LB AGAR (LENNOX) VEGETAL
CAT Nº: 2039
Medium for general purposes, recommended for molecular
genetics studies with E. coli.
FORMULA IN g/l
Soy Peptone
10.0
Yeast extract
5.00
Sodium Chloride
Bacteriological agar
5.00
15.0
Final pH 7.0 ± 0.2 at 25ºC
PREPARATION
Suspend 35.0 grams of medium in one liter of distilled water. Mix well and dissolve by heating with
frequent agitation. Boil for one minute until complete dissolution. Sterilize in autoclave at 121ºC for 15
minutes. Cool to 45- 50º C, mix well and dispense into plates. The prepared medium should be stored at
2-8°C. The color of the prepared medium is amber, slightly opalescent.
The dehydrated medium should be homogeneous, free-flowing and beige in color. If there are any
physical changes, discard the medium.
USES
LB AGAR, LENNOX VEGETAL is as LB Agar, Lennox (Cat. 1083) but changing the animal origin raw
materials to vegetal origin ones. It is a nutritionally rich media developed by Lennox for the growth and
maintenance of pure cultures of recombinant strains of E. coli.
LB agar, Lennox contains ten times the sodium chloride level of Luria Broth Base Miller´s modification
(Cat. 1266) and one half of that found in LB Broth, Miller (Cat.1551). This allows the researcher to select
the optimal salt concentration for a specific strain. If desired, the medium may be aseptically
supplemented with glucose to prepare the complete medium described by Lennox.
Soy peptone provides nitrogen, vitamins, minerals and amino acids essential for growth. Yeast extract is
source of vitamins, particularly the B-group essential for bacterial growth. Sodium chloride supplies
essential electrolytes for transport and osmotic balance. Bacteriological Agar is the is the solidifying agent.
Inoculate and incubate at 35 ± 2ºC for 18-24 hours.
MICROBIOLOGICAL TEST
The following results were obtained in the performance of the medium from type cultures after incubation
at a temperature of 35 ± 2ºC and observed after 18-24 hours.
Microorganisms
Growth
Escherichia coli ATCC 33849
Good
Escherichia coli ATCC 25922
Good
Escherichia coli ATCC 33694
Good
Escherichia coli ATCC 23724
Good
BIBLIOGRAPHY
Ausubel, Brent, Kingston, Moore, Seidman, Smith and Struhl (ed.). 1994. Current protocols in molecular biology, vol. 1.
Green Publishing Associates, Inc., Brooklyn, N.Y.
Mackenzie E.F.N., Taylor E.N. and Gilbert W.E. 1948. Recent experiences in the rapid identification of E. coli, type I. J.
Gen. Microbiol. 2:197-204.
Atlas, R.M., L.C. Parks (1993) Handbook of Microbiological Media. CRC Press, Inc. London
Lennox. (1955). Virology 1:190.
Sambrook, Fritsch and Maniatis. (1989). Molecular cloning: a laboratory manual, 2nd ed. Cold Spring Harbor Laboratory
Press, Cold Spring Harbor, N.Y.
STORAGE
25ºC
Once opened keep powdered medium closed to avoid hydration.
2ºC