Optimization of Fermentation Conditions for Recombinant Human Interferon Beta Production by Escherichia coli Using the Response Surface Methodology

BACKGROUND The periplasmic overexpression of recombinant human interferon beta (rhIFN-β)-1b using a synthetic gene in Escherichia coli BL21 (DE3) was optimized in shake flasks using Response Surface Methodology (RSM) based on the Box-Behnken Design (BBD). OBJECTIVES This study aimed to predict and develop the optimal fermentation conditions for periplasmic expression of rhIFN-β-1b in shake flasks whilst keeping the acetate excretion as the lowest amount and exploit the best results condition for rhIFN-β in a bench top bioreactor. MATERIALS AND METHODS The process variables studied were the concentration of glucose as carbon source, cell density prior the induction (OD 600 nm) and induction temperature. Ultimately, a three-factor three-level BBD was employed during the optimization process. The rhIFN-β production and the acetate excretion served as the evaluated responses. RESULTS The proposed optimum fermentation condition consisted of 7.81 g L(-1) glucose, OD 600 nm prior induction 1.66 and induction temperature of 30.27°C. The model prediction of 0.267 g L(-1) of rhIFN-β and 0.961 g L(-1) of acetate at the optimum conditions was verified experimentally as 0.255 g L(-1) and 0.981 g L(-1) of acetate. This agreement between the predicted and observed values confirmed the precision of the applied method to predict the optimum conditions. CONCLUSIONS It can be concluded that the RSM is an effective method for the optimization of recombinant protein expression using synthetic genes in E. coli.