Improving DNA plasmid production in Escherichia coli

Abstract

The ability to produce large quantities of plasmid DNA is imperative for wide scale availability of DNA vaccines. Large scale, high yield production relies on the synergy between host strain, plasmid, medium and production scheme. Screening as many variables as quickly and cost effectively as possible is the goal. In this study, Escherichia coli strains were transformed with two plasmids and screened for plasmid yield in shake flasks in chemically defined medium supplemented with either glucose or glycerol. High yield candidates were grown in feed batch fermentations at two specific growth rates, µ = 0.14 h and µ = 0.24 h. As predicted, high production in shake flasks was predictive of high production in fermentations. Using our media and process, we were able to reach volumetric yields of approximately 600 mg/L and specific yields of approximately 17.82 mg/g, regardless of growth rate. We were also able to increase productivity (mg/Lh) over 30%.