A shortened process for producing a solution containing substantially purified capsular polysaccharides from a cellular Streptococcus pneumoniae lysate broth is described. Ultrafiltering and diafiltering a clarified S. pneumoniae lysate followed by pH adjustment to less than 4.5, preferably about 3.5, precipitated at least 98% of the protein in the solution without seriously affecting polysaccharide yield. Furthermore, following ultrafiltration and diafiltration and acidification to a pH of less than 4.5, filtration using activated carbon precipitated at least 90% of remaining protein without seriously affecting polysaccharide yield. Exemplary, non-limiting S. pneumoniae serotypes that can be purified using the 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 lysed using deoxycholate sodium (DOC), while in another embodiment the lytic agent is a non-animal derived lytic agent such as N-lauryl sarcosine sodium (NLS).
