The selection of optimum fermentation condition for improved expression of sumo-il11 in escherichia coli

Abstract

Escherichia coli is routinely used for the production of recombinant proteins for research purposes and for commercial applications. The level of intracellular accumulation of a recombinant protein is dependent on the final cell density and the specific activity of the protein. One of several strategies typically used to increase recombinant protein production is well control of fermentation condition. In our previous publication, we showed the preliminary expression of SUMO-IL11 protein in E. coli Rosetta 2. As expected, recombinant protein was well expressed as soluble form. However, the cell density at 600 nm was about 2 after 4 hours of IPTG induction. In this paper, we present the effect of fermentation factors on the expression level of SUMO-IL11 protein and cell density in E. coli Rosetta 2. SUMO-IL11 was highest expressed in TB owing to its rich medium and phosphate buffer for controlling pH fluctuation. The cell density and protein amount increased significantly when the cells were induced with 0.05 mM IPTG at 37^oC and the induction time of OD₆₀₀=2. Under these optimum conditions, the cell density increased 9,4 folds (OD₆₀₀=19.48 compared to 2.07). Protein amount of SUMO-IL11 synthesized by E. coli reached to 1.43 g/l or raised 14.3 folds. The SUMO-IL11 content accounted for 6.8% of the total protein in the cells.