The present invention relates to a novel process of production of purified recombinant cholera toxin B (rCTB) which provides protection against diarrhea caused by various bacteria such as Vibrio cholerae and Enterotoxigenic Escherichia coli (ETEC). More particularly, the present invention relates to a process of production of rCTB with significantly higher yield and higher purity. The present invention also relates to a vaccine formulation having synergistic protection against Vibrio cholerae and cross protection against ETEC.
