Fully compostable bioplastic made from shrimp shells

Researchers at Harvard's Wyss Institute have developed a method to carry out large-scale manufacturing of everyday objects—from cell phones to food containers and toys—using a fully degradable bioplastic isolated from shrimp shells.

The objects exhibit many of the same properties as those created with synthetic plastics, but without the environmental threat. It also trumps most bioplastics on the market today in posing absolutely no threat to trees or competition with the food supply. The advance was reported online last week in Macromolecular Materials & Engineering.

Most bioplastics are made from cellulose, a plant-based polysaccharide material. The Wyss Institute team developed its bioplastic from chitosan, a form of chitin, which is a powerful player in the world of natural polymers and the second most abundant organic material on Earth. Chitin is a long-chain polysaccharide that is responsible for the hardy shells of shrimps and other crustaceans, armor-like insect cuticles, tough fungal cell walls—and flexible butterfly wings.

The majority of available chitin in the world comes from discarded shrimp shells, and is either thrown away or used in fertilizers, cosmetics, or dietary supplements, for example. However, material engineers have not been able to fabricate complex three-dimensional (3D) shapes using chitin-based materials—until now.

The Wyss Institute team, led by Postdoctoral Fellow Javier Fernandez, Ph.D., and Founding Director Don Ingber, M.D., Ph.D., developed a new way to process the material so that it can be used to fabricate large, 3D objects with complex shapes using traditional casting or injection molding manufacturing techniques. What's more, their chitosan bioplastic breaks down when returned to the environment within about two weeks, and it releases rich nutrients that efficiently support plant growth.