Scientists accidentally engineer enzyme to eat plastic waste


#1

Originally published at: https://boingboing.net/2018/04/17/scientists-accidentally-engine.html


#2

Sweet.

Now, how many types of plastic are out there…?


#3

What does it turn the plastic into?


#4

Don’t worry, they’ll eventually engineer an enzyme to take care of that…


#5

But which enyzyme will then take care of the enzyme which takes care of the first enzyme?


#6

As long as this doesn’t turn out like Greg Bear’s “Blood Music” we’ll be fine.
*fingers crossed


#7

Actually, that sounds pretty good; sign me up.


#8

I’ve read more than one sci-fi story about a post-plastic apocalypse caused by engineered micro-organisms that got released and ate all the plastic. Think about it. We don’t own many things that aren’t at least partly plastic. Cases, insulation, knobs… hospitals will be wiped out of medical gear… clothes will rot on the rack and right off our backs…


#9

There are a ton of different plastics, but the most common ones are PET (ie. polyester), high- and low-density PE (polyethylene), PVC, polypropylene (PP), and polystyrene (PS).

An enzyme that allows bacteria to eat PET would be tremendously useful, but not solve plastic pollution on its own.


#10

Is anyone sure there’s absolutely no way this is going to go all Doomwatch on us?


#11

Nice pop-culture reference there! I wonder how many people would know what Doomwatch was? I remember one episode about super-rats, where a horse had been eaten alive in its stable, pretty shocking to see on telly back then.
I can’t help but think there’s a place in the scheduling for an updated version right now.


#12

Just to play Devil’s advocate here…

All those stories, or the ones like the extraterrestrial virus in Andromeda Strain that eats rubber, all suppose the microbes not only are airborne (which a very small fraction of microbes actually are), but capable of surviving in a wide range of environments. Certainly you could deliberately engineer those traits into microbes, but what are the odds of accidentally happening on the bacterial equivalent of Superman? I’d guess much less than the odds of accidentally engineering in a single superpower (or in this case enzyme).

Now to pivot and play God’s advocate…

This does concern me. Thermal depolymerization and photodegredation of petroleum-based plastics such as PET can release the chemical bisphenol A polycarbonate used in their production (please see @wsmcneil’s reply to me below for correction), and this chemical is mildly toxic. You know it as BPA from warning labels on your hard plastic consumer goods. However…

Enzymologists have had enzymes to break down BPA for a while now. They’re in the oxidoreductase chemical family. A fungus called Cunninghamella elegans has been shown to produce one called cytochrome P450 oxidoreductase (CPR) which can break down BPAs. A bacterial called Pseudomonas fluorescens uses an oxidoreductase enzyme called 4-hydroxyacetophenone monooxygenase to break BPA down into water, 4-hydroxyphenyl acetate (found in foods such as beer and olive oil), and finally nicotinamide adenine dinucleotide phosphate, AKA NADP+ (a chemical used by all life on earth to sytnehsize essential cell structures).

[TL;DR ~ if the only toxic byproduct of this new process is BPA, there’s already enzymes for degrading that into safe chemicals.]

Frustratingly, the article doesn’t deign to provide us with what the products are. All the un-credited author bothers to tell us is a quote from the project leader that, “The engineering process is much the same as for enzymes currently being used in bio-washing detergents and in the manufacture of biofuels…” This suggests they’re probably referring to methanolysis (the opposite of bulk ring-opening transesterification used to make numerous polymers).

Remember, a polymer is just a long-chain repeating organic chemical, whether it be plastic or RNA), first synthesized in 1907 by chemist Leo Baekeland (though mass production was achieved by Wallace Carothers’ accidental invention of nylon at DuPont labs in 1935 two years before his tragic death). However it’s accomplished, destroying a polymer involves chemicals or physical processes that mechanically take it apart.

SF trivia time: In the Known Space universe there’s a scene in Flatlander by Larry Niven where the nearly indestructible General Products hulls are revealed to be an advanced form of single long-chain of polymerized diamond when ambient anitmatter breaks the bonds and the whole thing unravels, appearing to evaporate around the crew. This was written 24 years before the discovery of carbon nanotubes!


It should also be noted that the CNN article is a little confusing. According to the second article, the microorganism that produces the enzyme was already capable of breaking down plastic…

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.

The goal was to determine its structure, but they ended up going a step further and accidentally engineered an enzyme which was even better at breaking down PET…

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


#13

Do you want Thread, because that’s how you get Thread.


Comment made entirely in jest. I am not suggesting it is even possible that this will turn us into Pern.


#14

I’ve read this one. It doesn’t go well for us.
https://goo.gl/images/CmUqY3


#15

Plastics are organic molecules, no? So we’ve invented something that eats organic molecules. This isn’t going to end well.


#16

Later as a stand-alone book.

ETA: Didn’t see @dreamrnj image.


#17

Well, enzymes aren’t self-replicating so I doubt there’s much of an issue there, but I agree that this looks half-baked at best right now. That’s a pretty complex molecule and the various forms of degradation can leave some pretty toxic shit behind.


#18

Airborne cancer. But we won’t have to worry about that for years.


#19

Ooh i’m reading this book as we speak.

No spoilers! :neutral_face:


#20

Never! Enjoy it. “Slant” is pretty good Bear too.