Separation of water-soluble polysaccharides from Cyclocarya paliurus by ultrafiltration process.

In this study, ultrafiltration membrane process was employed to separate polysaccharides from Cyclocarya paliurus (Batal.) Iljinskaja (C. paliurus) to simulate industrial production. Meanwhile, the molecular weight distribution of C. paliurus polysaccharides was investigated by gel permeation chromatography. Four fractions were obtained and named as CPPS-A, CPPS-B, CPPS-C and CPPS-D, respectively. CPPS-A and CPPS-B contained approximately 69.5% and 12.7% of polysaccharides, whose molecular weight were in the range of 100-300 kDa and 120 kDa, respectively. CPPS-C was comprised of two polysaccharides with average molecular weight of 40 kDa and 15 kDa. Results showed that ultrafiltration resulted in the removal of parts of small molecule weight polysaccharides, the increase of proportion of high molecule weight ones and the obvious improvement of quality of products. Compared with ethanol precipitation and gel permeation chromatography techniques, ultrafiltration showed many advantages, and also provided theoretical support for industrial manufacturing of C. paliurus polysaccharides in separation.