Mechanical disruption of Escherichia coli for plasmid recovery

Five different mechanical cell disruption processes were evaluated as methods to extract plasmids from bacterial cells. The methods used were sonication, nebulization homogenization, microfluidization, and bead milling. The recovery yields of intact plasmids from the various methods were measured by quantitative gel electrophoresis. Bead milling and microfluidization were found to have the highest potential for large scale extraction with total intact recoveries of over 90% and around 50%, respectively. Other methods resulted in substantial plasmid degradation, with recoveries no greater than 20% of the total intact plasmid.