Evaluation of capsular Polysaccharide production by Haemophilus Influenzae type B in different culture media

Abstract

Haemophilus influenzae b (Hib), an encapsulated Gram-negative coccobacillus, is one of the most common agents of meningitis worldwide. The Hib vaccine is included in the routine immunization schedule of several countries. The capsular polysaccharide, Poliribosyl-Ribitol-Phosphate (PRP), conjugated to a carrier protein is the antigen of the vaccine against Hib. Currently in industrial processes, Hib is cultivated in a soy peptone and yeast-extract based complex medium (MMP). This work aimed to evaluate whether a chemically defined medium could replace the MMP medium in the PRP production. The use of a defined media could offer several advantages in the whole process and would be of great interest to the industrial PRP production in vaccination programs. The PRP production ranged from 100 to 290 mg L-1 in the studied semi-defined and defined media. The formulation of several chemically defined media based on literature led to a promising composition as is the case of medium G which presented a production of 295 mg PRPL-1 with a lower biomass value of 4.8 UA (O.D.540 nm) when compared to MMP medium with 395 mg PRPL-1 and 6.45 UA respectively.