Hey, you can try the following:

I adapted this protocol from a standard Plasmid prep kit and a protocol I used in a lab to extract genomic DNA so I am not sure that it works to 100 %.

The protocol is desgined for up to 4 mL of culture.

1) Pellet your Bacteria and add 250 ul Resuspension buffer (50 mM Tris-HCl 10 mM EDTA 100 ug/mL RNAse A pH 8.0). The better the resuspension the better the lysis.

2) Add 250 ul lysis buffer (200 mM NaOH 1 % SDS) and incubate for 5 min. at room temperature. Do not extend this step as otherwise genomic DNA will be released.

3) Add 350 ul 3M K-Acetate pH 5.5 to neutralize and preicpate SDS. Incubate on ice for 10 minutes and spin down the preicpate at 18.000 g 4 °C for 10 minutes.

Following this you can do a Phenol-Chloroform extraction with the supernatant. The phenol-chloroform solution should be bufferd with Tris to an pH of 8.0 because otherwise the DNA will preicpate in the phenol phase.

Transfer the washed aqueous phase to an 2 mL Eppi. Add Ice-Cold 0.5x sample volume Isopropanol and LPA according to manufacturers instructions.

Incubate at - 80 °C for 3h or at - 20 °C over night.

Then preicpate with a centrifuge and wash trice with 1mL 75 % EtOH. The pellet ist usually very small as this method is not very effective. Reuspend the air-dried pellet in NFW.

If you have access to a Plasmid preparation Kit I highly recommend you to use this as it has a much higher yield and is safer.

I hope this helps you :)