Over-production of human interferon-γ by HCDC of recombinant Escherichia coli

A simple fed-batch process was developed using a modified variable specific growth rate feeding strategy for high cell density cultivation of Escherichia coli BL21 (DE3) expressing human interferon-gamma (hIFN-γ). The feeding rate was adjusted to achieve the maximum attainable specific growth rate during fed-batch cultivation. In this method, specific growth rate was changed from a maximum value of 0.55 h−1 at the beginning of feeding and then it was reduced to 0.4 h−1 at induction time. The final concentration of biomass and IFN-γ was reached to ∼115 g l−1 (DCW) and 42.5 g(hIFN-γ) l−1 after 16.5 h, also the final specific yield and overall productivity of recombinant hIFN-γ (rhIFN-γ) were obtained 0.37 g(hIFN-γ) g−1 DCW and 2.57 g(hIFN-γ) l−1 h−1, respectively. According to available data this is the highest specific yield and productivity that has been reported for recombinant proteins production yet.