The mechanism underlying the inhibition of bacterial growth is thought to be that cationically charged amino group may combine with anionic components such as N-acetylmuramic acid, sialic acid and neuraminic acid on the cell surface, and may suppress bacterial growth by impairing the exchanges with the medium, chelating transition meal ions and inhibiting enzymes. Due to the positive charge on the C-2 of the glucosamine monomer below pH 6, chitosan is more soluble and shows better antibacterial activity