LB Broth

Cat. no. CG10BX LB Broth, 125ml Polycarbonate Bottle, 100ml 6 bottles/box
Cat. no. CG50BX LB Broth, 500ml Polycarbonate Bottle, 500ml 10 bottles/box
Cat. no. CG51BX LB Broth, 1L Polycarbonate Bottle, 1000ml 10 bottles/box


Hardy Diagnostics CulGenex™ LB Broth is used for the maintenance and propagation of Escherichia coli used in molecular biology procedures.

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 the growth of recombinant strains.(3,5-8) LB medium was originally formulated by Giuseppe Bertani and published in 1951 and has since been modified by Miller, Lennox and Luria: the formulations differ in the concentration of sodium chloride, which provides for greater selectivity.(3) LB Broth, Miller medium contains 10gm of sodium chloride; LB Broth, Lennox contains 5gm of sodium chloride; and Luria Broth, Miller contains 0.5gm of sodium chloride.(3,5-8) Low salt formulations, such as those by Lennox and Luria, are ideal for salt-sensitive applications.

Adapted by J.H. Miller, LB Broth is a nutritionally rich medium designed for the growth and culture of pure recombinant strains used in genomic testing.(8) Hardy Diagnostics CulGenex™ LB Broth media formulations are based on the original recipe by Miller and contain casein peptone and yeast extract for amino acids, vitamins and essential minerals. Sodium chloride provides sodium ions for transport and helps maintain osmotic balance.


Ingredients per liter of deionized water:*

Tryptone 10.0gm
Sodium Chloride 10.0gm
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. Media 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.



Refer to appropriate references for recommended test procedures.(2,3,5-9)


Growth should be evident by the appearance of turbidity in the medium.



Standard microbiological supplies and equipment such as loops, swabs, applicator sticks, other culture media, incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.


The following organisms are routinely used for testing at Hardy Diagnostics:

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 should appear clear to slightly opalescent, and light amber in color.


1. Anderson, N.L., et al. 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: 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.

ATCC is a registered trademark of the American Type Culture Collection.