Effect of Sonolysis on Acid Degradation of Chitin to Form Oligosaccharides

Abstract

Abstract Chitin [partially deacetylated β-(1→4)-linked 2-acetamide-2-deoxy-β-d-glucopyranose, (GlcNAc)n] was hydrolyzed by hydrochloric acid under the ultrasound irradiation. The first seven members of (GlcNAc)n in the degradation fluid were analyzed with high performance liquid chromatography (HPLC). The produced amounts of (GlcNAc)1—7 obtained by the degradation in concd HCl increased almost in proportion to the degradation time up to 120 min when sonolysis was used concomitantly. The yield of saccharides in the degradation fluid by concd HCl with sonolysis was about 2—4 times as much as that in the hydrolysis without sonolysis. The yield(%) increased with increasing of the concentration of HCl (6—12 mol dm−3) but decreased with increase of the concentration of chitin, showing a solvent volume effect. For the production of higher oligosaccharides, such as (GlcNAc)5—7, degradation with sonolysis for not longer than two hours is desirable. Deacetylated products were negligible. The effect of sonolysis is discussed from the aspect of the interactions of water with saccharide chains.