The available pneumococcal conjugate vaccines provide protection against
only those serotypes that are included in the vaccine, which leads to a
selective pressure and serotype replacement in the population. An
alternative low-cost, safe and serotype-independent vaccine was
developed based on a non-encapsulated pneumococcus strain. This study
evaluates process intensification to improve biomass production and
shows for the first time the use of perfusion-batch with cell recycling
for a bacterial vaccine production. Batch, fed-batch and perfusion-batch
were performed at 10 L scale using a complex animal component-free
culture medium. Cells were harvested at the highest optical density,
concentrated and washed using microfiltration or centrifugation to
compare cell separation methods. Higher biomass was achieved using
perfusion-batch, which removes lactate while retaining cells. The
biomass produced in perfusion-batch would represent at least 4-fold
greater number of doses per cultivation than in the previously described
batch process. Each strategy yielded similar vaccines in terms of
quality as evaluated by Western blot and animal immunization assays,
indicating that, so far, perfusion-batch is the best strategy for the
intensification of pneumococcal whole cell vaccine production, since it
can be integrated to the cell separation process keeping the same
vaccine quality.