title: Alkali-induced conversion of beta-chitin to alpha-chitin.
abstract: Crystal conversion of beta-chitin to alpha-chitin by aq. NaOH treatment was studied for a highly crystalline beta-chitin sample from diatom spine. The minimum NaOH concentration to cause swelling was between 25% and 30% w/w. The alkali-swollen material was poorly crystalline and was regenerated as alpha-chitin on washing with water. This conversion caused total collapse of the original microfibrillar morphology. These features are similar to those of 7 N-8 N HCl treatment reported earlier, but alkali treatment was free from depolymerization or deacetylation.
authors.affiliation: Department of Biomaterials Science and Laboratory of Marine Biochemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan. noishiki@sbp.fp.a.u-tokyo.ac.jp
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Noishiki
authors.forename: Hiroko
authors.initials: H
authors.lastname: Takami
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nishiyama
authors.forename: Masahisa
authors.initials: M
authors.lastname: Wada
authors.forename: Shigeru
authors.initials: S
authors.lastname: Okada
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kuga
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning; D002686:Chitin / Q000737:chemistry* / Q000648:ultrastructure; D018360:Crystallography, X-Ray; D008854:Microscopy, Electron; D012972:Sodium Hydroxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000468:Alkalies; D002686:Chitin; D012972:Sodium Hydroxide