The Next All-Natural Recycling Solution? An Enzyme

IRA FLATOW: This is Science Friday. I’m Ira Flatow coming to you today from Cincinnati Public Radio. Later in the hour, Dr. Lucy Jones is here to talk about her book The Big Ones, including California’s biggest natural disaster. It was a flood, not an earthquake, and what studying past disasters can tell us about the next big calamity.

But first, humans have made the world a pretty tough place for our fellow species to live. We’re raising global temperatures, destroying natural habitats with development, and littering the oceans with junk, especially plastic junk. But one adaptive little bacteria that says that’s OK, because it produces an enzyme that lets break down plastic bottles for energy. And scientists studying this enzyme report that they have been able to make it work even better. Here with the details, as well as other short subjects in science is Sophie Bushwick, senior editor for Popular Science. Hi, Sophie.

SOPHIE BUSHWICK: Hi, Ira.

IRA FLATOW: Let’s talk about, well, why were scientists looking at this plastic eating enzyme?

SOPHIE BUSHWICK: Well, so this enzyme eats a specific kind of plastic called polyethylene terephthalate or PET. And what’s great about that is that this is the main plastic in soda bottles. We’re produce– people buy about a million soda bottles every minute, and so they’re a major source of plastic waste. And the fact that this enzyme can break them down means that it might be a way to recycle it. So instead of having to constantly make new bottles, people could use the leftover bottles, break them down, and then make new ones out of that material.

IRA FLATOW: Well, would they– is the idea to have the bacteria, to employ the bacteria or just use the enzyme that the bacteria use?

SOPHIE BUSHWICK: The idea is to use the enzyme that the bacteria use. So researchers were studying that enzyme. It’s called PET ace. And they actually– they tweaked the structure to compare it to a different molecule, and they ended up making it even more efficient. So the new updated version of PET ace can break down plastic in a few days. Under normal circumstances, it would take 450 years to do the same thing in the– out in nature.

IRA FLATOW: Wow, can’t wait to see how this works out.

SOPHIE BUSHWICK: Me too.

IRA FLATOW: It sounds exciting. Next, researchers have identified antibiotic resistant bacteria in New York City mice. I normally would say to you why is this bad news, but it’s, sort of, itself– it answers the question itself, doesn’t it?

SOPHIE BUSHWICK: Yes, definitely. Researchers looked in four of the Boroughs of New York. They were looking in, I think, eight different buildings. They found 400 mice, and then they tested their droppings. And in the droppings they found actually some new viruses, and in addition to that, they found antibiotic resistant versions of certain bacteria like e. coli.

IRA FLATOW: And where would the mice be getting this from?

SOPHIE BUSHWICK: Well, the mice could be getting it from humans if they’re consuming, sort of, thrown out antibiotics or contaminated food. But the really worrisome thing is this just shows the sheer spread of antibiotic resistance. There’s really nowhere it seems where there’s not some antibiotic bacteria lurking.

IRA FLATOW: Are they very fearful that the mice might spread it back to people.

SOPHIE BUSHWICK: I think that’s definitely a potential issue. But I think that’s not the main concern that the researchers had. It seems that they were more worried about this indicates just how far antibiotic resistance has spread, and they were hoping they could do more work to find out just how it got to these mice.

IRA FLATOW: So the mice were, sort of, the canaries here.

SOPHIE BUSHWICK: Exactly.

IRA FLATOW: They’re not looking for a way to curb this, but just that they found this is so prevalent everywhere.

SOPHIE BUSHWICK: Yeah, definitely. And I mean it’s also a reminder that if you have a mouse problem, you should try to tackle it and get rid of them.

IRA FLATOW: Don’t literally tackle the mice, but get rid of them.

SOPHIE BUSHWICK: No, please don’t I imagine that’d be very difficult anyway.

IRA FLATOW: Well, yeah, well, there are people out there. All right, moving on. Scientists say that they’ve uncovered tiny diamonds embedded in a meteorite that gives us information about what was happening when our solar system was being formed. Tell us about that.

SOPHIE BUSHWICK: Right. So these are diamonds so small, they’re about 100 microns wide. That’s roughly the width of a human hair. And a lot of researchers have been studying the diamonds themselves, but this latest study looked inside the diamonds. So the diamonds, sort of, preserve material in pockets within them that otherwise would have been destroyed or lost. And in particular, they found a kind of material that could only form under very high pressures. The pressures that it would require are so high, you’d only find them within a planet that’s between the size of Mercury and Mars. So now researchers think that this meteorite is what remains of a very early planet that was destroyed in the early days of the solar system.

IRA FLATOW: Wow, so there’s a missing planet in our solar system.

SOPHIE BUSHWICK: There’s probably more than one. So these days we have several rocky planets in the solar system. But back in the very– in the youth of the solar system, you might say, there were tens of, sort of, early planets, the beginnings of planets. And it was just so chaotic that a lot of these big rocks would collide, and some of them would be thrown entirely out of the solar system. Others would be destroyed. They think this particular– these remains that they found most recently were probably from a planet that was destroyed.

IRA FLATOW: Somewhere– so it has to be, sort of, in the inner solar system where the rocky planets are, not up with the gas giants and things.

SOPHIE BUSHWICK: Yeah, potentially.

IRA FLATOW: Wow, that is exciting. So do we know– do we know about the conditions of the planet the diamonds came from other than its size. Was long enough– around long enough to have an atmosphere. Was it fully formed or was just when the solar system was forming?

SOPHIE BUSHWICK: I’m not sure. I think all I’m positive about is that they know the size and the approximate mass of it and that it was around very early in the solar system.

IRA FLATOW: I see another– there’s another movie on the horizon, another planet. Finally, there’s a new species of ant that have an interesting way of defending their colony.

SOPHIE BUSHWICK: There’s 15 new species of exploding ant.

IRA FLATOW: I beg my pardon.

SOPHIE BUSHWICK: It’s just real exciting.

IRA FLATOW: Well, you said exploding ant.

SOPHIE BUSHWICK: Right, so as a defense mechanism, a certain worker class among these ants can literally– they can have their abdomen rip open and they have glands that produce this, kind of, toxic good. So by sacrificing their own lives, they can get this goo on an intruder and slow it down or kill it and then prevent it from attacking the rest of the nest.

IRA FLATOW: So that’s the job of the ant is to be the walking bomb if it has to be.

SOPHIE BUSHWICK: That’s exactly right.

IRA FLATOW: Take out it must be just a group of ants that might be attacking. I guess there are enough of these exploding ants to do the job.

SOPHIE BUSHWICK: Right. You can– they’ve actually– they have a photo in the study of a larger ant species that was attacking the nest, and it’s being set upon by three of these smaller exploding ants that are committing suicide in order to take down their larger attacker. And that’s not the only adaptation.

So in the same– in one of these species, they have another class of worker that the researchers called the door keeper. And it looks, kind of, like if the ant ran into a wall and flattened the front part of its head. And it comes by that naturally, so that if there’s something trying to get into the nest, it can use its head as a blocker, as like a door to the nest and prevent anyone from entering.

IRA FLATOW: Wow, Sophie, always pleasure to have you on bringing us this new stuff. Thank you, Sophie.

SOPHIE BUSHWICK: Thanks.

IRA FLATOW: Sophia Bushwish, senior editor at Popular Science.

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