Abstract
            Purposes: Solubilization of inclusion bodies expressed in E. coli is a critical step during  manufacturing of recombinant proteins expressed as inclusion bodies. So far, various methods  have been used for solubilization and purification of inclusion body proteins to obtain active  proteins with high purity and yield. The aim of this study was to examine the benefit of organic  solvents such as alcohols in solubilization of recombinant interferon β-1b inclusion bodies.  
  Methods: Effect of important parameters inclusion pH, concentration and type of denaturant  and concentration of alcoholic solvents were optimized to formulate a suitable solubilization  buffer and investigate their effect on solubilization of interferon β-1b inclusion bodies.  
  Results: Our findings showed the acidic pH in the range of 2-3 is more suitable than alkaline pH  >12 for solubilization and achieving higher content of interferon β-1beta and pure recombinant  protein. We have also demonstrated that 1% SDS acts better than 2M urea to solubilize Inclusion  body proteins of interferon β-1b at pH of 2-3. The interferon concentration was 2.35 mg per 100  mg IB when we used 40% (v/v) 1-propanol and 20% (v/v) 2-butanol into the buffer solution as  well.  
  Conclusion: The optimized method provides gentile condition for solubilization of inclusion  body at high protein concentration and purity with a degree of retention of native secondary  structure which makes this method valuable to be used in production and research area.