Improvement of Large-scale PRP production by Haemophilus influenzae typeb, using modified CY medium

Haemophilus influenzae type b (Hib) is a gram negative bacterium and one of the most common causative agents of acute meningitis in infants and less than 5 years old children worldwide. The production of Hib capsular polysaccharide; polyribosyl ribitolphosphate (PRP) is important for the production of conjugate vaccines against Hib infections. The aim of this study is the improvement of Large-scale PRP production by Hib. Haemophilus influenzae type b standard strain ATCC10211 was cultivated in 2L fermentors contain 1.5L CY (casaminoacid yeast extract) medium with normal or modified concentrations of glucose, yeast extract, hemin and NAD (nicotinamide adenine dinucleotide). Seed culture of two fermentors was inoculated to 50 L fermentor, separately and range of PRP production and Dry cell weight (DCW) were studied. Cultivation of Hib in 50L fermentor contained modified CY medium with 6gl-1 Glucose, 2.5 gl-1 Yeast extract, 0.03 gl-1 Hemin and 0.015 gl-1 NAD, with controlled pH at 7.3 and 30% Dissolved oxygen tension (DOT) resulted to about 5.1 gl-1 DCW and 1.16 gl-1 PRP, that was significantly higher than normal CY medium. In conclusion, by modification in some medium components of CY medium, control of Dissolved oxygen tension and pH, the Large-scale production of PRP is improved. Improvement of PRP production leads to reduce the final cost of Hib conjugate vaccines.