Polysaccharide Production in Pilot Scale Bioreactor Cultivations of Neisseria meningitidis Serogroup C

Serogroup C polysaccharide from Neisseria meningitidis (PS) constitutes the antigen for the respective vaccine production. In order to investigate the enhancement of the final PS concentration (P(f)), as well as the overall yield factor (PS/biomass) (Y(P/X)), 13 total cultivations distributed in 6 series (from A to F) were carried out in Frantz medium (40 L plus inoculum) in a 80L bioreactor at 35(o)C, 0.4 atm, 120 rpm, airflow rate of 5 L/min and K(L)a = 4.2 h(-1). The series (A-F) correspond to different experimental conditions as follows: A) without pH and dissolved O(2) controls; B) pH control at 6.5; C) pH control at 6.5 and glucose pulse at the 10(th) hour; D) dissolved O(2) control at 10% saturation value; E) pH control at 7.4; F) dissolved O(2) limitation (set rotation at 55 rpm). Concentrations of dry biomass, PS, cellular nitrogen, residual glucose, organic and inorganic nitrogen in the medium were measured. The best results were represented by series A (averages of P(f) = 0.15 g/L and Y(P/X) = 107 mg/g). The presented findings could be useful for a proper Frantz medium reformulation in order to obtain a greater amount of PS and improve the vaccine development in industrial scale-up production.