Chitosan is chemically defined as a copolymer of two residues: 2-amino-2-deoxy-d-glucopyranose (d-glucosamine) and 2acetamido-2-deoxy-d-glucopyranose (N-acetyl-d-glucosamine) , where the proportion of d-glucosamine is larger than E-mail address: reol@chem.uni.torun.plN-acetyl-d-glucosamine