LB Medium and Agar Plate Recipe (also L-Broth or Luria Bertani)
0.5% Yeast Extract
1.0% Sodium Chloride (NaCl)
Protocol for LB liquid medium:
- For 1 liter, dissolve 10 g Tryptone, 5 g yeast extract, and 10 g NaCl in 950 ml
- Adjust the pH of the solution to 7.0 with NaOH and bring the volume up to 1 liter.
It may not be necessary to adjust pH every time, since pH of LB naturally close to pH 7.0. This might be affected by your yeast extract.
- Autoclave on liquid cycle for 20 minutes at 15 psi. Allow solution to cool to
55 C and add antibiotic if needed.
- Store at room temperature or at 4°C if antibiotic is added.
Protocol for LB agar plates:
- Prepare LB medium as above, but add 15 g/L agar before autoclaving.
- Autoclave on liquid cycle for 20 minutes at 15 psi.
- After autoclaving, cool to ~55 C, add antibiotic, and pour into 10 cm plates.
- Let harden, then invert and store at +4 C, in the dark.
Good luck with your cloning and other experiments!