Abstract: A process for reducing the protein content and preserving the capsular polysaccharide content in a complex cellular Streptococcus pneumoniae lysate broth prior to purification is described. Utilizing pH reduction after cellular lysis has resulted in a purified polysaccharide that consistently meets the protein specification, and higher recovery yields of polysaccharide during the purification process.

Abstract: The present invention provides improved methods for the reduction or removal of protein impurities from a complex cellular Streptococcus pneumoniae lysate or centrate comprising serotype 3 polysaccharides involving steps relating to post-lysis heating or pH adjustment. In certain methods, the lysate is heated for a time and at a temperature sufficient to denature proteins present in the lysate and cause their aggregation and precipitation. In one embodiment, the lysate is heated to at least 60° C. for at least 30 minutes to cause protein aggregation and precipitation, more particularly about 60° C. to about 70° C. for about 30 to about 50 minutes, and even more particularly about 65° C. for about 40 minutes. In other methods, the pH of the lysate or centrate is increased to at least 8.0 to improve filterability, more particularly about 8.0 to 8.4, and even more particularly about 8.2.

Abstract: A process for reducing the protein content and preserving the capsular polysaccharide content in a complex cellular Streptococcus pneumoniae lysate broth prior to purification is described. Utilizing pH reduction after cellular lysis has resulted in a purified polysaccharide that consistently meets the protein specification, and higher recovery yields of polysaccharide during the purification process.