Hello Leonhard, 

It depends on what you plan to do with the pellet once you're done with the storage. If your goal is to just lyse the cells and extract the proteins then I would suggestion keeping the pellet in the -80. It helps preserve them and I feel that it helps with the lysis. I always keep my pellets in the -80 for short term storage during my protein expressions. 

Cheers, 

Ben 

Hi there,

If the cell pellet is going to be lysed then -20°C is OK as freezing will help the lysis. I don't think -80C°C would make any difference in this case. Avoid +4°C as cells are not totally arrested at this temperature.

Hi there....

For me, storing the bacterial cell pellets in -20 degree celsius for weeks works well without compromising the protein yield and quality. Don't store them at 4 degree at all for more than few mins. 

Thanks aot for your answers! And sorry I forgot to specify the purpose of the experiment. Actually, I don't want to lyse the bacteria, but employ them as healthy as possible to monitor adherence. In this case, is it ok to keep them at -20/-80 for a few days?

If you want to keep them alive you have to freeze them with 50 % glycerol or DMSO at -80°C or leave them at 4°C in medium.

@Marianne: So it is possible to just take the falcon with the overnight culture and put in into the fridge for a few days? That's simple!

Hi Leonhard,

For storing in -80 you can do the following what I use to do in my lab to store my organisms, it is working for last four years.

Culture your organism in 50 microlitre of LB Broth in a vial, incubate over night (up to 12 hrs preferred), next morning add 35 micro litre of LB broth and 15 micro litre of glycerol. it works nicely for me.

For storing in +4, i do a stab culture making a media with 10% peptone, 5% Sodium chloride and 0.8% Agar. I can store them over years.

Thanks and best. 

I think this should work, we routinely leave 1 ml of overnight cultures in the fridge, till we have minipreps and DNA check finished and use them for further cultures. Do you have any antibiotics in the medium?

Dear friends,

I have a question in this around.

To store E.coli at -20 or - 80 C, is it required to flash-freeze the sample in liquid nitrogen before storing?

Thanks