- Enzymatic synthesis of cellulose II-like substance via cellulolytic enzyme-mediated transglycosylation in an aqueous medium
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The enzymatic synthesis of cellulose-like substance via a non-biosynthetic pathway has been achieved by transglycosylation in an aqueous system of the corresponding substrate, cellotriose for cellulolytic enzyme endo-acting endoglucanase I (EG I) from Hypocrea jecorina. A significant amount of water-insoluble product precipitated out from the reaction system. MALDI-TOF mass analysis showed that the resulting precipitate had a degree of polymerization (DP) of up to 16 from cellotriose. Solid-state 13C NMR spectrum of the resulting water-insoluble product revealed that all carbon resonance lines were assigned to two kinds of anhydroglucose residues in the corresponding structure of cellulose II. X-ray diffraction (XRD) measurement as well as 13C NMR analysis showed that the crystal structure corresponds to cellulose II with a high degree of crystallinity. We propose the multiple oligomers form highly crystalline cellulose II as a result of self-assembly via oligomer-oligomer interaction when they precipitate.
- Hattori, Takeshi,Ogata, Makoto,Kameshima, Yumiko,Totani, Kazuhide,Nikaido, Mitsuru,Nakamura, Takashi,Koshino, Hiroyuki,Usui, Taichi
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scheme or table
p. 22 - 26
(2012/07/02)
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- Regioselective glucosylation of inositols catalyzed by Thermoanaerobacter sp. CGTase
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Monoglucosylated products of l-chiro-, d-chiro-, muco-, and allo-inositol were synthesized by regioselective α-d-glucosylation with cyclodextrin glucosyl transferase from Thermoanaerobacter sp. after hydrolysis of by products with Aspergillus niger glucoamylase. While the reactions carried out with d-chiro-, muco-, and allo-inositol resulted in the regioselective formation of monoglucosylated products, two products were obtained in the reaction with l-chiro-inositol. Through the structural characterization of the glucosylated inositols here we demonstrated that the selectivity observed in the glucosylation of several inositols by Thermoanaerobacter sp. CGTase, is analogous to the specificity observed for the glucosylation of β-d-glucopyranose and equivalent glucosides.
- Miranda-Molina, Alfonso,Marquina-Bahena, Silvia,Alvarez, Laura,Lopez-Munguia, Agustin,Castillo, Edmundo
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p. 93 - 101,9
(2020/08/20)
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