Most organisms could stay for long periods if stored in glycerol (50% or higher) at temperatures below -70°C

Thanks John, I know but have you tried this with thermophiles? and for fungi (from my experiences) different storage is needed (on skewed agar at 3°C sometimes 14°C depending on fungus....)

Storing in liquid nitrogen may be safer. For fungi, you can try storing in mineral oil at 4°C.

In the case of Phytophthora infestans, it is quite possible to store isolates for several years at a room temperature with a good level of viability.

1) Take glass screw cap tubes (Pyrex #9825); add 1/3-1/2 tea spoon of rye grains. Add about 20 ml of distilled water.

2) Screw caps (but not fully to prevent the breakage of tubes during autoclaving). Pack the rack with tubes into the foil and leave for a night.

3) Autoclave tubes (120oC, 15 min).

4) Work under sterile condition (in a laminar box or cabinet): put a piece of agar with mycelium into a tube and screw a cap tightly.

The racks can be stored at a room temperature, just on shelves. Mycelium grows on a water surface. If the viability of such mycelium during its further use is bad, then you can take one rye grain instead of a piece of mycelium. It also contains fungus, but the viability in this case will be better.

We also store isolates at -80oC under mineral oil... but in this case some additional efforts are necessary to restore isolates up to a satisfactory viability level.

Thanks for your comments, has somebody of you worked (or is working) with thermophilic bacteria or fungi (optimum around 50°C)? I have experiences with mesophiles and/or some cryophiles but unfortunately not with thermophiles (or especially when anaerobic or microaerophilic). ...

If the fungi or bacteria are spore forming , the easiest method to try will the preservation in dry & sterile soil.

Thanks for your replies,

To Andreas: what do you mean with pretty short period?

THX

You might refer to this scientific article for advice on long-term storage of thermophilic bacteria. This article seemed to have some very good information.

Khursheed A. Halik, Preservation of some extremely thermophilic chemolithoautotrophic bacteria by deep-freezing and liquid-drying methods, Journal of Microbiological Methods, Volume 35, Issue 2, March 1999, Pages 177-182, ISSN 0167-7012, http://dx.doi.org/10.1016/S0167-7012(98)00116-X.

(http://www.sciencedirect.com/science/article/pii/S016770129800116X)

I also wonder, might lyophilization (freeze drying) be a possibility? I do not know how thermophilic bacteria specifically would respond but lyophilization is a great long-term method of storage of bacteria, since it does not require you to keep them frozen. Once freeze dried most bacteria can be stored at room temperature. That might be worth exploring.

Tiffany, thanks for your contribution, I appreciate it...;-)

I concur with Tiffany on the fact that most bacteria especially the thermophiles, can be stored at room temperature but must be under sterile condition, so as to avoid cross contaminations. However, it will do well that you maintain a steady temperature, in order to avoid temperature shock, since the cells are in their dormant state.

What is the benefit of liquid nitrogen in fungi storage?