High Tensile Strength Regenerated α-1,3-Glucan Fiber and Crystal Transition

Abstract

α-1,3-Glucan is a linear and crystalline polysaccharide which is synthesized by in vitro enzymatic polymerization from sucrose. A previous study reported that regenerated fibers of α-1,3glucan were prepared using a wet-spinning method. However, the mechanical properties were poorer than cellulose regenerated fibers. Then, in this study, the mechanical properties of the regenerated α-1,3-glucan fiber were improved by the transformation of the crystal structure and stretching. The regenerated fiber stretched in water and dehydrated by heating showed high tensile strength (18 cN/tex) that is comparable with that of viscose rayon. Moreover, the crystal structures of the regenerated fibers were investigated using wide-angle X-ray diffraction (WAXD). To date, four crystal polymorphs of α-1,3glucan from polymorph I to IV have been reported. This study revealed that the regenerated α-1,3-glucan fibers had two different polymorphs, polymorph II (hydrated form) and polymorph III (anhydrous form), depending on post-treatment methods of stretching and annealing procedures. Furthermore, the obtained distinctive 2D-WAXD patterns suggested that polymorph III is identical to polymorph IV.

In Situ Raman Analysis of Biofilm Exopolysaccharides Formed in Streptococcus mutans and Streptococcus sanguinis Commensal Cultures

“…A library of reference Raman spectra was built up, which contained more than 40 elementary compounds and including polysaccharides (chitin, β-1,3-glucans, β-1,6-glucans, α–1, 3–glucans, α–1, 6–glucans), mono- and disaccharides (trehalose, β-D-glucose, D-dextrose), anionic lipids (phosphatidylglycerol, phosphatidylethanolamine, cardiolipin), and other key metabolites such as adenine and other nucleic acids. The reference α-1,3-glucan samples were provided by Tokyo University [ 104 ]. The library was compiled with high spectrally resolved Raman spectra collected with a triple-monochromator device (T-64000; Jobin-Ivon/Horiba Group, Kyoto, Japan) equipped with a nitrogen-cooled charge-coupled device detector (CCD-3500V, Jobin-Ivon/Horiba Group, Kyoto, Japan).…”

Bottom‐Up Synthesized Glucan Materials: Opportunities from Applied Biocatalysis

“…The as-produced fibers had tensile strength of 138 MPa, Young's modulus of 3.5 GPa, and elongation at break of 12%, which could be enhanced further through subsequent stretching and heating treatments. [128,129] 4) C-6 modified 𝜶-1,3-glucan. C-6 site-specific modification of 𝛼-1,3-glucan was conducted to develop materials.…”

“…The as‐produced fibers had tensile strength of 138 MPa, Young's modulus of 3.5 GPa, and elongation at break of 12%, which could be enhanced further through subsequent stretching and heating treatments. [ 128,129 ]…”