Structural diversity requires individual optimization of ethanol concentration in polysaccharide precipitation

Jun Xu, Rui-Qi Yue, Jing Liu, Hing-Man Ho, Tao Yi, Hu-Biao Chen*, Quan-Bin Han

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

112 Citations (Scopus)
163 Downloads (Pure)


Ethanol precipitation is one of the most widely used methods for preparing natural polysaccharides, in which ethanol concentration significantly affects the precipitate yield, however, is usually set at 70-80%. Whether the standardization of ethanol concentration is appropriate has not been investigated. In the present study, the precipitation yields produced in varied ethanol concentrations (10-90%) were qualitatively and quantitatively evaluated by HPGPC (high-performance gel-permeation chromatography), using two series of standard glucans, namely dextrans and pullulans, as reference samples, and then eight natural samples. The results indicated that the response of a polysaccharide's chemical structure, with diversity in structural features and molecular sizes, to ethanol concentration is the decisive factor in precipitation of these glucans. Polysaccharides with different structural features, even though they have similar molecular weights, exhibit significantly different precipitation behaviors. For a specific glucan, the lower its molecular size, the higher the ethanol concentration needed for complete precipitation. The precipitate yield varied from 10% to 100% in 80% ethanol as the molecular size increased from 1. kDa to 270. kDa. This paper aims to draw scientists' attention to the fact that, in extracting natural polysaccharides by ethanol precipitation, the ethanol concentration must be individually optimized for each type of material.

Original languageEnglish
Pages (from-to)205-209
Number of pages5
JournalInternational Journal of Biological Macromolecules
Early online date27 Mar 2014
Publication statusPublished - Jun 2014

Scopus Subject Areas

  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Economics and Econometrics
  • Energy(all)

User-Defined Keywords

  • Ethanol precipitation
  • Natural polysaccharides
  • Polysaccharide structures
  • Ethanol concentration


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