APPLICATIONS AND ENVIRONMENTAL ASPECTS OF CHITIN AND CHITOSAN

A survey on the properties of the natural nitrogen-containing polysacc harides chitin and chitosan is given. Outstanding features are the mat erials' mechanical and chemical properties which offer numerous, large ly unexplored applications in technology, chemistry, medicine, and agr iculture. Derivatives of chitin and chitosan are accessible by reactio ns of the hydroxy and amino groups with appropriate reagents. Various types of gels, membranes, and fibers, including polycationic and water -soluble materials, can be formed. Production of chitin and chitosan f rom waste crab shells involves environmentally safe processes. The pol ysaccharides are recycled in nature by enzymatic degradation and reuse of N-acetylglucosamine for biosynthesis and catabolism. Research defi cits exist in economically competitive production technologies, constr uction of composite materials, and the ecological aspects of chemicall y modified chitosan.