title: Effect of sub- and supercritical water treatments on the physicochemical properties of crab shell chitin and its enzymatic degradation.
abstract: This study examined the effects of sub- and supercritical water pretreatments on the physicochemical properties of crab shell α-chitin and its enzymatic degradation to obtain N,N'-diacetylchitobiose (GlcNAc)2. Following sub- and supercritical water pretreatments, the protein in the crab shell was removed and the residue of crab shell contained α-chitin and CaCO3. Prolonged pretreatment led to α-chitin decomposition. The reaction of pure α-chitin in sub- and supercritical water pretreatments was investigated separately; we observed lower mean molecular weight and weaker hydrogen bonds compared with untreated α-chitin. (GlcNAc)2 yields from enzymatic degradation of subcritical (350 °C, 7 min) and supercritical water (400 °C, 2.5 min) pretreated crab shell were 8% and 6%, compared with 0% without any pretreatment. This study shows that sub- and supercritical water pretreatments of crab shell provide to an alternative method to the use of acid and base for decalcification and deproteinization of crab shell required for (GlcNAc)2 production.
authors.affiliation: Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567, Japan. Electronic address: osadam@shinshu-u.ac.jp.
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Osada
authors.affiliation: Department of Chemical Engineering, National Institute of Technology, Ichinoseki College, Takanashi, Hagisho, Ichinoseki, Iwate 021-8511, Japan.
authors.forename: Chika
authors.initials: C
authors.lastname: Miura
authors.affiliation: Department of Chemical Engineering, National Institute of Technology, Ichinoseki College, Takanashi, Hagisho, Ichinoseki, Iwate 021-8511, Japan.
authors.forename: Yuko S
authors.initials: YS
authors.lastname: Nakagawa
authors.affiliation: Department of Chemical Engineering, National Institute of Technology, Ichinoseki College, Takanashi, Hagisho, Ichinoseki, Iwate 021-8511, Japan.
authors.forename: Mikio
authors.initials: M
authors.lastname: Kaihara
authors.affiliation: Department of Chemical Engineering, National Institute of Technology, Ichinoseki College, Takanashi, Hagisho, Ichinoseki, Iwate 021-8511, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Nikaido
authors.affiliation: Department of Chemical Engineering, National Institute of Technology, Ichinoseki College, Takanashi, Hagisho, Ichinoseki, Iwate 021-8511, Japan.
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Totani
mesh_terms: D000118:Acetylglucosaminidase / Q000737:chemistry; D060105:Animal Shells / Q000737:chemistry*; D000818:Animals; D003386:Brachyura / Q000737:chemistry*; D002686:Chitin / Q000737:chemistry* / Q000378:metabolism*; D004798:Enzymes / Q000378:metabolism*; D014867:Water / Q000737:chemistry*
chemical_list: D004798:Enzymes; D014867:Water; D002686:Chitin; D000118:Acetylglucosaminidase
keywords: Chitin; Enzymatic degradation; Hydrothermal treatment; Marine biomass; N-Acetyl glucosamine