Elucidation of the structure of cellulolytic enzyme lignin
Elucidation of the structure of cellulolytic enzyme lignin
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DOI：
10.1515/hf.2006.061
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发表时间：
2006-07-01
期刊：
影响因子：
2.4
通讯作者：
Kadla, John F.
中科院分区：
文献类型：
--
作者：
Hu, Zhoujian;Yeh, Ting-Feng;Kadla, John F.
通过三种不同的球磨方法制备纤维素分解酶木质素（CEL）和磨碎的木材木质素（MWL）。使用湿化学分析、FTIR 和溶液态 NMR 技术阐明了不同产率的 CEL 结构，并与 MWL 进行了比较。结果表明，木材球磨会降解木质素中的 β-O-4 结构。然而，即使经过大量球磨，仍有不到 25% 的 β-O-4 结构被降解。软木木质素的降解程度小于硬木木质素。可提取木质素产量（MWL 或 CEL）是评估球磨程度和效果的最佳方法。 CEL 优于 MWL，因为它可以以更高的产率分离且降解更少。 CEL 的分离产率范围为 20% 至 86%。在此范围内，CEL 具有相似的结构，表明次生壁中的木质素结构均匀。残留酶木质素（REL）在结构上与CEL不同，可能主要来源于中层。在本文中，我们提出了一种分离木质素用于结构研究的新程序，其中木材被充分研磨并连续提取以产生代表木材中总木质素的三种木质素部分。
Cellulolytic enzyme lignin (CEL) and milled wood lignin (MWL) were prepared by three different ball-milling methods. The structure of CEL at various yields was elucidated and compared with MWL using wet chemical analysis, FTIR and solution-state NMR techniques. Results show that ball milling of wood degrades beta-O-4 structures in lignin. However, even after extensive ball milling, less than 25% of the beta-O-4 structures were degraded. The extent of degradation was less for softwood than for hardwood lignin. Extractable lignin yield, either MWL or CEL, was the best way to assess the extent and effect of ball milling. CEL is preferred over MWL, as it can be isolated in higher yield with less degradation. CEL was isolated at yields ranging from 20% to 86%. Over this range the CEL had similar structures, suggesting that lignin in the secondary wall is uniform in structure. The residual enzyme lignin (REL) was structurally different from CEL and may originate mainly from the middle lamella. In this paper we propose a new procedure for the isolation of lignin for use in structural studies, whereby wood is sufficiently milled and successively extracted to produce three lignin fractions representing the total lignin in wood.