Biochemical engineering approaches to the challenges of producing pure plasmid DNA

Plasmid-based genes offer promise for a new generation of vaccines and for gene therapy, but the size and character of plasmids pose new challenges to biochemical engineers. By acknowledging these and using bioprocess-design information based on fundamental studies of the system's properties, it wil l be possible to create efficient and consistent processes for these materi als. This review addresses the purity required, the key issue of the sensit ivity of the chromosomal DNA contaminant and larger plasmids to hydrodynami c forces, and the impact of this and other characteristics of plasmids on t he recovery and purification of DNA for pharmaceutical purposes.