Improving Haemophilus influenzae Type b Polysaccharide Productivity Through Continuous Culture for Pentavalent Vaccine Manufacturing

Haemophilus influenzae type b (Hib) is a Gram-negative bacterium that causes severe infections in children under five, especially in developing countries. Although vaccination using capsular polysaccharide by Hib (linear polymer 5-D-ribitol-(1→1)-β-D-ribose-3-phosphate) conjugated to tetanus toxoid is effective, its production is complex and costly. This study aimed to develop a continuous production process for PRP to increase productivity, reduce batch numbers, and simplify manufacturing. Using a 1 L bioreactor, five dilution rates (0.13 to 0.32 h−1) were tested, with the best performance observed at 0.23 h−1, reaching a productivity of 167 mgL−1·h−1. Under optimized conditions, parameters such as free and immobilized PRP, glucose consumption, acetate formation, and biomass were monitored. The process yielded 874 mgL−1 of PRP after 74.4 h, with 78% in the free form and a final productivity of 165 mgL−1·h−1, approximately six times higher than batch processes and twice as high as fed-batch processes. The continuous process proved more efficient and required less infrastructure to meet production demands. However, further optimization is needed to enhance product quality and assess overall feasibility.