ABSTRACT
In the sustainable society of the future, we should rely not on limited fossil resources but on unlimited renewable resources such as biomass. Also in such a sustainable society, advanced separation technologies will become much more important for recovering valuable materials from various wastes through recycling and reuse, and for removing toxic or harmful materials from the environment. Chitosan is a basic polysaccharide containing many primary amino groups. Low-grade chitosan is a mixture consisting of about 50% chitin and 50% chitosan, which is marketed mainly as a coagulating agent for suspensions of fine solid particles. Contrary to artificial synthetic resins and solvent extraction reagents produced from petroleum, chitosan-based adsorption gels and extraction reagents are biodegradable and, therefore, environmentally benign. Chitosan is produced from the shells of crabs, shrimps, and prawns or the cartilage of squids, novel technology for producing chitosan-like polymeric materials named “bacteria chitosan” using microorganisms at low cost has been developed.
