Abstract: The present invention describes isolation of plasmid DNA from bacteria. The addition of dyes to the alkaline lysis based purification buffers (P1, P2, and P3) allows for improved visual monitoring of the steps of preparing a bacterial lysate filtrate coupled to filtration or spin-column chromatography. The method comprises the suspending of the bacterial cells with buffer P1 (suspension is red/pink); lysing the bacteria with buffer P2 (suspension goes from red/purple color to translucent/purple); precipitating cellular debris with buffer P3 (solution becomes yellow with debris suspension); centrifuging or filtering to product a lysate filtrate; binding the lysate filtrate to a DNA binding matrix; washing; and isolating the plasmid via chromatography. The yield and quality of plasmid DNA is improved due to more consistent lysis. Errors in buffer addition are reduced by visualizing the color as buffers are added and also of changes in color of the preparation at each step.

Abstract: The present invention describes isolation of plasmid DNA or nucleic acid material from Escherichia coli (E. coli) or other species of microorganisms, or from other sources. The addition of indicator dyes to the alkaline lysis based purification buffers allows for increased ease of visual monitoring of the mixing and lysis steps of the procedure. The yield and quality of plasmid DNA is improved and the chance of error is reduced. The practice may be applied to other nucleic acid purification procedures.