Solid-state spectroscopic analysis of lignins from several Austral hardwoods

✍ Scribed by A.T Martı́nez; G Almendros; F.J González-Vila; R Fründ

• Book ID: 104358045
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 177 KB
• Volume: 15
• Category: Article
• ISSN: 0926-2040
• DOI: 10.1016/s0926-2040(99)00045-4

✦ Synopsis

In order to gain information about lignin molecular characteristics with a direct bearing on the remarkable susceptibility of some Austral hardwoods to biological delignification, milled-wood lignins were isolated and analyzed by spectroscopic 13 Ž 13 techniques in the solid state. Cross polarization and magic-angle spinning C nuclear magnetic resonance C CPMAS . Ž . NMR and Fourier-transform infrared FTIR spectra of the lignin preparations were obtained. The most diagnostic peaks were assigned and quantified as percentages of the total spectral area, and the differences observed discussed in terms of lignin composition. The spectral patterns obtained revealed that the woods from GeÕuina aÕellana, Eucryphia cordifolia and Nothofagus dombeyii have lignin with high syringylrguaiacyl ratio, as evidenced by relative areas of 13 C NMR signals at 153 and 148 ppm, and FTIR bands at 1335 and 1275 cm y1 . The presence of syringyl-rich lignins, characterized by lower redox potential and condensation degree than guaiacyl-rich lignins, could be a structural factor contributing to the ease of extensive delignification of these woods by white-rot fungi.