The bacterial cell mass was harvested in
pellet by centrifugation at 10,000 rpm for 1 min. The cell mass was lyzed by
suspending in 10 mM Tris EDTA buffer (TE) containing 20 mg ml−1 lysozyme, followed
by incubation at RT for 10 min. The cellular proteins in the lysate were removed by
three extractions with phenol:chloroform (1:1 v/v) followed by chloroform:isoamyl
alcohol (25:1 v/v).