Quantification of lignin-carbohydrate linkages with high-resolution NMR spectroscopy
Quantification of lignin-carbohydrate linkages with high-resolution NMR spectroscopy
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DOI：
10.1007/s00425-011-1359-2
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发表时间：
2011-06-01
期刊：
影响因子：
4.3
通讯作者：
Jameel, Hasan
中科院分区：
文献类型：
--
作者：
Balakshin, Mikhail;Capanema, Ewellyn;Jameel, Hasan
开发了一种结合定量(13)C核磁共振和HSQC 2D核磁共振技术来表征木质素-碳水化合物复合体(LCC)键的定量方法。从火炬松和白桦木材中提取粗磨木素(MWLc)、冰醋酸提取粗磨木素(LCC-ACoH)和纤维素酶木质素(CEL)，并用此方法在常规300 MHz核磁共振波谱仪和950 MHz低温探头波谱仪上进行了表征。阐明了不同类型(MWL、CEL和LCC-ACoH)的松木和桦木LCC制剂的结构差异。配备低温探头的高场核磁共振谱仪的使用显著提高了LCC信号的分辨率，因此，对LCC键的准确定量是至关重要的。所研究的制剂显示存在不同量的苄基醚、伽玛酯和苯苷LCC键。未检测到苄基酯基团。松木LCC-ACoH和桦木MWLc是分析松木和桦木苯苷和酯LCC键的较佳选择，而CEL则是研究苯基醚LCC结构的最佳选择。数据表明，与桦木相比，松材含有更多的苯基醚LCC键，但苯苷和伽玛酯LCC部分含量较低。
A quantitative approach to characterize lignin-carbohydrate complex (LCC) linkages using a combination of quantitative (13)C NMR and HSQC 2D NMR techniques has been developed. Crude milled wood lignin (MWLc), LCC extracted from MWLc with acetic acid (LCC-AcOH) and cellulolytic enzyme lignin (CEL) preparations were isolated from loblolly pine (Pinus taeda) and white birch (Betula pendula) woods and characterized using this methodology on a routine 300 MHz NMR spectrometer and on a 950 MHz spectrometer equipped with a cryogenic probe. Structural variations in the pine and birch LCC preparations of different types (MWL, CEL and LCC-AcOH) were elucidated. The use of the high field NMR spectrometer equipped with the cryogenic probe resulted in a remarkable improvement in the resolution of the LCC signals and, therefore, is of primary importance for an accurate quantification of LCC linkages. The preparations investigated showed the presence of different amounts of benzyl ether, gamma-ester and phenyl glycoside LCC bonds. Benzyl ester moieties were not detected. Pine LCC-AcOH and birch MWLc preparations were preferable for the analysis of phenyl glycoside and ester LCC linkages in pine and birch, correspondingly, whereas CEL preparations were the best to study benzyl ether LCC structures. The data obtained indicate that pinewood contains higher amounts of benzyl ether LCC linkages, but lower amounts of phenyl glycoside and gamma-ester LCC moieties as compared to birch wood.