Applications and Environmental Aspects of Chitin and Chitosan

Abstract A survey on the properties of the natural nitrogen-containing polysaccharides chitin and chitosan is given. Outstanding features are the materials' mechanical and chemical properties which offer numerous, largely unexplored applications in technology, chemistry, medicine, and agriculture. Derivatives of chitin and chitosan are accessible by reactions of the hydroxy and amino groups with appropriate reagents. Various types of gels, membranes, and fibers, including polycationic and watersoluble materials, can be formed. Production of chitin and chitosan from waste crab shells involves environmentally safe processes. The polysaccharides are recycled in nature by enzymatic degradation and reuse of N-acetylglucosamine for biosynthesis and catabolism. Research deficits exist in economically competitive production technologies, construction of composite materials, and the ecological aspects of chemically modified chitosan.