Rapid mini-prep isolation of high-quality plasmid DNA from Lactococcus and Lactobacillus spp.

A simple, rapid plasmid mini-prep procedure for lactococci and lactobacilli which gives high yields and can be performed on overnight broth cultures is presented. Large plasmids were isolated from both lactococci and lactobacilli, including a 70-kb plasmid from Lactobacillus acidophilus C7. The purity of the resulting plasmid DNA makes it suitable for subsequent molecular manipulations. The convenience of the technique makes this rapid mini-prep procedure suitable for routine plasmid isolation from lactic acid bacteria.