LB Broth Base (Lennox formulation) is a popular, rich medium used to cultivate bacteria and perform coliphage plaque assays. The original formulation was published in 1951 by Guiseppe Bertani in his study of phage plaque formation and named Lysogeny broth. It is also known as Lennox broth and Luria-Bertani broth.

Widely used LB medium formulations differ in salt concentration:
• Miller: 10 g/L NaCl
• Lennox: 5 g/L NaCl
• Luria: 0.5 g/L NaCl

LB Broth Base is recommended for the general maintenance and growth of E. coli as it allows for fast cell expansion and reach high cell density. Its Lennox formulation has lower levels of salts than Miller and is recommended to use with salt-sensitive antibiotics such as Zeocin, tetracycline, or chloramphenicol.

LB Broth Base formulation and preparation
To prepare 1 L of Lennox-LB media, weigh 20 g of powder, and add distilled water to 1 L. Adjust the pH value to 7.0 with 5 N NaOH and sterilize by autoclaving for 25 minutes at 121°C. Formulation per liter: 10 g SELECT Peptone 140, 5 g SELECT Yeast Extract, and 5 g NaCl. 

Primary applications
• Growth and maintenance of E. coli strains for plasmid purification and/or protein expression
• Resuspension of T. pyriformis cell fractions

Find the media format that fits your needs
We offer other ready-to-use media formulations, such as LB (Lennox), Terrific Broth or S.O.C recovery medium.
Explore other media formats for bacterial growth.