Microbiology - Freezing Bacterial Cultures

Jeff Lawrence

1. Grow 2 mL of overnight culture in selective media.

2. Add 1 mL to culture to a Wheaton Tube containing 100 µL of DMSO; this makes a final concentration of 10% DMSO. Final DMSO of 20% can be used if "slushy" frozens are wanted; these are easier to streak from and are useful for frequently-used stocks.

3. Prepare two independent vials for each strain. Label the cap of the tube with the last two digits of the strain number; this willl aid in choosing strains from the box. Label the side of the tube with the complete strain number, including designation. For example, side may read JGL 4512 and the top may read 12.

4. Place replicate strains in separate freezer boxes.

5. Segregate one box for emergency purposes only. When the emergency vials are used, make an immediate copy.

6. If new boxes are started, log the box into the freezer database and mark the locator sheet.

7. Freeze personal strains into personal strain collections; freeze strains of general interest into the lab collection. Use your judgement here. All strains used in publications must be placed into the lab collection.
Last Update: Thursday, 19-Jun-2014 11:54:33 PDT
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Eric Kofoid eckofoid at ucdavis.edu