Fighting Plastic Waste With Mealworms
QUEST: A long-term priority with you to inspire to bring forward change to come up with new ideas. It's CNN's "CALL TO EARTH", our call to action on the environment, where together, we move forward. Tonight's report, how an insect can help combat plastic pollution.</s>ANJA BRANDON, SCIENTIST, STANFORD UNIVERSITY: 1,000 mealworms can eat about two grams of plastic a week. So, it would take 3,000 or 4000 mealworms to eat this Styrofoam cup about a week.</s>UNIDENTIFIED FEMALE: That's Anya Brandon, a scientist at Stanford University. She studies how these eat this and yet can still be used to feed these.</s>BRANDON: So, we all know that plastics are a huge issue facing the environment, especially in the marine environment, and we're all looking for good ways on how to deal with all these plastic wastes that we have. And we found that mealworms are these tiny innocuous insects found pretty much everywhere, can eat and degrade a few different types of plastic.</s>UNIDENTIFIED FEMALE: Mealworms are basically the larvae of the type of darkling beetle. They do have a commercial use as food for livestock like pigs and chickens. But then, it was discovered in 2015, that these little grubs could eat polystyrene. And a whole new line of research opened up, one that Brandon has pursued.</s>BRANDON: So, why these little mealworms are able to eat plastics, it's still an open question. We're still trying to research that. There's other insects out there that eat predominantly wax, which is also full of long chain polymers. And it looks like somehow, evolutionarily, these insects that are used to eating and breaking down these naturally existing big polymers are fortuitously able to break down some of these plastics that were putting into the world.</s>UNIDENTIFIED FEMALE: Brandon's first discovery was that it wasn't just polystyrene that mealworms chomped down on, they ate polyethylene, too.</s>BRANDON: That's really cool because one issue that we have with plastic waste is that it's really hard to recycle multiple types of plastics together.</s>UNIDENTIFIED FEMALE: This is how they do it. Plastic has no nutrients in it. So, it's the energy from breaking down the plastics polymer bonds that the mealworms are after. They do this using a powerful bacteria in their gut, which breaks down the majority of plastic in to nothing but hydrogen and carbon. But there are other ingredients in plastics that are not quite so easy to break down.</s>BRANDON: There's all sorts of crazy chemicals used in plastics' manufacturing, from stabilizers, to plasticizers, to flame retardants, and that's a problem because we know that some of these chemicals can be toxic.</s>UNIDENTIFIED FEMALE: When Brandon looked into this, she found that some degraded plastics did come out the other end of the mealworm and flushed out with them, came all the chemicals that could do harm further up the food chain.</s>BRANDON: So, they're not bio accumulating. That means that this mealworm is still a valuable feed source, which is great.</s>UNIDENTIFIED FEMALE: But it's not the feed industry Brandon is interested in for her research. For her, it's a question of scaling up. And to do that, she needed to understand how a mealworm does what it does.</s>BRANDON: So, we're looking and trying to isolate the bacteria from the mealworm gut, to be able to scale those up and use big fats that we call bioreactors that are just chock full of bacteria. You can throw your plastic in and hopefully, it'll all break down.</s>QUEST: Practical solutions to real-life problems. We'll continue to focus and prioritize those of you who are doing such magnificent work in this. And please, tell me your stories, and do so using the hashtag #calltoearth.