If the genome sample if free of cellular components including DNAse, RNAse, etc. (e.g., extracted with a commercial kit) these conditions will work fine. If you want to be sure, you can turn down the temperature a little bit (e.g., 37ºC), but it will take more time to evaporate the water.

I agree with Pol, 65 is a bit too much. Woud you not be better to ethanol precipitate your DNA ?

SpeedVac is suitable to reduce the volume your samples if purity is fine. If you are limited in the amount of DNA it is the method of choice as there is no loss of the amount of DNA compared to precipitation. But if you are not limited in the amount of DNA I agree with Ian and would go for precipitation as you remove any possible non-DNA contamination in your sample. Of course, such contaminants are enriched when using a SpeedVac and might inhibit your downstream applications.

I haven't tried ethanol precipitation. But it sounds like a good idea! Thanks! I am concentrating plasmid DNA and will use it for transformation. I am wondering if the SpeedVac and SpeedVac conditions has any effect on the my pDNA that would affect my transformation procedure.

Heating is not necessary (befor e and during concentration).  Time is depending on volume and instrument. For 50 µL 15 minutes can be enough. But be careful, you concentrate all ingredients in the solution!

If you will concentrate common plasmid DNA prep, use ethanol precipitation. But it is little tricky the first time. Good luck

I understand well. So my concern is if I concentrate the a 1 ml vol. of DNA to 0.1 ml (10X) at 65 C for 1 h using SpeedVac (I already did concentrate). I am wondering about the stability of the plasmid DNA. How do I confirm if the DNA is not damaged for further steps (i.e. transformation, enzyme digestion etc.)?

I think you can run a agarose gel to see if the DNA band is sharp to confirm the damage of DNA. Good luck.

I did. some DNAs were not clear which could mean they are damaged, while some DNA remained clear bands in agarose gel electrophoresis, which implies intact and stable after SpeedVac. I'm still wondering other effects of SpeedVac... But thanks for your suggestion! :)

I have a similar situation. We have bacteria genomic DNA samples for the following de novo sequencing but the concentration is just not high enough. The DNA amount is limited and doing precipitation will lose too much. We have tried SpeedVac without using heating and it took ~2 hours to get to the volume we needed. But it seems that quite some DNA stick to the micro-tube wall and won't be dissolved? Do we need to use one with cooling function to prevent potential overheating? Thanks.

But it seems that quite some DNA stick to the micro-tube wall and won't be dissolved? Do we need to use one with cooling function to prevent potential overheating? Thanks.

- I believe DNA are pretty stable but you need to check if there are degradation or smears in A.G.E., there is a possibility that your DNA can be damaged. And I would suggest to dissolve them (after SpeedVac) in dH2O not in the same buffer. Because what makes it also very sticky is the salts and contents of the buffer. Let me know what you come up with.

concentration by alcohol precipitation is another option

Hi,

I've tried concentrating with a SpeedVac, but lost a lot of DNA! While I diminished the volume to around 20%, the increase in concentrarion was less than 10%.

Can someone explain this and/or give any hints to avoid that? I know that ethanol precipitation is an option, but I would like to avoid that, if possible, because I'm gonna use this for electroporation and don't want to risk any residual salts...

Speed Vac Ok but my recommendation would be ethanol precipitation (2.5 to 3 times). In this case, you get only purified nucleic acid no other inhibitors. After precipitation perform two times 70% ethanol wash. Dry under laminar and dissolve the pellet in required volume of water. I usually concentrate my DNA inserts and digested vectors this way for cloning

Subha Das could you explain me how to can I do the ethanol precipitation to concentrate my genomic DNA?

Daniel Poveda-Martínez tTake your genomic DNA solution and add either equal volume of isopropanol or 2.5-3 times 100% ethanol. Then add one-tenth volume of 3 M NaOAc (pH 5.5-5.8), mix the solution vigorously for 6-10 times, and then for isopropanol, incubate at room temperature for 30 mins at least. After incubation, centrifuge tubes at 13000 rpm for 10 mins (15 degrees temp). Discard isopropanol and wash the DNA pellet two times with 70% ethanol. Each time centrifuge at the above-mentioned conditions. For ethanol precipitation, you can incubate tubes at -20 degrees overnight and then follow the same procedure. After 70% wash, dry up the pellet either using a speed vac or under laminar air flow. Dissolve DNA pellets either in EB or in mol bio grade water. I usually use water. Store tubes in -20 for future use. If you want more concentrated DNA, dissolve pellets in less water. I hope it helps

Ηi I also meet this problem. We have several fecal bacteria DNA sample to do 16s Sequencing in the future but our concentration cannot reach requirement. We have 50 ul and theoretically if it can be concentrate to 25 ul the concentration will be fine. But how can to know how long we need to achieve this using SpeedVac?

Precipitation is best - 10% volume of 3M NaCl or 3M sodium acetate pH ~5.2 or so. Mix. Then add ~2 vol ice cold 100% ethanol or isopropanol (both work fine). Incubate in freezer/ice for 30 min. Centrifuge 14000 rpm 5 min. Wash pellet with 70% ethanol (0.1 ml should be enough) at least once (twice is better) to desalt. Watch out that the pellet stays put! Some people use glycogen as carrier to help with this process but not always appropriate for all downsteam applications (glycogen works for automated Sanger DNA sequencing). Speedvac the sample or dry in laminar flow cabinet (do not over dry) and then dissolve in desired volume of MilliQ water or 10 mM Tris buffer at pH ~8.1. Voila! There will be some minor yield loss so keep expectations under control.

I use a SpeedVac. It's laborious, but it works when you have almost no DNA. I usually spin at 45C to speed up the evaporation, and I haven't noticed that harming it. Depending on what your starting volume is it can take a long time. I usually dry it down fully and then resuspend in whatever volume I want to to get the target concentration. One caveat is that it's best to have eluted your DNA in water and not a buffer if you use this concentration method. If you've eluted in a buffer you're also concentrating THAT, and I've found nothing at all online talking about how concentrated something like Tris can be before it starts interfering with the reaction.