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首页> 外文期刊>Journal of Wood Chemistry and Technology >HOW WELL DO MWL AND CEL PREPARATIONS REPRESENT THE WHOLE HARDWOOD LIGNIN?
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HOW WELL DO MWL AND CEL PREPARATIONS REPRESENT THE WHOLE HARDWOOD LIGNIN?

机译：MWL和CEL制剂在整个硬木中的表现如何？

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Hardwood lignin preparations were isolated using classical milled wood lignin (MWL) and cellulolytic enzyme lignin (CEL) protocols. Furthermore, we managed to produce a lignin preparation of a very high yield, above 90%, with high purity and minimal structural degradation. This was achieved by dissolution and regeneration of milled wood prior to enzymatic hydrolysis, along with the use of 80% dioxane for lignin extraction. This preparation (RCEL-80) yield was about 4.5 and 2.5 times higher than the yields of the traditional MWL and CEL preparations, correspondingly, at the same milling time. The preparations obtained were comprehensively analyzed with state-of-the-art quantitative NMR techniques and wet chemistry methods. CELs were representative preparations for hardwood lignins as the S/G ratios in the CELs were equivalent to those in lignin in situ. Degradation of the main lignin subunits was very low. Importantly, the structures of CELs were independent of the preparation yield and were very similar to the structure of the high-yield lignin, RCEL-80. In contrast, the structures of MWLs were noticeably dependent on the preparation yield, especially when the yield was below 15-20% of total wood lignin. In particular, the S/G ratio increased with increasing MWL yield, but was still lower than the S/G ratios of the whole lignins in situ, even at high MWL yields. The amounts of beta-O-4 lignin units in MWL were lower than those in the corresponding CEL preparations. It has been concluded that CEL preparations were representative of the whole wood lignin whereas MWLs represent a fraction with a lower S/G ratio.
机译：硬木木质素制剂使用经典磨木木质素（MWL）和纤维素分解酶木质素（CEL）方案分离。此外，我们设法生产了产率很高（高于90％），具有高纯度和最小的结构降解的木质素制剂。这是通过在酶促水解之前将经过碾磨的木材溶解和再生，以及将80％二恶烷用于木质素提取来实现的。在相同的研磨时间下，该制剂（RCEL-80）的产率分别是传统MWL和CEL制剂的产率的约4.5和2.5倍。使用最新的定量NMR技术和湿化学方法对获得的制剂进行了全面分析。 CEL是硬木木质素的代表性制备方法，因为CEL中的S / G比与原位木质素中的S / G比相同。主要木质素亚基的降解非常低。重要的是，CEL的结构与制备产率无关，并且与高产率的木质素RCEL-80的结构非常相似。相反，MWLs的结构明显取决于制剂的收率，特别是当收率低于总木素的15-20％时。特别地，S / G比随MWL产率的增加而增加，但是即使在高MWL产率下，仍比原木质素整体的S / G比低。 MWL中β-O-4木质素单元的数量低于相应CEL制剂中的数量。已经得出结论，CEL制剂代表了整个木素木质素，而MWL则代表了较低的S / G比。

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