Optimization of culture conditions for a synthetic gene expression in Escherichia coli using response surface methodology: The case of human interferon beta

A human interferon beta (hINF-β) synthetic gene was optimized and expressed in Escherichia coli BL21-SI using a vector with the T7 promoter. To determine the best culture conditions such as culture medium, temperature, cell density and inducer concentration, we used the response surface methodology and a Box-Behnken design to get the highest hINF-β production. The maximum hINF-β production of 61 mg l−1 was attained using minimum medium and the following predicted optimal conditions: temperature of 32.5 °C, cell density of 0.64, and inducer concentration of 0.30 M NaCl. This is the first report showing the successful performance of the BL21-SI system in a minimum medium. The response surface methodology is effective for the optimization of recombinant protein production using synthetic genes.