An evaluation of chelex-based DNA purification protocols for the typing oflactic acid bacteria

An easy and rapid protocol to extract DNA to be used as template for polyme rase chain reaction (PCR) fingerprinting experiments from cultivable lactic acid bacteria (LAB) is proposed. Different procedures for rapid extraction of DNA by chelex (iminodiacetid acid) ionic resin were compared. Factors a ffecting the quality and reproducibility of PCR fingerprinting profiles wer e also investigated. Two out of three chelex-based protocols allowed to obt ain DNA samples which, after PCR amplification, provided electrophoretic pa tterns comparable with those obtained by classical lysozyme and phenol-chlo roform DNA extraction. A good level of reproducibility and consistency of t he InstaGene procedure was verified. The procedure is fast, practical, and the DNA is of quality similar to that obtained by phenol-chloroform extract ion. Although applied to a little number of LAB strains, chelex-based proto cols are potentially applicable to a vast array of organisms and/or biologi cal materials. (C) 2000 Elsevier Science B.V. All rights reserved.