Luria Agar (Miller's Modification)

Luria Agar (Miller’s LB Agar) is a dehydrated powder for the preparation of nutritionally rich solid medium (plates) for the growth and maintenance of recombinant strains of E. coli in molecular biology studies.

This rich growth medium contains all the nutritional requirements for E. coli. Tryptone and Yeast Extract are the sources for carbon, nitrogen, vitamins, minerals, and amino acids essential for growth, while sodium chloride supplies essential electrolytes for transport and osmotic balance. For faster growth, the medium can be supplemented with glucose (0.1%) or glycerol (0.4%). Many supplements, including antibiotics, are heat-sensitive and cannot be autoclaved. These should be filter-sterilized and added to the medium after it has cooled down and prior to solidification.

Formulation (g/L)

• Tryptone: 10.00
• Yeast Extract: 5.00
• NaCl: 0.50
• Bacteriological Agar: 15.00
• Final pH (25°C): 7.0 ± 0.2

Preparation

Add 30.5g of the dehydrated medium to one liter of distilled water. Mix well and dissolve by heating with regular agitation. Boil for 1 minute in order to dissolve completely. Dispense in appropriate containers and sterilize by autoclaving at 121ºC for 15 to 20 minutes. Cool to 45-50ºC and dispense into plates. Plates should be stored at 8-15ºC.