LB: Luria-Bertani Medium (Miller)

Rich media used for routine culture of E. coli and other bacteria at high cell densities.

Add dH₂O to final volume. Autoclave. If mixing up large batches and aliquoting, be sure to add exact volumes to final media bottles so that they will be ready for addition of antibiotic to known concentrations.

This recipe is from Miller JH. (1992) A Short Course in Bacterial Genetics. CSHL Press. Handbook Unit 25.5.

Note: Be aware that (1) there are several other formulations that may be called LB but vary the amount of NaCl. Using the wrong one can cause large changes in growth. (2) LB was originally supposed to stand for "Lysogeny Broth" and you may also see it called "Luria Broth" (more about this).

Expected results: E. coli strains grow to 5×10⁹ cells/ml final density in LB.

Variant: 0.1×LB is made with 1 g Tryptone, 0.5 g Yeast Extract, and 10 g NaCl per liter. (It is 0.1× in the nutrients, but not the salt!)