Glycerol stocks at -20?

Colin Rasmussen colin_rasmussen at
Sat Jun 17 15:08:47 EST 1995

vwarwar at (vitor warwar) wrote:
>     Hi all:
>     Does anybody knows of bacteria glycerol stocks could be
>     stored at -20 instead of -70?

Yes they can. We often do this for short-term (months) storage of things 
where we are sorting out which ones we will finally keep. For long-term 
storage (years) -70°C is better. We have found that viability at -20°C 
doesn't seem as good and I would hate to come back to something after a 
few years to find the bugs had died. If this does happen, you can often 
recover the plasmid by taking the seemingly dead glycerol stock, do a 
mini-prep to isolate plasmid and retransform into competent bacteria. We 
have recovered more than one clone in this way.


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