The invention provides a separating and purifying process of
isochrysis galbana exopolysaccharide; and the process comprises the following steps of: preparing crude
isochrysis galbana exopolysaccharide by using
isochrysis galbana culturing solution as a
raw material; separating the crude isochrysis galbana exopolysaccharide ECPS by
ion exchange
chromatography, so as to obtain neutral
polysaccharide and acidic
polysaccharide components; loading the neutral
polysaccharide and acidic polysaccharide components on a gel column for
chromatography, so as to obtain eight components, wherein except for an ECPSII-A component, the quantities of the rest polysaccharide components are small; purifying the ECPSII-A component by using the gel
column chromatography, so as to obtain a single polysaccharide component; and depositing, freezing and
drying the single polysaccharide component by
ethanol so as to prepare pure exopolysaccharide ECPSIII. According to the invention, the separating and purifying process of the isochrysis galbana exopolysaccharide is established; and the process is simple and reasonable and has the advantages of stable reproducibility and good
operability. A good experiment basis is laid for follow-up study on
biological activity of the polysaccharide; moreover, the microalgae polysaccharide can be applied to the
medicine and medical field like other polysaccharide substances.