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Comment by perlgeek | Hacker News Reader

It's no surprise that microorganisms evolve quicker to adapt to environmental changes. (At least for evolutionary / genetic changes).

That makes me wonder if we'll soon see mammals with gut microbiomes that can digest microplastics.

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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.

>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 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…

On an evolutionary timescale, our plastic era probably won’t last very long, right? The byproducts might, but I guess if something learns to eat them, not so much.

Actually it seems pretty crazy that they are figuring it out so quickly (guess there’s lots of energy bound up in those molecules).

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.

Well yeah, if we insist on continuing to burn our limited supply of hydrocarbons, soon(ish) we won't have enough for making plastics either. Or plastics will become prohibitively expensive...

This is not true in a practical sense. There is a lot of petrochemicals still out there and our ability to recover marginal reserves keeps improving. I was really into the idea of peak oil when I was younger but it really hasn't panned out. Rather, if we continue to using oil, we'll cook ourselves and drown ourselves in plastic.

The eventual end goal should probably be production of hydrocarbons using solar power and CO2/water. In other words, synthetic photosynthesis.

Yep, there isn't exactly a shortage of hydrogen, carbon or energy in the world. Currently we get all three from the same place, but there are other approaches

Though sand is actually becoming a problem commodity to source now, too:

https://www.clarknexsen.com/the-global-sand-crisis-examining...

https://scitechdaily.com/the-sand-crisis-no-one-is-talking-a...

https://www.bbc.com/future/article/20191108-why-the-world-is...

That's mostly a type of sand needed for concrete, sand which is relatively "young" and has not yet had the sharp edges ground off by wind and water. You need sharp sand in construction, because "round" sand leads to weaker concrete.

Sand for glassmaking is more than abundant enough for all but the most distant futures, and even then glass is extremely recyclable.

There was an article on here (sometime in the last year?) claiming that the concrete strength issue is a myth. Apparently it's based on a very narrow claim in a single academic paper that's been wildly extrapolated.

Copper is expensive. If I were looking for a plastic alternative, I would follow the beaten path and start with aluminum.

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.

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.

It turns out there are a lot of microorganisms (and bigger) that attack your apple trees. Nothing is easy.

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.

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.

It might be a bad idea to digest plastics. If they get broken down in the gut, they'll release all those plasticisers and things into the body.

Evolution would figure that out over time with trial and error. We could instead get mammals with plastic nails/claws/hooves instead of keratin

e.g. keratin and cellulose are structural polymers not too different from materials like PET.

Can somebody do the napkin math on an estimate for how long for us to get plasticized hair and nails and teeth?

If you're interested in this topic, I'd highly recommend checking out Michigan State's E coli Long-term Evolution Experiment: https://lenski.mmg.msu.edu/ecoli/index.html

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