LB Broth, Lennox

Cat. no. CG56BX CulGenex™ LB Broth, Lennox, 1L Polycarbonate Bottle, 1000ml 10 bottles/box


Hardy Diagnostics CulGenex™ LB Broth, Lennox is recommended for maintaining and cultivating recombinant strains of Escherichia coli for molecular analysis.

This product is not intended to be used for the diagnosis of human disease.


LB, or "lysogeny broth", media formulations have been widely used for the cultivation of Escherichia coli since the 1950s, and have become an industry standard in molecular microbiology applications for the preparation of plasmid DNA and recombinant strains of E. coli . (3,5-8) In general, typical wild type strains of E. coli are capable of growth in minimal media. However, researchers have exploited auxotrophic mutations in strains used for molecular manipulations, making them dependent upon specific growth factors; one strain in particular, E. coli K-12, is deficient in vitamin B production and is incapable of growth in nutritionally deficient media.

The original recipe for LB medium was formulated by Giuseppe Bertani and published in 1951. (3) LB media have since been adapted by Miller, Lennox and Luria to contain differing concentrations of sodium chloride in order to provide the appropriate osmotic conditions for the strain of interest. LB Broth, Lennox contains half the sodium chloride concentration of LB Broth, Miller and ten times that found in Luria Broth, Miller. (3,5-8) Low salt formulations, such as those adapted by Lennox and Luria, are ideal for salt sensitive applications.

LB Broth, Lennox was adapted by E.S. Lennox in the mid 1950s and is a nutritionally rich medium designed to contain certain trace elements for the growth and maintenance of pure recombinant strains. CulGenex™ LB Broth, Lennox is based on this formulation and contains tryptone and yeast extract for amino acids, vitamins and essential minerals. The moderate amount of sodium chloride provides sodium ions for transport and helps maintain osmotic balance. If desired, glucose can be aseptically added during preparation to complete the medium described in full by Lennox. (5)


Ingredients per liter of deionized water:
Tryptone 10.0gm
Sodium Chloride 5.0gm
Yeast Extract 5.0gm

Final pH 7.0 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.


Storage: Upon receipt store at 2-30ºC. away from direct light. Product should not be used if there are any signs of deterioration, discoloration, contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect from light, excessive heat, moisture, and freezing.



Consult listed references for recommended test procedures. (2,5,8,9)


Growth in broth is indicated by turbidity or cloudiness of the medium.



Hardy Diagnostics tests each lot of commercially manufactured media using appropriate quality control microorganisms and quality specifications as outlined on the Certificates of Analysis (CofA).

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Escherichia coli
ATCC ® 25922
A 18-24hr 35°C Aerobic Growth


Physical Appearance

CulGenex™ LB Broth, Lennox prepared media should appear should clear, and light amber in color.


1. Anderson, N.L., et al. 2005. Cumitech 3B; Quality Systems in the Clinical Microbiology Laboratory, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.

2. Ausubel, F.M., R. Brent, R.E. Kingston, D.D. Moore, J.G. Seidman, J.A. Smith, and K. Struhl. 1994. Current Protocols in Molecular Biology . Vol. 1. Current Protocols, New York, N.Y.

3. Bertani, G. 1951. Studies on Lysogenesis. I. The Mode of Phage Liberation by Lysogenic Escherichia coli . J. Bacteriol. ; 62:293-300.

4. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.

5. Lennox, E.S. 1955. Transduction of Linked Genetic Characteristics of the Host by Bacteriophage P1. Virology ; 1:190.

6. Luria, S.E., and J.W. Burrous. 1957. Hybridization Between Escherichia coli and Shigella . J. Bacteriol. ; 74:461-476.

7. Luria, S.E., J.N. Adams, and R.C. Ting. 1960. Transduction of Lactose-Utilizing Ability Among Strain of E. coli and S. dysenteriae and the Properties of the Transducing Phage Particles. Virology ; 12:348-390.

8. Miller, J.H. 1972. Experiments in Molecular Genetics . Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.

9. Sambrook and Russell. 2001. Molecular Cloning: A Laboratory Manual, 3rd ed. Cold Spring Harbor Laboratory. Cold Spring Harbor, N.Y.

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