A Simplified Process for Purification and Refolding of Recombinant Human Interferon-α2b

Background: Interferon alpha-2b is a vital biotherapeutic produced through the recombinant DNA technology in E. coli. The recombinant IFN-alpha 2b normally appears as intercellular IBs, which requires intensive refolding and purification steps. Method: Purification of IFN-alpha 2b from solubilized IB was performed using two-phase extraction. To optimize refolding conditions, the effects of pH and different additives, including cysteine, cystine, urea, glycerol, Triton X-100, NaCl, and arginine, were investigated. Optimal refolding buffer (0.64 mM of urea, 5.57 mM of cysteine, and 1.8 mM of cystine) was obtained using RSM. The refolding process was performed by an optimized refolding buffer in the dilution and fed-batch refolding method at different protein concentrations (25-1000 mu g/mL). Result: At a final protein concentration of 500 mu g/mL, the fed-batch refolding method yielded in a biological activity of 2.24 x 10(8) IU/mg, which was nearly twice that of dilution method. Conclusion: Fed-batch refolding method resulted in the biologically active IFN-alpha 2b with high purity, which can be used for research and industrial purposes.