[DIYbio] Re: Best storage methods for strains in -20 freezer?

Excellent! Yeah, it would be great if you could keep checking those every once in a while. I have high hopes fro using skim milk as a cryoprotectant as well. - that apparently worked even better than glycerol in reviving cultures that had been defrosted during hurricane Katrina:

Skim milk enhances the preservation of thawed -80 degrees C bacterial stocks.

I would also like to start a little culture collection at Counter Culture Labs. We already have the pigmented bacteria set from Carolina (Micrococcus luteus, Serratia marcescens D1, Sarcina aurantiaca, Rhodococcus rhodochrous), and we want to start experimenting with a bunch of cheese making cultures for the Real Vegan Cheese project. So we'll have plenty of non-E. coli to test storage methods on.

Patrik

On Monday, February 9, 2015 at 10:06:07 PM UTC-8, Koeng wrote:

I've actually experimented on this :D

https://groups.google.com/forum/#!searchin/diybio/4$20months/diybio/u4mxuMNTyMw/VbgwOQA5IUwJ

That was a couple of months ago, so I'll check it again if you want me to see. Essentially, I tried it in -20 at 10%, 20% and 40% glycerol and tried to recover cells from that. They all worked. It seems like storing cells is pretty robust even in these conditions (for 4 months, so far)

I usually just put in 80% glycerol at half the freezing stock (250µl of 80% glycerol for 500µl of cells) and that's worked. To my knowledge, I'm the only one who has done a controlled experiment on this. It'd be great if someone else could put up their research or start their own, I would like this to be reproducible so I can recommend it! I'm working on a standard part distribution for DIYbiologists and it'd be great to have -20 storage protcols

(It also should be noted that I used E coli. S cerevisiae may be different because yeast freeze differently and are more prone to lysis (they just die more in stocks) and B subtilis doesn't even need freezing storage. I store B subtilis on paper) 

-Koeng

On Monday, February 9, 2015 at 8:57:58 PM UTC-8, Patrik D'haeseleer wrote:

Hi all,

The gold standard for long-term storage of strains is glycerol stocks in a -80 freezer. Or even an ultra-low at -150C, or liquid nitrogen at -196C.

However given that most DIYbio labs don't have access to those kinds of resources - what are the best recommendations for storage in a -20C freezer?

50% glycerol? 15% glycerol? 10% skim milk? Stab cultures?

Opinions / best practices wanted!

Patrik