Production of recombinant human interferon gamma by batch fermentation in E. coli system

To improve the expression of recombinant human interferon gamma (rhIFN-γ) protein in 
recombinant E. coli Rosetta DE3 bacterial cells, the effect of different factors for the over
production of rhIFN-γ, including type of culture media, pH and type of inducer, has been evaluated 
in experimental shaking flasks. A simple batch fermentation process was carried out and the growth 
rate of recombinant E. coli Rosetta DE3 has been monitored using optical density measurements 
and wet cell weight. The LB medium was used and the dissolved oxygen level was maintained at 30
40% of air saturation, by control of the inlet air and agitation rate. The pH of media was sustained 
at pH 7.  The inducer was lactose at 2mM final concentration, added after 3 h fermentation, and the 
stationary phase of growth started at 9 h of batch process.  The final cell weight of the batch 
fermentation was 7g/l media after 12 h of starting process. The immunogenicity of rhIFN-γ protein 
has been tested against the rabbit polyclonal human interferon antibodies by western blot analysis. 
Based on these small-scale experiments, optimum operating conditions were chosen to scale up a 
better pilot process production of rhIFN-γ protein.