LB Media and Plates

Kay Finn
last updated: May 13, 2003

LB Media
3 capsules LB-Medium (BIO 101, Inc)/ 750 ml H20 in 1 liter Schott bottle (cap loosened).
Autoclave 30 minutes liquid cycle, standing on the rack with plenty of air around the flask.
Cool, tighten cap on bottle, store room temperature.

LB Plates
4 capsules / liter of LB-Medium (BIO 101, Inc) in 2 liter flask with 1 large stir bar.
Add 10 g Agar, granulated (Difco #214530).
Autoclave for 30 minutes liquid cycle, standing on the rack with plenty of air around the flask.
Place on stir/heat plate. Stir and set at 40 degrees.
When cool enough to handle, get ready to pour.

Clean a bench area with lysol or alcohol.
Have a bunsen burner ready for flaming neck of flask.
Set out 2 packages of plates stacked only 2 or 3 high.
Pour close to edge of bench and near burner, flaming frequently.
Try not to slosh the liquid up to the lids.
Let set up at least 1 hour, longer if possible.
Store in cold room, mark date on package.

LB-Amp Plates
Ampicillin freezer stock = 50 mg/ml (filter sterilized in >1ml aliquots)

Similar to LB plates as above, only make 1 package of plates:
- 2 capsules / 500 ml volume in 2 L flask. Add 5 g Agar, granulated. Add 1 stir bar.
- 30 minutes on liquid cycle.

Stir on stir/heat plate set at 40 degrees. When media cool enough to pour:
Add 1 ml of amp stock / 500 ml media (100 mg/liter) and mix well before pouring.
Mark plates with a double line down the stack when repackaging for storage.
Good for 1 month, if kept cold and dark.