Glycerol Stock

E. coli can be frozen for indefinite long-term storage at -80C in the presence of 15% glycerol.

1. StreakForIsolation and grow a small overnight culture from a single colony
   
2. add 300 μl of sterile 50% glycerol to 700 μl of the overnight culture
   
3. mix well by pipetting up and down and store at -80C
   

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Comments

• Filter sterilize the 50% glycerol (by volume with water) solution and store at room temperature.