A shortened process for producing a solution containing substantially purifiedcapsular polysaccharides from a cellular Streptococcus pneumoniae lysatebroth is described. Ultrafiltering and diafiltering a clarified S. pneumoniaelysate followed by pH adjustment to less than 4.5, preferably about 3.5, precipitatedat least 98% of the protein in the solution without seriously affecting polysaccharideyield. Furthermore, following ultrafiltration and diafiltration and acidificationto a pH of less than 4.5, filtration using activated carbon precipitated at least90% of remaining protein without seriously affecting polysaccharide yield.Exemplary, non-limiting S. pneumoniae serotypes that can be purified usingthe shortened process of the invention are 1, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A,19F, and 23F. In one embodiment, the Streptococcus pneumoniae cells are lysedusing deoxycholate sodium (DOC), while in another embodiment the lytic agentis a non-animal derived lytic agent such as N-lauryl sarcosine sodium (NLS).
