ABSTRACT
Chitin exists widely in nature, such as in the shell of crab, shrimp, and insects. Chitosan is an N-deacetylated product of chitin. Studies on chitin and chitosan have been enhanced since 1990 because these polysaccharides show excellent biological properties, such as biodegradation in the human body (Sashiwa et al. 1990, Shigemasa et al. 1994), immunological (Nishimura et al. 1984, Mori et al. 1987) and antibacterial properties (Tanigawa et al. 1992, Tokura et al. 1997), and woundhealing activities (Okamoto et al. 1993, Khnor and Lim 2003, Kweon et al. 2003). In recent studies it has been identied that chitosan is a good candidate to be used as a supporting material for gene delivery (Sato et al. 2001), cell culture (Mao et al. 2003) and tissue engineering (Gingras et al. 2003, Wang et al. 2003). Hence, chitin and chitosan are currently in focus and are expected to be used as new functional materials. Nevertheless, commercial or practical use of them is limited at the current stage, so therefore they are still nonutilizing biomass.
