February 12 2011

growing plastic… from mushrooms?

I love mushrooms. Stuffed criminis, grilled portobellos, stir-fried shitakes, or even plain white mushrooms tossed in a salad. However you eat them, mushrooms are delicious. Eben Bayer from Ecovative Design also loves mushrooms. But he’s not interested in eating them - instead, he’s using them to grow plastic!

As Bayer shows in his talk, mycelium (basically mushroom roots) can be grown in molds to create completely compostable packaging products. As the mycelium grows, it creates long branching networks of filamentous cells. These cells are surrounded by strong cell walls that contain a compound called chitin. In nature, chitin is not only found in mushrooms, but also in the cell walls of other fungi such as yeast, as well as the exoskeletons of insects and crustaceans.

Like its more traditional packaging counterpart styrofoam, chitin is a polymer. Polymers are simply defined as long strings of of smaller subunits called monomers. We’ve already talked about two types of polymers here before: proteins and Teflon, which are made up of amino acids and the small chemical compound tetrafluorethylene, respectively. In the case of styrofoam, molecules of styrene are attached to one another to form long polystyrene chains.

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Chitin, on the other hand, is made up of the sugar N-acetylglucosamine.

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Chitin can form very tough, leathery networks which makes it useful for manufacturing growing eco-friendly packaging products. Yet Eben Bayer and his friends at Ecovative Design are by no means the first people to put chitin to good use. Chitin is already being used in everything from water filtration systems and medical sutures to nail polish and anti-bacterial sponges. With all of chitin’s durability and versatility, who knows what it will be used for next!

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Biologist by day, culinary enthusiast by night. What better way to combine my interests in science and cooking than to write about them here?

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