Stop -- Don't Throw Those Crab Shells Away

Shrimp and crab shells, formerly useless waste, are a rich source of a natural polymer called chitin for which many applications are being discovered. So far, the biggest market for chitin is in water purification, particularly at food processing plants. Because it is the only biochemical substance that carries a positive charge, it can attach itself to other proteins. Protan Laboratories Inc., for example, wants to use chitin to remove solid particles from fruit juices and other beverages. Additional food processing applications are being developed. Spun into fibers, a chitin derivative makes unusually strong surgical sutures that will dissolve in the body. Japan's health authorities have approved an artificial skin made of chitin and produced by Unitika Ltd. Other applications are: 1. topical ointments that may promote healing, 2. a seed coating that improves yields of wheat, and 3. a contact lens that protects the cornea while it heals. Eight tons of dried shells will yield one ton of pure chitin to be sold at $8 per pound.