Styrofoam, it’s what’s for dinner

Styrofoam cups are one of the most useful inventions of the modern world. However, this material poses an enormous problem to the environment. Every year, Americans throw away about 2.5 billion foam cups, and while styrofoam is recyclable, most people just toss their styrofoam waste in with the regular trash anyway. To make matters worse, styrofoam is an inert substance (it doesn’t react with anything), and therefore takes hundreds of years to decompose. That means our piles of styrofoam trash are not going to disappear anytime soon.

The good news is that scientists at the Beihang and Stanford Universities may have just found a solution to our problem, and it involves tiny worms. In their recent publication, Yang et. al found that over the course of a month, mealworms were able to live off a diet consisting solely of styrofoam, and remain as healthy as mealworms fed a normal diet (bran). Moreover, the researchers demonstrated that the mealworms were able to convert nearly half of the styrofoam into carbon dioxide and mealworm poop within 16 days.

So how exactly do mealworms do this?

The truth is that mealworms themselves aren’t responsible for breaking down styrofoam, rather it’s the bacteria in their gut that do this. In fact, these scientists were able to isolate the styrofoam-eating bacteria and identify it as Exiguobacterium sp. strain Y2. Interestingly, when these bacteria were grown outside the mealworm’s gut on Petri dishes lined with styrofoam, they actually took longer to break down the styrofoam. The most likely explanation is that there are other bacteria in the gut that grow alongside Exiguobacterium sp. strain Y2 and provide additional nutrients the bacteria needs besides styrofoam. Scientists call this type of mutually beneficial partnership “symbiosis”.

Now, you might be wondering whether there are bacteria that can munch on other types of inert waste products too? The answer to that is yes! In 2014, the same researchers also found that wax worms were able to eat through a polyethylene film (the most commonly used plastic), and again isolated the bacterial species responsible for it.

So while bacteria may be very small, they can have an extraordinarily large impact on our world. Not only do we rely on them for making many of our food products, we may soon be relying on them to decompose the very containers we package them into as well!

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