Description: Recommended medium for the test of Escherichia coli in molecular genetics studies. LB Broth Lennox is nutritionally rich medium developed by Lennox for the growth and maintenance of pure culture of recombinant strains of E. coli. In the formula, Tryptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is source of vitamins, particularly the B-group. Sodium chloride supplies essential electrolytes for transport and osmotic balance.
Directions for use: Suspend 20 grams of the medium in 1 L distilled water. Mix well and dissolve by heating and stirring. Boil for one minute until complete dissolution. Dispense into appropriate flasks and sterilize in autoclave at 121°C for 15 minutes. The prepared medium should be stored at 2-8°C. The color of the prepared medium is clear amber.
Composition:
-Tryptone (pancreatic digest of casein) 10 g/L
– Sodium Chloride 5 g/L
– Yeast Extract 5 g/L
(Final pH 7.0± 0.2 at 25 ºC)
Microbial Test: The following results were obtained in the performance of the medium from type cultures after incubation at a temperature of 35 ± 2°C and observed after 18-24 hours:
Microorganisms                                         Growth
Escherichia coli ATCC 23724 Â Â Â Â Â Â Â Â Â Â Â Good
Escherichia coli ATCC 47014 Â Â Â Â Â Â Â Â Â Â Â Good
Escherichia coli ATCC 33694 Â Â Â Â Â Â Â Â Â Â Â Good
Escherichia coli ATCC 33849 Â Â Â Â Â Â Â Â Â Â Â Good
Escherichia coli ATCC 39403Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Good
Soluble in: water
Storage: Store at 2-25ºC. Once opened, keep the powdered medium closed to avoid hydration. Protect form light and moist
