Effect of ammonium chloride on plasmid DNA production in high cell density batch culture for biopharmaceutical use

In this paper the influence of ammonium salt concentration on the production of pharmaceutical grade plasmid DNA from unfed high cell density batch culture on synthetic glycerol media is presented. Ammonium chloride in different concentrations (0 mmol dm(-3), 18.7 mmol dm(-3), 37 mmol dm(-3) and 74 mmol dm(-3) supplemented) was used beside sodium glutamate as nitrogen source. Plasmid DNA concentrations of more than 50 mg dm(-3) were obtained with 37 mmol dm(-3) ammonium. The homogeneity of the DNA produced was confirmed by agarose and capillary gel electrophoresis and found to fulfil the quality requirements set for biopharmaceutical plasmid DNA with more than 90% in the supercoiled form. (C) 2003 Society of Chemical Industry.