A process for the recovery of plasmids or other DNA from cells using a
first filtration step to remove the cellular debris and other large
cellular components and then an ultrafiltration step to capture the
plasmids or other DNA on the surface of the ultrafiltration membrane
where they may be recovered. An apparatus is also taught for enacting the
process and comprises an upper microfiltration or coarse filtration
membrane and a lower ultrafiltration membrane. The driving force may be
the same for both filters or different and may be done sequentially or
simultaneously.