A general method for plasmid isolation in lactobacilli

A simple procedure for rapid isolation and detection of plasmid DNA fromLactobacillus species is described. Using an alkaline-detergent lysis method, plasmid DNA was released and characterized from cells treated with either mutanolysin or lysozyme for 1 h at 0°C. Treatment of cells with either enzyme at 37°C for 1h was detrimental to plasmid isolation and charaterization in someLactobacillus species. The procedure was effective with small volumes of cells and allowed rapid characterization of plasmid DNA inLactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus helveticus, andLactobacillus bulgaricus strains.