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).