How to store bacteria and phage

The Phage Cookbook by Dominik Refardt

How to store bacteria and phages

Glycerol stocks of bacteria

• • Glycerol/NaOH: 150 ml water, 4.25 g NaCl, add Glycerol to 500 mL, autoclave, aliquot in 50 mL tubes and store at -20 °C

  • Mix 5 parts bacterial culture with 4 parts Glycerol/NaOH

  • Mix by pipetting up and down and store at -80 °C

  • Or: Prepare 50% glycerol, autoclave. Mix 3:7 with bacterial culture (= 15% glycerol).

Storing the glycerol in aliquots in the freezer prevents contamination and ensures peace of mind when using it in irregular intervals.

Phage stocks

Phage lysates (in SMG) can be kept at 4 °C. Add a drop of chloroform to prevent fungal or bacterial growth. The chloroform has to be replaced from time to time because it evaporates.

If storage at -80 °C is required, use the recipes below.

• • Add 35 µL DMSO to a cryotube

  • Dilute 50 µL phage lysate in 500 µL LB and add

  • Mix by pipetting up and down and store at -80 °C

  • Alternatively, phage lysates can be frozen in 50% glycerol (not 15%, like it is used with bacteria!)