Abstract This study describes an efficient production and purification system developed for large-scale production of biologically active recombinant dengue virus type 3 envelope domain III (rDen 3 EDIII) protein. Process optimization was carried out at small scale for enhancement of recombinant protein production. Under the optimized conditions, 100L pilot-scale fermentation was carried out to produce a large amount of biomass for purification. The recombinant protein was renatured using an on-column refolding process. This protein was purified using affinity and cation exchange chromatography processes. Approximately 29 mg of pure and biologically active rDen 3 EDIII protein were obtained per gram of dry cell weight. The purified protein was used for immunization in mice. Biochemical characterization of purified rDen 3 EDIII protein was performed by Western blotting and enzyme-linked immunosorbent assays (ELISA). The results demonstrated that the purified rDen 3 EDIII protein could react with anti-Den 3...