Making a mealworm of it
What to do with all those disposable coffee cups that can’t be recycled and other plastics that don’t break down in the environment? The answer could lie in plastic-eating worms and bacteria.
Engineers at Stanford University, in collaboration with Chinese researchers, have shown that the common mealworm can survive and thrive on a diet of Styrofoam and other types of polystyrene and degrade this in its gut. The mealworms in the experiment, as they do with all food, converted about half the plastic to carbon dioxide and excreted most of the remainder within 24 hours as biodegraded fragments that looked similar to rabbit droppings. The researchers say this waste seems safe to use to help grow food crops.
The researchers hope the mighty mealworm can become even more so through genetic engineering to make them digest faster – and that larger animals may have a similar gut makeup, allowing research to move up the food chain. As an article on Salon said, “Imagine the king of the jungle safely feasting on hyenas, zebras and your smart TV packaging.”
Meanwhile, Japanese researchers have discovered bacteria that can break down one of the most used plastics, polyethylene terephthalate, commonly called PET or polyester. The bacteria took much longer to chomp through the highly crystallised PET used in plastic bottles, but they were much more voracious than a related bacterium, leaf compost and a fungus enzyme that were also recently found to be able to consume PET.
PET has particularly strong bonds, and until recently, the researchers say, no organisms were known to be able to decompose it. But this may be a case of evolution to the rescue, a response to all the plastic accumulating in the environment over the past 70 years.
Swinburn University professor Uwe Bornscheuer told the Guardian that microbes have an extraordinary ability to adapt to their surroundings. “If you put bacteria in a situation where they’ve got only one food source to consume, over time they will adapt to do that.”