Cell Lysis: Bacterial cells are lysed using a lysis buffer containing sodium dodecyl sulfate (SDS) and sodium hydroxide (NaOH), which disrupts the cell membrane and releases cellular components.

Denaturation: The alkaline conditions denature both plasmid and chromosomal DNA. Plasmid DNA, being smaller and circular, remains intact, while larger chromosomal DNA becomes entangled and precipitates out.

Neutralization: A neutralizing solution, typically potassium acetate, is added to restore the pH. This causes denatured chromosomal DNA and proteins to precipitate, while plasmid DNA stays in solution.

Centrifugation: The mixture is centrifuged, separating the precipitated debris from the plasmid DNA in the supernatant.

Purification: The plasmid DNA is further purified through methods like ethanol precipitation or silica column purification to eliminate contaminants.

Culture Preparation: Grow E. coli containing the plasmid in LB medium with appropriate antibiotics overnight.

Cell Harvesting: Centrifuge the culture to collect the bacterial pellet.

Resuspension: Resuspend the pellet in lysis buffer to initiate cell lysis.

Lysis and Neutralization: Add lysis solution, followed by a neutralizing solution.

Centrifugation: Centrifuge the mixture to separate the supernatant containing plasmid DNA.

Precipitation and Washing: Add isopropanol to precipitate plasmid DNA, followed by washing with ethanol.

Resuspension and Storage: Dry the DNA pellet and resuspend in an appropriate buffer for storage at -20 °C.