New super-enzyme eats plastic bottles six times faster

[mysteryowl]

Source: Guardian/US

A super-enzyme that degrades plastic bottles six times faster than before has been created by scientists and could be used for recycling within a year or two.

The super-enzyme, derived from bacteria that naturally evolved the ability to eat plastic, enables the full recycling of the bottles. Scientists believe combining it with enzymes that break down cotton could also allow mixed-fabric clothing to be recycled. Today, millions of tonnes of such clothing is either dumped in landfill or incinerated.

Plastic pollution has contaminated the whole planet, from the Arctic to the deepest oceans, and people are now known to consume and breathe microplastic particles. It is currently very difficult to break down plastic bottles into their chemical constituents in order to make new ones from old, meaning more new plastic is being created from oil each year.

The super-enzyme was engineered by linking two separate enzymes, both of which were found in the plastic-eating bug discovered at a Japanese waste site in 2016. The researchers revealed an engineered version of the first enzyme in 2018, which started breaking down the plastic in a few days. But the super-enzyme gets to work six times faster.

Read more: https://www.theguardian.com/environment/2020/sep/28/new-super-enzyme-eats-plastic-bottles-six-times-faster

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Love to the scientists!!

This is great news!

[cilla4progress]

1. Bookmarking!

👍

[Aussie105]

2. Recycling?

The linked article doesn't make clear what the plastic ends up as.

So what are the chemicals produced from this enzymatic digestion?

Anything of useful value?

The word 'recycling' implies a lot. Chemical breakdown by using enzymes is not the same thing.

If it is just carbon dioxide plus sludge that can't be used for anything, it's not too much progress.

[muriel_volestrangler]

6. The constituent monomers, it seems, so presumably to make new plastic

(terephthalic acid and ethylene glycol). It would have been good for the article to explain this. Here's the paper and its abstract:

Plastics pollution represents a global environmental crisis. In response, microbes are evolving the capacity to utilize synthetic polymers as carbon and energy sources. Recently, Ideonella sakaiensis was reported to secrete a two-enzyme system to deconstruct polyethylene terephthalate (PET) to its constituent monomers. Specifically, the I. sakaiensis PETase depolymerizes PET, liberating soluble products, including mono(2-hydroxyethyl) terephthalate (MHET), which is cleaved to terephthalic acid and ethylene glycol by MHETase. Here, we report a 1.6 Å resolution MHETase structure, illustrating that the MHETase core domain is similar to PETase, capped by a lid domain. Simulations of the catalytic itinerary predict that MHETase follows the canonical two-step serine hydrolase mechanism. Bioinformatics analysis suggests that MHETase evolved from ferulic acid esterases, and two homologous enzymes are shown to exhibit MHET turnover. Analysis of the two homologous enzymes and the MHETase S131G mutant demonstrates the importance of this residue for accommodation of MHET in the active site. We also demonstrate that the MHETase lid is crucial for hydrolysis of MHET and, furthermore, that MHETase does not turnover mono(2-hydroxyethyl)-furanoate or mono(2-hydroxyethyl)-isophthalate. A highly synergistic relationship between PETase and MHETase was observed for the conversion of amorphous PET film to monomers across all nonzero MHETase concentrations tested. Finally, we compare the performance of MHETase ETase chimeric proteins of varying linker lengths, which all exhibit improved PET and MHET turnover relative to the free enzymes. Together, these results offer insights into the two-enzyme PET depolymerization system and will inform future efforts in the biological deconstruction and upcycling of mixed plastics.

https://www.pnas.org/content/early/2020/09/23/2006753117

[PoindexterOglethorpe]

3. How will this be kept from getting loose

and devouring all the plastic we currently want to keep?

[muriel_volestrangler]

7. The "super-enzyme" cannot be made by bacteria themselves

so it would be under industrial control - there's no "loose" there. It could leak, I suppose, like any chemical. But it itself would be degraded in the open, since it's a protein that would be food for other bacteria.

[lonely bird]

13. The theory of paranoia applies here

Just because I am paranoid that doesn’t mean they are not out to get me.

I read an interesting novel about a fungus that had a symbiont that did precisely that. The symbiont developed the ability to breakdown plastic and the fungus used this to spread itself. Of course, the novel is fiction but nature has a way of reaching out and sack-punching humanity. Is the enzyme a bad idea? No, not in and of itself. Should care be taken when technology is used to repair technology that once was deemed a good and now is deemed a bad thing? Imo, yes. This does not mean that we should abandon this enzyme but rather that we, as a species, stop shitting in our nests.

[C Moon]

4. Gee, what could possibly go wrong?

With this new super-enzyme, we can throw our plastics anywhere.

[BootinUp]

5. There must be sci-fi movie that covers this, nt

[Aussie105]

8. Plenty movies!

No Blade of Grass (1970)
The Death of Grass (Book, 1956)

[Hekate]

9. KnR!

[JustABozoOnThisBus]

10. What else does it eat? Should we be afraid?

Bacteria that "naturally evolved the ability to eat plastic". Sure.

I hope it's contained in a secure lab. This could be worse than the plague. Worse than covid. Worse then kudzu.

[DFW]

11. Well it's about time they found a practical use for that enzyme

Originally found in the brains of Republican politicians, its capacity to quickly break down anything into mush and hot air was formerly considered to have no practical use in the commercial world.

[bucolic_frolic]

12. Money will halt this process in its tracks

It would need significant seed capital. And inducements to use recycled materials. And a knee-capping of the existing crude-to-plastics industries, all of whom will complain of financial hardship, and turn to production of other materials. I doubt you'll get less plastic out of this. You'll get significantly more.

I remember in the early 1990s they were going to build houses from plastic lumber. Structural lumber. I think GE built a prototype house in New England. Never heard another word of it. Of course when the last forest is harvested they will be seeking new materials. That should juice plastic production.

[Bayard]

14. Yay for the scientists working to save the planet!

If they can keep it on a leash.




I want to know who's throwing all their clothes away.