title: Structural characterization of guaiacyl-rich lignins in flax (Linum usitatissimum) fibers and shives.
abstract: The structural characteristics of the lignins from flax (Linum usitatissimum) fibers and shives were studied. Significant differences in the content and composition of the lignin from both parts were observed. The lignin contents were 3.8% in the fibers and 29.0% in the shives. Analysis by Py-GC/MS indicated a H:G:S molar ratio of 13:72:15 in the milled wood lignin (MWL) isolated from flax fibers and a molar ratio of 5:87:8 in the MWL isolated from flax shives. In addition, 2D-NMR showed a predominance of β-O-4' aryl ether linkages, followed by β-5' phenylcoumaran and β-β' resinol-type linkages in both MWLs, with a higher content of condensed linkages in flax shives. Thioacidolysis (followed by Raney nickel desulfurization) gave further information on the lignin units involved in the different linkages and confirmed the enrichment of G units. The thioacidolysis dimers released were similar from both lignins, with a predominance of the β-5' followed by β-1' and 5-5' structures.
authors: Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, P.O. Box 1052, E-41080 Seville, Spain. delrio@irnase.csic.es
authors: José C
authors: JC
authors: del Río
authors: Jorge
authors: J
authors: Rencoret
authors: Ana
authors: A
authors: Gutiérrez
authors: Lidia
authors: L
authors: Nieto
authors: Jesús
authors: J
authors: Jiménez-Barbero
authors: Ángel T
authors: ÁT
authors: Martínez
mesh_terms: D002236:Carbohydrate Conformation; D019281:Dimerization; D019597:Flax / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D008031:Lignin / Q000032:analysis / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy
chemical_list: D008031:Lignin