Incubate the tubes at 65 degrees C for 5-7 min. Add 300 microliters of 7.5 M ammonium acetate, invert each tube to mix the contents and incubate on ice for 10 min. Spin for 3-5 min and pipette 700 microliters of the supernatant into a new tube. Add 500 microliters of isopropanol to each sample, invert the tubes to mix the contents and incubate on ice for 10 min. Spin for 3 min, discard the supernatant and invert the tubes on a paper towel to wick away the excess liquid.
Ethanol precipitate the DNA and resuspend to a convenient concentration.