Several companies produce miniprep kits with their own buffers and solutions, but they all generally involve the same steps: cell lysis, neutralization, multiple column washes, and elution. Here are some tips for increasing DNA recovery

• Instead of using the amount of ON culture that the kit calls for, use 1.5 mL of culture, pellet, then add another 1.5 mL of culture and pellet again. If the kit comes with a resuspension solution, vortex to resuspend. If the kit does not include a resuspension solution, resuspend in 1X TE buffer.
• Add a dry spin step after the last column wash step to remove ethanol residue.
• Elute with nuclease free water instead of elution buffer. The two are generally interchangeable in many protocols, and we found from experience that water actually gave better yields. Also, your DNA is now suitable for PCR, because DNA eluted with elution buffer should not be used for PCR reactions.
• Let column stand for 10 minutes at room temperature before centrifuging to elute.

We used the GenCatch Plasmid DNA Miniprep Kit from Epoch Life Science

1. Add 1.5 mL ON culture to microcentrifuge tube. Remember to pipet ON culture up and down to mix before adding. Pellet the cells by centrifuging for 1-2 minutes at maximum speed. Decant the supernatant, then add another 1.5 mL ON culture and repeat centrifugation. Decant the supernatant and remove all medium residue by pipet.
2. Completely resuspend the cell pellet in 200 uL of MX1 buffer by vortexing until there are no visible clumps.
3. Add 250 uL MX2 buffer and gently invert 4-6 times to lyse the cells. Incubate at room temperature for 1-5 minutes. Do not vortex - this could cause genomic DNA contamination.
4. Add 350 uL MX3 buffer to neutralize the lysate and gently mix solution immediately. Centrifuge for 10 minutes.
5. Transfer supernatant (about 800 mL) to a spin column. Centrifuge 30-60 seconds at 5000 PM. Discard flow-through.
6. Wash column with 500 uL WN buffer by centrifuging for 30-60 seconds at 9000 RPM. Discard flow-through.
7. Wash column with 700 uL WS buffer by centrifuging for 30 seconds at 9000 RPM. Discard flow-through.
8. Centrifuge the column at 13000 RPM for another two minutes to remove residual ethanol.
9. Place the column into a new labeled microcentrifuge tube. Add 50 uL of nuclease free water. Be sure the water is suspended onto the center of the membrane and is completely absorbed.
10. Let column stand at room temperature for 10 minutes to increase recovery yield. Centrifuge for 30 seconds at 13000 RPM to elute.
11. Nanodrop and write DNA concentration to microcentrifuge tubes before storing.