OFF-LINE QUANTITATIVE MONITORING OF PLASMID COPY NUMBER IN BACTERIAL FERMENTATION BY CAPILLARY-ELECTROPHORESIS

Capillary electrophoresis (CE) is an effective instrumental alternativ e to conventional slab gel electrophoresis in the determination of pla smid copy number during recombinant protein formation processes. This analytical setup provides efficient separation of different species of linearized plasmid molecules and quantification by UV detection. Both fused silica and gel-filled capillaries are assessed with respect to peak resolution and reproducibility. The application of coated capilla ries eliminates the electroosmatic flow to a large extent, resulting i n excellent separation of DNA fragments. The application of UV detecti on enables the analysis of linearized plasmid DNA with a conventional laboratory CE device. All investigated plasmids show good peak resolut ion due to their significant differences in molecular size, which is e ssential for sufficient separation of individual DNA molecules.