Crab Shells Could Become the Plastic of the Future

In this modern world, we live our daily lives in a sea of plastic, from the bottle that contains our morning face wash; to the plastic-swaddled food we grab at the store; to the water we sip in our car on the way home; all the way to the little container that holds our evening dental floss.

All this plastic is bad news for the environment—of the more than nine billion tons of plastic mankind has produced, only about 9 percent of it gets recycled, with the rest clogging our landfills and oceans—and it’s also bad for our health, messing with our hormones in ways that scientists are just beginning to understand. With both consumer and researcher interest in plastic alternatives at an all-time high, less toxic options have proliferated in our cafés and grocery stores, from edible tableware to steel and paper straws. And soon, scientists hope to add another eco-friendly choice to the field of non-plastic packaging: wrap made from crab carcasses.

Researchers at the Georgia Institute of Technology have been working on a flexible packaging material comprised of alternating layers of chitin, the primary component of crustacean shells, and cellulose, the main fiber found in green plants. The team’s efforts were described this week in the science journal ACS Sustainable Chemistry and Engineering.

According to J. Carson Meredith, one of the project’s participating researchers and a professor at Georgia Tech’s School of Chemical and Biomedical Engineering, the product the team is working on is remarkably similar in texture and appearance to the common petroleum-derived plastic used in soda bottles and potato chip bags—and it might even work better at keeping food fresh.

"The main benchmark that we compare it to is PET, or polyethylene terephthalate, one of the most common petroleum-based materials in the transparent packaging you see in vending machines and soft drink bottles," Meredith told Science Daily . “Our material showed up to a 67 percent reduction in oxygen permeability over some forms of PET, which means it could in theory keep foods fresher longer."

The team at Georgia Tech had been working with cellulose for years when it began to look into chitin—and wondered if a union of the two might just produce a perfect food packaging.

"We recognized that because the chitin nanofibers are positively charged, and the cellulose nanocrystals are negatively charged, they might work well as alternating layers in coatings because they would form a nice interface between them," Meredith said.

To make their non-plastic wrap, the researchers suspend both cellulose and chitin microfibers, respectively, in water, then spray the mixtures onto a surface in alternating layers. When the material is fully dried, it’s flexible, strong and transparent like normal plastic wrap—but is fully compostable.

And on top of being compostable, the wrap is eco-friendly in other ways. The shellfish industry already produces some six to eight million tons of chitin-rich waste each year. Every time you buy a peeled shrimp, a crab cake or a shucked oyster, the shells from those creatures have to go somewhere—and it’s usually right back in the ocean. A material utilizing those shells would help lessen the footprint of the shellfish industry.

Still, it might be some time before you’re tucking tomorrow’s sandwich into a layer of crab wrap. Even utilizing waste products, the material is much more expensive to produce than industrially manufactured plastics, and consumers likely aren’t willing to shell out (see what I did there?) the big bucks for something that ultimately gets thrown in the trash. The Georgia Tech team said they’re still looking into ways to economize the production of their tree bark-crab shell creation.

In the meantime, we’ll keep using crab shells the way we know best: still attached to the crab, fried, and stuffed into these ridiculously delicious sandwiches.