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Recycle Those DNA Extraction Columns

Posted in: DNA / RNA Manipulation and Analysis
Recycle Those DNA Extraction Columns

You know those ridiculously priced and throw-away DNA mini, midi and maxi-prep columns? Well the good news is that you can actually re-use them if you are reasonably careful at regenerating them, with this simple and cheap method described in detail by Nagadenahalli B. Siddappa in Biotechniques in 2007.

Apparently these columns can be reused up to 20 times… perhaps more a guesstimate than a real number, but hey, who’s complaining?

Essentially the columns are treated with 1M HCl overnight, rinsed extensively with dH2O and then re-equilibrated with buffer from the kit you use (e.g. Qiagen QBT). If you are worried about finishing the buffers in the kits, look in the back of the manual, there are often simple recipes about how to remake them.

The authors allay concerns about plasmid carryover contamination by assaying for plasmid using RT-PCR and transfection assays which all showed zero carryover between recycled uses of the columns. In fact they showed that the plasmid DNA had been chemically sheared into low molecular weight fragments and could not be used as a template.

They also stated that prolonged exposure to 1M HCl (1 month) did nothing to the binding capacity of the columns, so even if you forget about it, there is no need to stress.

Our lab has modified the protocol to include passing warm water through the treated columns when regenerating to ensure that all DNA and any other contaminants are removed. Also pre-warming the elution buffer to 42oC or thereabouts seems to increase the elution of any plasmid DNA bound to the column, although what extra compounds it releases is unknown but probably negligible.

It may be our imagination, but we have often gotten higher yields of plasmid DNA from a treated reused column, than a new one.

Go ahead, stretch those budgets further.

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  1. Bill on April 15, 2010 at 3:02 pm

    Can I use vacuum manifold instead of gravity flow during extraction?

  2. Steve on November 18, 2009 at 3:51 pm

    Thanks for the detailed reply. I am trying out the silica method on some qiagen miniprep spin columns and will see how it goes. we also have peqlab miniprep tubes which I will look at. I will post my results…

  3. Jode on November 17, 2009 at 5:22 am

    I’ve been using this method for a while, and I’ve tried it on both the gravity-based DEAE columns (like the Maxi Prep) and the silica membrane based spin columns from Qiagen. There are Mini-Prep scale columns for both, and I have the feeling from some of the posts that they are being confused.

    The DEAE based columns (the DNA elutes in high salt and must be precipitated afterwards) work great with this system. Like Liam, I’ve found that the capacity of the columns actually increases after regeneration, and I’ve been re-using the same columns for well over 20 times with no detectable degradation of the columns.

    Here is the protocol that I worked out by sampling the flow-through of the column washes onto litmus paper. I would encourage anyone who is doing this to test the protocol with litmus paper for yourself the first time you try it. When I refer to column volume here, I don’t mean the bed volume of the resin, but the actual maximum volume that the plastic column will hold (ex. 30 ml for a Q500 (Maxi), 2.75 ml for a Q20 (Mini)).
    – Drain the 1M HCl stored in the column
    – Wash with 1 column volume of Sterile, Nano-Pure (18M?) Water (NPW)
    – Wash again with 1 column volume of NPW
    – Wash with 1 column volume of DNA Elution Buffer (Buffer QF)
    – Wash with ½ column volume of NPW
    – Equilibrate with 1 column volume of Equilibration Buffer (Buffer QBT)
    Perform the DNA prep according to protocol.
    – After eluting the DNA, wash the column with an additional ½ column volume of Elution Buffer
    – Wash the column twice with 1 column volume of NPW
    – Wash the column with ½ column volume of 1M HCl
    – Cap the column with a luer cap, add ½ column volume 1M HCl, and parafilm the top.

    Occasionally, when I pull a column out of storage I find that there are gas bubbles in the resin. When I see this, I wash the column once with NPW to get rid of the majority of the acid, then cap the bottom securely and fill the column halfway full with NPW, then insert a rubber stopper with a single hole in the top of the column and apply a vacuum with my aspirator. I rap the column gently against the edge of the counter until air stops bubbling out of the resin, then I release the vacuum, un-stopper the top, uncap the bottom, and allow the column to drain. I then continue the protocol outlined above with the second column volume of NPW. I’ve found I can do this with Q100 on up, but when I tried it with a Q20 it just sucked air through the capped bottom. (I’m currently experimenting with ethanol washes to eliminate the gas bubbles instead of vacuum treatment.)

    I found that I can regenerate the silica based spin columns as well, but they aren’t as robust to repeated uses. I stored the columns with 500ul of 1M HCl in them, with the top capped with a 1.5ml Eppendorf Tube cap. This wasn’t perfect, and sometimes the columns dried out, but this didn’t seem to negatively affect the column. To use the columns I would do the following:
    – Spin the columns at max g for 30 seconds to drain the acid
    – Wash with 800ul of 100mM Tris (pH 8.0) twice
    Perform the miniprep according to protocol, and elute the DNA
    – Return the column to the 2ml wash collection tube and wash with 800ul TE
    – Wash the column with 800ul of NPW
    – Wash the column with 200ul 1M HCl
    – Add 500ul to the column and cap the top, store in the 2ml collection tube

    I found that the columns could be re-used several times without any loss of DNA binding capacity, but eventually the membrane in the bottom of the spin column would start to detach from the sides and pieces of it would come off during the wash steps. Since this made me nervous, and I didn’t want to try to re-invent the Qiagen buffers N3, PB and QG (all of which are proprietary), I decided to discontinue regenerating the spin columns.

    • Alex on August 8, 2016 at 11:37 am


      Thanks for the clarification. I have some questions related with the silica-based spin columns. You mention a step: „Return the column to the 2ml wash collection tube and wash with 800ul TE“. What does TE mean? After how many uses did the membrane start to come off from the spin column?

      Also, since , I have a low copy plasmid to be isolated, I need lot of material. For this purpose I would like to use the same column twice for the same bacterial suspension, since I think it is a better idea to use the column twice than to pellet lets say 10 ml bacterial suspension in one round. An I have only a miniprep. Do I need to wash the column in between? If yes, can I use the same washing step as for the repeated use of the columns described by you? Since I do not really want to spend the buffers from the kit for this purpose.

      Thanks a lot,


  4. Steve on November 16, 2009 at 1:19 pm

    did anybody come up with a definitive protocol for this, including the re-equilibriating in buffer? Is washing 5 times in dH2O sufficient to reactivate the martix or does it require washing in buffer (e.g buffer p1 or elution buffer from qiagen kit for example)?

    Thanks for any assistance.

  5. Liam on February 20, 2009 at 7:09 am

    I usually was them 3 or 4 times in distilled water to help get rid of salts, then pull through half a column of HCl (1M) and place the column in a 5L beaker, so it is submersed. They soak overnight, then get 5 washes the next day, allowed to dry, and reused.

    Most miniprep kits do give good enough DNA for sequencing, however I have used the recycled columns, and good old 1 2 3 and have had no problems. It is mostly determined by the hands of the user.

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