Minipreparation of plasmid DNA is a rapid, small-scale isolation of plasmid DNA from bacteria. Commonly used miniprep methods include alkaline lysis and spin-column based kits.  It is based on the alkaline lysis method. The extracted plasmid DNA resulting from performing a miniprep is itself often called a "miniprep".
Minipreps are used in the process of molecular cloning to analyze bacterial clones. A typical plasmid DNA yield of a miniprep is 5 to 50 µg depending on the cell strain.
Miniprep of a large number of plasmids can also be done conveniently on filter paper by lysing the cell and eluting the plasmid on to filter paper.