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From 2011.igem.org

Luria-Bertani Media (LB Broth)

 Tryptone        1.0%     (a proteolytic digest of milk proteins)
 Yeast Extract   0.5%     (a source of vitamins and nutrients)
 NaCl            1.0%     (table salt - guess those little E. coli's like tasty food just like people do)

Note: One ml of water weighs 1 gram (under ideal conditions -- for us it's close enough). It is by weight that we measure the dry ingredients.

So, when you wish to have x% of some ingredient in your final solution, the calculation looks like this:

For each 100 ml final solution, use x grams of the ingredient.

So, if we wish to make 1 liter (1000 ml) of LB Broth, we measure the following amounts of the dry ingredients:

10 gr Tryptone 
 5 gr Yeast Extract
 1 gr NaCl

Add some of the water and adjust the pH using 10 N NaOH (about 0.1 ml)

Then add enough water to have a final volume of 1 liter. Use a large flask with measuring lines - the volume will be close enough.

Next use a funnel to aliquot about 200-250 ml into clean bottles that will serve as storage bottles, and autoclave on liquids cycle for 20 minutes at 15 psi (121 degress Centigrade is normal).

If you are going to add antibiotic, wait until the broth has cooled enough that you can handle the bottles. To each 1 ml broth, add 1 ul of 50 mg/ml ampicillin. (So, for 200 ml bottle, add 200 ul ampicillin).

Put into the refridgerator for storage.