Establishment of purification process of pneumococcal capsular polysaccharide based on membrane chromatography

This study evaluated Natrix^® Q anion membrane chromatography for the purification of Streptococcus pneumoniae serotype 5 capsular polysaccharide (CPS) as an alternative to conventional organic solvent-based purification and bead-based ion-exchange chromatography. The purification process was optimized and characterized using a Design of Experiments (DoE) approach to establish a robust operating space for key process parameters. Under the optimized conditions, residual DNA was reduced to below 2%, while CPS recovery remained above 80%. The membrane process achieved a loading capacity of 45-60 mg CPS/mL membrane, approximately 4-6-fold higher than that of conventional anion-exchange resins (<10mg/mL), and operated at a residence time of approximately 6s, substantially shorter than the approximately 5 min typically required for bead-based ion-exchange chromatography. The CPS recovery was also higher than the previously reported range of 50%-73%. Scale-up studies further demonstrated that the optimized process could be successfully transferred to scale production. Product quality was evaluated by double immunodiffusion, proton nuclear magnetic resonance (¹H-NMR) spectroscopy, and relevant biochemical and physicochemical assays. The CPS purified by membrane chromatography met the predefined quality requirements. These results demonstrate that Natrix^® Q anion membrane chromatography provides an efficient, high-throughput, and scalable approach for the purification of serotype 5 pneumococcal CPS and has potential for application in large-scale pneumococcal polysaccharide vaccine manufacturing.