Instituto de Recursos Naturales y Agrobiologia de Sevilla, CSIC, PO Box 1052, E-41080 Seville, Spain.
J Agric Food Chem. 2009 Nov 11;57(21):10271-81. doi: 10.1021/jf900815x.
The structural characteristics of the lignin from jute (Corchorus capsularis ) fibers, which are used for high-quality paper pulp production, were studied. The lignin content (13.3% Klason lignin) was high compared to other nonwoody bast fibers used for pulp production. The lignin structure was characterized by pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), 2D-NMR, and thioacidolysis. Upon Py-GC/MS, jute fibers released predominantly products from syringylpropanoid units with the S/G ratio being 2.1 and a H/G/S composition of 2:33:65. 2D-NMR of the milled wood lignin (MWL) isolated from jute fibers showed a predominance of beta-O-4' aryl ether linkages (72% of total side chains), followed by beta-beta' resinol-type linkages (16% of total side chains) and lower amounts of beta-5' phenylcoumaran (4%) and beta-1' spirodienone-type (4%) linkages and cinnamyl end groups (4%). The high predominance of the S-lignin units, together with the high proportion of beta-O-4' aryl ether linkages, which are easily cleaved during alkaline cooking, are advantageous for pulping. On the other hand, a small percentage (ca. 4%) of the lignin side chain was found to be acetylated at the gamma-carbon, predominantly over syringyl units. The analysis of desulphurated thioacidolysis dimers provided additional information on the relative abundances of the various carbon-carbon and diaryl ether bonds and the type of units (syringyl or guaiacyl) involved in each of the above linkage types. Interestingly, the major part of the beta-beta' dimers included two syringyl units, indicating that most of the beta-beta' substructures identified in the HSQC spectra were of the syringaresinol type (pinoresinol being absent), as already observed in the lignin of other angiosperms.
研究了用于生产高质量纸浆的黄麻（Corchorus capsularis）纤维中木质素的结构特征。与用于制浆的其他非木质韧皮纤维相比，黄麻的木质素含量（13.3% Klason 木质素）较高。木质素结构通过热解气相色谱/质谱联用（Py-GC/MS）、二维核磁共振（2D-NMR）和硫代酸解进行了表征。通过 Py-GC/MS，黄麻纤维主要释放出愈创木基丙烷单元的产物，S/G 比为 2.1，H/G/S 组成为 2:33:65。从黄麻纤维中分离出的磨木木质素（MWL）的 2D-NMR 显示，β-O-4'芳基醚键（占总侧链的 72%）占主导地位，其次是β-β'树脂醇型键（占总侧链的 16%），β-5'苯基香豆素（占 4%）和β-1'螺二烯酮型（占 4%）键和肉桂基端基（占 4%）的含量较低。S-木质素单元的高优势，以及β-O-4'芳基醚键的高比例，这些键在碱性蒸煮过程中很容易断裂，有利于制浆。另一方面，木质素侧链的一小部分（约 4%）被γ-碳乙酰化，主要是在愈创木基单元上。脱硫硫代酸解二聚体的分析提供了有关各种碳-碳和二芳基醚键的相对丰度以及参与每种键类型的单元（愈创木基或愈创木基）的信息。有趣的是，β-β'二聚体的主要部分包括两个愈创木基单元，这表明在 HSQC 谱中鉴定的大多数β-β'亚结构是丁香脂素型（不存在松柏脂素），这与其他被子植物木质素中观察到的情况一样。
