Enhancement of human gamma-interferon production in recombinant E. coli using batch cultivation

Development of inexpensive and simple culture media and appropriate induction conditions are always favorable for industry. In this research, chemical composition and stoichiometric data for gamma-interferon production and recombinant Escherichia coli growth were used in order to achieve a simple medium and favorable induction conditions. To achieve this goal, the effects of medium composition and induction conditions on the production of gamma-interferon were investigated in batch culture of E. coli BL21 (DE3) [pET3a-ifngamma]. These conditions were considered as suitable conditions for the production of gamma-interferon: 2.5x M9 medium, supplemented with a mixture of amino acids (milligram per liter), including glutamic acid 215, aspartic acid 250, lysine 160, and phenylalanine 90, and induction at late-log phase (OD(600) = 4.5). Under these conditions, dry cell weight of 6 +/- 0.2 g/l and gamma-interferon concentration of 2.15 +/- 0.1 g/l were obtained. Later, without changing the concentration ratio of amino acids and glucose, the effect of increase in the primary glucose concentration on productivity of gamma-interferon was investigated. It was found that 25 g/l glucose will result in maximum attainable biomass and recombinant human gamma-interferon. At improved conditions, a dry cell weight of 14 +/- 0.2 g/l, concentration and overall productivity of gamma-interferon 4.2 +/- 0.1 g/l and 420 +/- 10 mg/l h, respectively, were obtained.