most key: "Other raw material chemicals are isolated from petroleum, such as benzene and xylenes. These chemicals are reacted with others to form the monomers for polystyrene, nylons, and polyesters. The raw materials have been changed into monomers and no longer contain the petroleum fractions. "

So basically if they can get benzene and xylenes back out that'd be nice.
 
Sumeragi said:
I suppose the most important part: "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."

Exactly what are the original components?
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Depends on the plastic in question. Like steel, the exact compostiion varies hugely.
 
Eliar said:
So can we unleash this thing to start eating the crap in the oceans and rivers or?
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Releasing an organism that can live in the wild and efficiently eats plastic risks it eating plastic we don't want eaten.

Worst case would be a "Ringworld Superconductor Plague" scenario where all plastic goes away and technological civilization falls apart since it's used so many places. In a more moderate scenario, it becomes common for plastic to rot and it constantly has to be replaced.
 
Avernus said:
Releasing an organism that can live in the wild and efficiently eats plastic risks it eating plastic we don't want eaten.

Worst case would be a "Ringworld Superconductor Plague" scenario where all plastic goes away and technological civilization falls apart since it's used so many places. In a more moderate scenario, it becomes common for plastic to rot and it constantly has to be replaced.
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As far as I'm aware, this is just a loose enzyme, rather than a full-fledged microbe. It shouldn't reproduce under its own power.
 
One neat point is what the improvement they did implies-

"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."
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While good news, the paranoid part of my brain imagines this escaping the lab. All of sudden, plastic every starts breaking down. Pipes, car parts, appliance parts, plastic cups, containers etc... It could be Armageddon here folks.
 
I just write said:
As far as I'm aware, this is just a loose enzyme, rather than a full-fledged microbe. It shouldn't reproduce under its own power.
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My point was that if you wanted to use it to do something like clean up the oceans, given the sheer scale of the problem you'd basically have to genetically engineer it into something that can reproduce.
 
Lazer Raptor said:
Scientists accidentally create mutant enzyme that eats plastic bottles

Article:
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."


Of course there is still testing to do to make sure that this doesn't cause more harm than good to the environment in the long run (one possible downside is carbon emissions). Until then however, I daresay I feel cautiously optimistic about this whole shibang.


Sidenote: does anybody have acess to the journal the actual research is published in? I'd love to see it.
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It's this paper, I believe:
Article:
Characterization and engineering of a plastic-degrading aromatic polyesterase

Harry P. Austin, Mark D. Allen, Bryon S. Donohoe, Nicholas A. Rorrer, Fiona L. Kearns, Rodrigo L. Silveira, Benjamin C. Pollard, Graham Dominick, Ramona Duman, Kamel El Omari, Vitaliy Mykhaylyk, Armin Wagner, William E. Michener, Antonella Amore, Munir S. Skaf, Michael F. Crowley, Alan W. Thorne, Christopher W. Johnson, H. Lee Woodcock, John E. McGeehan and Gregg T. Beckham

PNAS April 17, 2018. 201718804; published ahead of print April 17, 2018. Characterization and engineering of a plastic-degrading aromatic polyesterase

Edited by Alexis T. Bell, University of California, Berkeley, CA, and approved March 28, 2018 (received for review October 29, 2017)

Significance

Synthetic polymers are ubiquitous in the modern world but pose a global environmental problem. While plastics such as poly(ethylene terephthalate) (PET) are highly versatile, their resistance to natural degradation presents a serious, growing risk to fauna and flora, particularly in marine environments. Here, we have characterized the 3D structure of a newly discovered enzyme that can digest highly crystalline PET, the primary material used in the manufacture of single-use plastic beverage bottles, in some clothing, and in carpets. We engineer this enzyme for improved PET degradation capacity and further demonstrate that it can also degrade an important PET replacement, polyethylene-2,5-furandicarboxylate, providing new opportunities for biobased plastics recycling.
​
Abstract

Poly(ethylene terephthalate) (PET) is one of the most abundantly produced synthetic polymers and is accumulating in the environment at a staggering rate as discarded packaging and textiles. The properties that make PET so useful also endow it with an alarming resistance to biodegradation, likely lasting centuries in the environment. Our collective reliance on PET and other plastics means that this buildup will continue unless solutions are found. Recently, a newly discovered bacterium, Ideonella sakaiensis 201-F6, was shown to exhibit the rare ability to grow on PET as a major carbon and energy source. Central to its PET biodegradation capability is a secreted PETase (PET-digesting enzyme). Here, we present a 0.92 Å resolution X-ray crystal structure of PETase, which reveals features common to both cutinases and lipases. PETase retains the ancestral α/β-hydrolase fold but exhibits a more open active-site cleft than homologous cutinases. By narrowing the binding cleft via mutation of two active-site residues to conserved amino acids in cutinases, we surprisingly observe improved PET degradation, suggesting that PETase is not fully optimized for crystalline PET degradation, despite presumably evolving in a PET-rich environment. Additionally, we show that PETase degrades another semiaromatic polyester, polyethylene-2,5-furandicarboxylate (PEF), which is an emerging, bioderived PET replacement with improved barrier properties. In contrast, PETase does not degrade aliphatic polyesters, suggesting that it is generally an aromatic polyesterase. These findings suggest that additional protein engineering to increase PETase performance is realistic and highlight the need for further developments of structure/activity relationships for biodegradation of synthetic polyesters.
​
[continue reading]

The article is open access, so you're free to read it all.
 
Wasn't this an episode of Godzilla the Series? It may not be made of nanobots but let's hope it doesn't turn into a plastic eating Kaiju :p
 
Avernus said:
My point was that if you wanted to use it to do something like clean up the oceans, given the sheer scale of the problem you'd basically have to genetically engineer it into something that can reproduce.
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If you are making the enzyme, that basically means its the government doing it, because I can't see it as profitable for businesses, and it also means that you are spending resources and generating pollution making the enzyme you intend to use to fight pollution which is kind of 2 steps forward 1 step back.
 
firefossil said:
If you are making the enzyme, that basically means its the government doing it, because I can't see it as profitable for businesses, and it also means that you are spending resources and generating pollution making the enzyme you intend to use to fight pollution which is kind of 2 steps forward 1 step back.
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Depends on how energy intensive the process is, what the byproducts are, what power plants are being used to fuel it, what's being done with the byproducts, and a million other things. It isn't just "thing is being done, by government, ergo pollution is made worse".
 
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