Chitin is the second most abundant polysaccharide found on
earth next to cellulose. Chitin is the main component in the shells
of crustaceans, such as shrimp, crab and lobster. Chitin is a polysaccharide
very similar in structure to cellulose being composed of
poly-2-acetamido-2-deoxy-D-glucose (Pigman & Horton, 1965).