Background

Almost all natural polysaccharides have wide molecular weight distribution and the complex heterogeneous polysaccharides may also exhibit variations in proportions of sugar constituents, linkage type, degree and arrangement of branching or degree of substitution. The heterogeneity of molecular weight and chemical structure restricts basic research and application of polysaccharides. Therefore, it is meaningful to fractionate polysaccharides into fractions with high homogeneity in molecular weight and chemical structure.

Scope and approach

Compared with chromatography and ultrafiltration, gradient non-solvent precipitation is inexpensive, has a wide application scope and can be easily scaled up or down as required. Therefore, this work reviews fractionation of polysaccharides by gradient non-solvent precipitation. Specifically, this work describes the commonly used non-solvents, fractionation mechanism of gradient non-solvent precipitation, how to establish the fractionation procedure, assessment of the fractionation effect and factors that affect fractionation.

Key findings and conclusions

This paper provides comprehensive and detailed directions for how to fractionate a new polysaccharide using this method. It is suggested to select a suitable non-solvent and establish the fractionation procedure according to the curve of the polysaccharide recovery as a function of the non-solvent concentration. Fractionation by gradient non-solvent precipitation is based on the difference in solubility of polysaccharides. Therefore, fractionation may be affected by the precipitation conditions and those factors that can affect the solubility of polysaccharides. During fractionation, those factors that negatively affect fractionation should be strictly controlled.

中文翻译：

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梯度非溶剂沉淀法分离多糖的研究进展

背景

几乎所有天然多糖都具有较宽的分子量分布，并且复杂的异质多糖也可能在糖成分的比例，连接类型，支化程度和排列方式或取代度方面表现出差异。分子量和化学结构的异质性限制了多糖的基础研究和应用。因此，有意义的是将多糖分级为分子量和化学结构均一性高的级分。

范围和方法

与色谱和超滤相比，梯度非溶剂沉淀法价格便宜，适用范围广，并可根据需要轻松按比例放大或缩小。因此，这项工作回顾了通过梯度非溶剂沉淀法分离多糖的方法。具体来说，本文描述了常用的非溶剂，梯度非溶剂沉淀的分馏机理，如何建立分馏程序，评估分馏效果以及影响分馏的因素。

主要发现和结论

本文为如何使用这种方法分离新多糖提供了全面而详细的指导。建议根据多糖回收率随非溶剂浓度变化的曲线，选择合适的非溶剂并建立分馏程序。通过梯度非溶剂沉淀进行分级分离是基于多糖的溶解度差异。因此，分馏可能受到沉淀条件和那些可能影响多糖溶解度的因素的影响。分馏期间，应严格控制那些对分馏产生负面影响的因素。