The invention discloses a method for purifying bacterial capsular
polysaccharide. The method comprises the following steps: treating a
streptococcus pneumonia
fermentation culture solution with an inactivator, adding acid for regulating the pH value to be less than or equal to 6.5, precipitating impurities, centrifuging, and carrying out
microfiltration for removing precipitates, so that
polysaccharide clarified liquor is obtained; carrying out
ultrafiltration liquid change on the
polysaccharide clarified liquor by adopting a membrane with the molecular weight
cut-off of 10-100KDa and concentrating, and carrying out
chromatography on the obtained capsular polysaccharide solution by combining compound type
ion exchange
chromatography and hydroxyl
phosphate grey salt
chromatography, so that the purified capsular polysaccharide solution is obtained; and concentrating and carrying out
ultrafiltration on the capsular polysaccharide solution, and carrying out
sterile filtration and storing. By combining the compound type
ion exchange chromatography and the hydroxyl
phosphate grey salt chromatography, the contents of
protein and
nucleic acid impurities can be effectively reduced to be lower than 1%, the quality of a purified polysaccharide product is higher than European Union
pharmacopoeia standard requirements, and the
recovery rate is more than 60%. The method disclosed by the invention has the advantages that the technology is simple and rapid, the enlargement is easy, and industrial production can be realized.