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.