Freezing Bacterial Cells

Eric C. Kofoid kofoid at
Thu Aug 6 12:37:13 EST 1992

>From: DMEIER at
>Newsgroups: bionet.molbio.methds-reagnts
>Subject: Freezing Bacterial Cells
>Message-ID: <01GN9B91X4EU8Y54ON at>
>Date: 6 Aug 92 16:42:49 GMT
>Sender: daemon at
>Distribution: bionet
>Organization: Medical College of Wisconsin (Milwaukee, WI)
>Lines: 7
>Hi all,
>  I freeze bacteria in a 3.5% DMSO solution and have had good luck, but
>anyone know if snap freezing bacteria on dry ice is preferable to
sticking them 
>in a - 80 C freezer and letting them slowly freeze?
>  I'm looking forward to your comments.
>Dan Meier

We routinely store our strains in 2.5% DMSO. After adding the reagent in
microliters to 2 ml of culture, we place it in a rack at -70 degrees with 
no intermediate quick-freeze step. Viability is excellent. We have nearly 
10,000 strains archived in this fashion. Some are over 20 years old, and 
can still be recovered without difficulty. 

|  Eric Kofoid                         Parkinson laboratory        |
|                                      Dept.Biology, U. of Utah    |
|  "Being certain of the conclusion assists in finding the proof"  |
|                                      Galileo, 17th century       |

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