Patent ID: 7998732
Filing Date: 2011-08-16
Classification: C12N,C12P

Abstract:
1. A process for production of plasmid DNA comprising: (a) selecting a highly productive clonal subtype of a strain of (i) observing a phenotypic heterogeneity in a population of colonies generated by the transformed (ii) purifying said potentially highly productive clonal subtypes and determining the productivity of said purified, potentially highly productive clonal subtypes by measuring the plasmid copy number per cell; and, (iii) selecting as a highly productive clonal subtype a potentially highly productive clonal subtype that exhibits a higher plasmid copy number per cell in comparison to non-selected, transformed (b) cultivating said highly productive clonal subtype with fed-batch fermentation in chemically-defined medium in a fermentation volume of greater than 1000 L, wherein said phenotypic heterogeneity is observed after the transformed wherein the potentially highly productive clonal subtypes that represent the minor component of said phenotypic heterogeneity are gray colored-colonies while the major component of said phenotypic heterogeneity are white-colored colonies.