I think this does mean that plastic things could soon rot. It could be pretty interesting based on how it spreads. Call a remediation company because you noticed the plastic-mold growing in your house somewhere.
Time to invent a type of plastic that's poisonous to these bacteria!
> Is it harmful to humans?
> Not at all! You can definitely trust that my company has studied this in depth. I'm sure it isn't going to make it into everyone's bloodstreams before we learn it's actually terrible.
The paper frames this as microorganisms "exploring novel ecological niches." More accurate framing: we accidentally created a massive evolutionary pressure toward undoing one of our primary material technologies. And we can't stop it. Oops?
Polyethylene terephthalate is a little unique. Part of its popularity comes from recycling, because it is "easy" to break down. For other polymers like polystyrene or PVC it's not so easy.
But any plastic is going to be harder to break down than cellulose because life depends on water and plastics are usually hydrophobic. So non-porous things will always break down pretty slowly. Plenty of plants grow in the water, after all, and aren't immediately consumed by bacteria. Microplastics should, in principle, be the first things to go.
Robes are probably a big one as well - in the olden days (before plastics) any ropes you used in the sea would rot fairly quickly. Nowadays that obviously isn't a problem - we have really good fairly cheap robes made of plastic, but maybe in the future it will become a problem again
I love this story and have repeated it to many people because of how wonderfully it sparks the imagination. Unfortunately, this theory simply doesn't hold up to modern evidence. It turns out we've had white rot fungi as long as we've had lignin
Wood has always been decomposable by fungi. The idea that there was a lag in evolution is a once-prominant myth that has since been disproven.
Plastics are not a single chemical. If anything it's more of a characteristic of a wide variety of polymers which are typically synthetically derived from petroleum are extremely varied. Even if fungi/bacteria eventually evolve the correct enzymes to break down some of the plastics, it's foolish to think all plastics will be solved by evolution. Especially since many of these enzymes result in other microplastic compounds instead of full decomposition.
It's also a little rash to hope for it given how much of the world's infrastructure would be threatened by such a development.
Makes me wonder if we're building towards another extinction/oxygen catastrophe type of event. Not one where the microplastics themselves are the primary driver, but because microplastics are not renewable in the environment without humans. With solar energy transitions, greater pollution awareness, and a population that's shrinking or leveling off, what will happen to all of the microorganisms which spent a great deal of energy evolving ways to metabolize plastics that suddenly lose that source of energy? They're suddenly less fit for their niche.
Or in a different area of concern, what happens to the plastic economy when plastics are no longer useful because they'll be decomposed too quickly? Sanitary packaging for medical supplies come to mind.
That seems very far away. My understanding is that these PETases digest plastic VERY slowly and need human engineering efforts to digest it in any appreciable amount of time (hours to days rather than years). And human bioengineering of these enzymes is still not to the point where it's actually usable at industrial scale. The paper just says they've discovered the variants, not "oh no all animal life on earth is now dependent on microplastics" :D
> What happens to the plastic economy when plastics are no longer useful because they'll be decomposed too quickly?
We already use lots of biodegradable things for crucial applications, such as the wood used in framing houses. Just because wood can rot in a damp forest doesn't mean that the wood inside your walls will rot away just because. There are conditions where it can start rotting, and we're aware of those conditions and how to prevent them, at least enough for a house to last for decades.
Just because they can digest PET does not mean they cannot digest other things. Being able to switch between food sources as they become more or less abundant is a very common adaptation.
The lifespan of microorganisms is sufficiently short (in most cases) that you’re turning over the entire population regularly - the reason you see such rapid evolution in microorganisms is because they do an enormous amount of dying and procreating anyway. As such, it’s hard to really quantify what a microorganism extinction event would look like in a way that meaningfully distinguishes it from any random Tuesday.
>what will happen to all of the microorganisms which spent a great deal of energy evolving ways to metabolize plastics that suddenly lose that source of energy?
As the article implies, microorganisms evolve relatively quickly. So the answer is, they would evolve to consume another source of energy. (As has happened for the subjects of the article in the opposite direction.)
I don't think they are unlearning how to eat other things. It's humans who will have to find a new way to build cars, planes, boxes, bottles and electronics. Think how expensive it will be once car tire or fiber-optic cable eating bacteria hits a major city. Your access to fresh food will be limited and you don't even have a single apple tree.
I think environmental conservation efforts would have to be fairly successful for your concern.
Fortunately, the US will see that possibility isn't very likely. In the 1980s, there was growing concern about the use of plastic and styrofoam one-time packaging. Both still widely used today…
I guess we’ll have to go back to our old friends glass and copper. Petrochemicals were a fad anyway; glass and copper have been with us the whole time.
Yeah, I really look forward to seeing more research on the ability of these PETase genes to spread. The article touched on it briefly, but it’d be great to have more insight on how much of this is due to HGT vs. something likely to originate de novo across species.
> That makes me wonder if we'll soon see mammals with gut microbiomes that can digest microplastics.
On a less serious note, my cat is deadset on this accomplishment.
I'm guessing evolution of these is driven more by microfibers from polyester cloth (which is also PET) rather than plastic bottles. The fibers have much higher surface area for bacteria to attack.
This is fascinating! Is this on-net good or bad for humans? On one hand, bacteria that consume plastics can help clean up the mess humans have produced, keeping the world somewhat more balanced. On the other, plastics are very useful to humans, so if they start "rotting" away this could cause lots of problems for society.
My guess is that this is on-net good for humanity. Curious what more qualified folks think.
Plastic is a hydrocarbon. If bacteria can metabolize it, we have a whole new source of GHG on our hands. It looks like 5–10% of petroleum ends up as plastic, which seems like a decently sized new supply of GHG to worry about. Even if we switched entirely to renewables tomorrow, we'd still have 5–10% of all of our emissions ever just sitting there waiting to eventually be released by bacteria. (Over what time span, I have no idea.)
Plastic was easy mode. Whatever we come up with to replace it is going to make things shittier somehow. In the form of more expensive processing and probably more exotically produced (harmful to humans working the plant).
I wonder if we really will come up with a replacement at all. Even if the bacteria can digest plastics, I can imagine that it may take N years to fully degrade a 0.125" piece. If N is 10 years, then maybe we just accept that plastics become unusable after 10 years for most applications -- For most of the things I use, I think this would be fine. Plumbing would be a disaster though. But if N is 1 year then ya, I think we'll need something totally new.
Plastics as in "polymers made of small organic monomers" are sort of a universal solution. Nature uses them a lot as well. For the same reasons we do, too.
Probably not. All these critters definitely eat other stuff as well. And their non-plastic-eating cousins are probably still around anyway, and would just resume their former role if the plastic eaters died off.
A lot of cities are in the process of replacing lead pipes with plastic. Replacing them again is going to be a huge burden, especially with an increasingly aging population and fewer people to do manual labor unless we have some sort of good automation for manual labor.
Readit News
This could be bad too I suppose? Pipes and other chemical containment vessels might come under attack.
"Dammit the TV's rotting!"
Wish I could remember the name of it, as I roughly remember the book as being pretty good too. :)
In the presence of moisture, maybe. The are plenty of microorganisms that can break down wood and paper, yet they can still stay intact for centuries.
> Is it harmful to humans?
> Not at all! You can definitely trust that my company has studied this in depth. I'm sure it isn't going to make it into everyone's bloodstreams before we learn it's actually terrible.
But any plastic is going to be harder to break down than cellulose because life depends on water and plastics are usually hydrophobic. So non-porous things will always break down pretty slowly. Plenty of plants grow in the water, after all, and aren't immediately consumed by bacteria. Microplastics should, in principle, be the first things to go.
https://medium.com/@datavector/why-plastic-eating-bacteria-e...
Curiously near Chernobyl, decomposition microbes are suppressed, so things can hang around longer: https://www.smithsonianmag.com/science-nature/forests-around...
I love this story and have repeated it to many people because of how wonderfully it sparks the imagination. Unfortunately, this theory simply doesn't hold up to modern evidence. It turns out we've had white rot fungi as long as we've had lignin
https://www.pnas.org/doi/10.1073/pnas.1517943113
Plastics are not a single chemical. If anything it's more of a characteristic of a wide variety of polymers which are typically synthetically derived from petroleum are extremely varied. Even if fungi/bacteria eventually evolve the correct enzymes to break down some of the plastics, it's foolish to think all plastics will be solved by evolution. Especially since many of these enzymes result in other microplastic compounds instead of full decomposition.
It's also a little rash to hope for it given how much of the world's infrastructure would be threatened by such a development.
That makes me wonder if we'll soon see mammals with gut microbiomes that can digest microplastics.
Or in a different area of concern, what happens to the plastic economy when plastics are no longer useful because they'll be decomposed too quickly? Sanitary packaging for medical supplies come to mind.
> What happens to the plastic economy when plastics are no longer useful because they'll be decomposed too quickly?
We already use lots of biodegradable things for crucial applications, such as the wood used in framing houses. Just because wood can rot in a damp forest doesn't mean that the wood inside your walls will rot away just because. There are conditions where it can start rotting, and we're aware of those conditions and how to prevent them, at least enough for a house to last for decades.
As the article implies, microorganisms evolve relatively quickly. So the answer is, they would evolve to consume another source of energy. (As has happened for the subjects of the article in the opposite direction.)
Fortunately, the US will see that possibility isn't very likely. In the 1980s, there was growing concern about the use of plastic and styrofoam one-time packaging. Both still widely used today…
> That makes me wonder if we'll soon see mammals with gut microbiomes that can digest microplastics.
On a less serious note, my cat is deadset on this accomplishment.
My guess is that this is on-net good for humanity. Curious what more qualified folks think.