Bacterial cells were harvested through centrifugation in the late
exponential phase, and resuspended in 567 mL TE buffer (10 mM
Tris, 1 mM EDTA; pH 8.0). 3 mL proteinase k (2% w/v) and 30 mL of
sodium dodecyl sulfate (10% wt/vol) was added to cell suspension,
then mixed up and incubated at 37 C for 60 min 100 mL sodium
chloride (5 M) and 80 mL CTAB/NaCl (10% w/v CTAB, 0.7MNaCl)was
added to cell suspension, and incubated at 65 C in a water bath for
10 min.