LB Agar Lennox (Powder)

LB Lennox, a nutritionally rich medium, was developed by Lennox for the growth and maintenance of pure cultures of recombinant strains of E. coli. These strains are generally derived from E. coli K12 which are deficient in B vitamin production. This strain of E. coli has been further modified through specific mutation to create an auxotrophic strain that is not capable of growth on nutritionally deficient media. LB Broth media formulations have been industry standards for the cultivation of Escherichia coli since the 1950’s (1,2,3). These media have been widely used in molecular microbiology applications for the preparation of plasmid DNA and recombinant proteins (4,5). The media are nutrient-rich formulations which provide peptides and peptones, vitamins, and trace elements. The three formulations (Lennox, Miller and Luria) differ in the amount of sodium chloride, thus providing selection of the appropriate osmotic conditions for the particular bacterial strain and desired culture conditions. The low salt formulations, Lennox and Luria, are ideal for cultures requiring salt-sensitive antibiotics.


Component g/liter
Agar 12
Sodium Chloride 5
Tryptone 10
Yeast Extract 5
Total: 32g/Liter
500g makes 15.6 liters


Directions per Liter:

Dissolve 32 grams in 800-900ml of ddH2O stirring gently with heating until completely solubilized. Adjust pH of the medium to the desired level. Add additional water to bring the solution to1L. Dispense into appropriate containers, loosen caps and autoclave for 15 minutes at 121°C (15psi).


Storage and Stability:

Store powdered media at RT. Opened bottles should be capped tightly and kept in a dark, low humidity environment. Prepared media should be kept at 4°C and used within a short period of time.