Patent ID: 7718791

Claim:
A process of reducing the protein content and preserving the capsular polysaccharide content in a complex cellular Streptococcus pneumoniae lysate broth, the process comprising the steps of: (a) growing bacterial cells of a selected S. pneumoniae serotype in a soy-based medium, which includes: (i) inoculating a first container containing the soy-based medium with seed stock of the selected serotype, and incubating the first container until growth requirements are met, (ii) inoculating a second container containing the soy-based medium with the culture from step (i) while maintaining a stable pH and temperature in the second container, and (b) lysing with a detergent the bacterial cells produced in step (a), thereby producing a cellular lysate containing soluble proteins, cell debris, nucleic acids and polysaccharide; (c) agitating the cellular lysate for a time sufficient to assure complete lysis and capsular polysaccharide release; (d) lowering the pH of the cellular lysate to between 4.5 and less than 5.5 to precipitate out the detergent and most of the soluble proteins, thereby producing a solution and a precipitate; (e) holding the solution and the precipitate formed in step (d) without agitation for a time sufficient to allow settling of the precipitate; and (f) processing the solution and the precipitate by centrifugation and/or filtration, whereby the capsular polysaccharide is preserved and the soluble protein is effectively reduced.