Enzymic degradation of hydroxyethyl cellulose and analysis of the substitution pattern along the polysaccharide chain
Enzymic degradation of hydroxyethyl cellulose and analysis of the substitution pattern along the polysaccharide chain
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DOI：
10.1016/j.carbpol.2017.02.089
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发表时间：
2017-08-01
影响因子：
11.2
通讯作者：
Ran, Rong
中科院分区：
文献类型：
--
作者：
Diao, Yongfu;Song, Mingwei;Ran, Rong
研究了不同摩尔取代度(MS)的羟乙基纤维素(HEC)样品的酶降解行为。采用核磁共振、傅里叶变换红外光谱、X射线衍射仪和扫描电子显微镜等技术研究了酶处理前后HEC分子结构的变化，并用粘度法研究了HEC的降解动力学。从FTIR和动力学结果可以观察到HEC链的断裂。此外，通过凝胶渗透色谱(GPC)分析了酶降解过程中聚合物的相对分子质量(MW)和释放的葡萄糖浓度的降低。这些结果表明，MS较低的HEC更容易降解，这为更好地理解纤维素酶降解HEC的作用机理提供了依据。此外，通过完全降解和定量释放的葡萄糖，研究了取代指数(SI)和取代基在HEC链上的分布。结果表明，HEC样品的羟乙基摩尔取代(MS)和羟乙基可能的分布有所不同。令人印象深刻的是，我们的努力建立了一种简便的分析方法，用于阐明取代基在HEC链上的分布。(C)2017爱思唯尔有限公司。保留所有权利。
The enzymatic degradation behavior of hydroxyethyl cellulose (HEC) samples with different molar substitutions (MS) values was investigated. The changes in the molecular structure of HEC treated with enzymatic approach in comparison to the native HEC were studied through nuclear magnetic resonance (NMR), fourier transform infrared spectra (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques and kinetics of degradation was studied by viscometry. The cleavage of HEC chains could be observed from FTIR and kinetics results. Moreover, reduce in molecular weight (Mw) of polymer and liberated glucose concentration was investigated by gel permeation chromatography (GPC) analysis during enzymatic degradation. And all these results indicated that HEC with lower MS is more susceptible to degrade and provided a better understanding of the mechanism operating during enzymatic hydrolysis of HEC by cellulases. Furthermore, by complete degradation and quantification of liberated glucose, the substitution index (SI) and the distribution of substituents along the HEC chain were investigated. The results suggested that the HEC samples differed in hydroxyethyl molar substitutions (MS) and possible distribution of the hydroxyethyl groups. Impressively, our efforts established a facile analytical method for the elucidation of the distribution of substituents along the HEC chain. (C) 2017 Elsevier Ltd. All rights reserved.