prerservation of pleurotus

[Michael Clark]

Cynthia Wang wrote:

>I am trying to preserve the mycelia of Pleurotus ostreatus.  I tried to
>freeze the culture broth/suspension but the revival rate was very low
>and it takes 3 weeks to recover the culture from frozen to an agar
>culture.  Any suggestions?

Did you use any cryoprotectant?  The standard for yeast work is 10%
glycerol.  You could also try 10% DMSO, which is what we use for
freezing mammalian cells.  These agents dramatically improve survival
of frozen microorganisms. Also, what temperature are you freezing at? 
The colder the better.  -70C is the standard for long term
cryopreservation of bacteria and yeast.  Survival is reduced at -20C. 
BTW: slow freezing works better than flash freezing (i.e. immersion
into liquid N2).

Or it may be that Pleurotus just doesn't freeze well. I've successfully
frozen at -70C, with excellent recovery, both Coprinus comatus and
Stropharia ruguloso-annuata in 10% glycerol.  But I'm still working to
freeze morel mycelium (any suggestions would be helpful, hint hint to
anyone in the know!)

--Michael Clark
--University of Iowa
--Molecular Biology Program