L-Broth

Luria Broth Base (Miller's Modification)

Luria Broth Base or L-Broth is based upon the Luria Broth formulation as originally developed by Miller for cultivation and maintenance of E. coli cells in molecular biology.

L-Broth is a nutritionally rich medium originally developed for growth and maintenance of recombinant E. coli strains. E. coli is grown to late log phase in LB Broth. These strains are generally derived from E. coli K12 which are deficient in B vitamin production. K12 has been ultimately modified by specific mutation into an auxothropic strain not capable of growth on nutritionally deficient medium. All nutritional requirements of E. coli strains are provided by LB Broth. Peptides and amino acids are abundantly present in Tryptone. Yeast extract is a rich source of amino acids, vitamins, nucleotides and carbohydrates. These nutritional elements in LB media, which otherwise the cell would have to synthesize, support a luxurious growth of E. coli cells.

Sodium ions for transport and osmotic balance are provided by Sodium chloride.

The concentration of NaCl in L-Broth is low compared to both LB Miller and LB Lennox formulations, respectively 10% and 5% of the NaCl concentration is present in both formulations.

These variations in Sodium chloride content make it possible to select the optimal salt concentration for a specific strain.

Miller, J.H., Experiments in molecular genetics, Cold Spring harbour Laboratory, Cold Spring harbour, New York, (1972).

Lennox, E.S., Transuction of linked genetic characters of the host by bacteripphage P1, 1, 190-206, (1955). Sambrook, J,., E. F. Fritsch, and T. Maniatis, 1989, Molecular cloning: a laboratory manual, 2nd edition ed., Cold Spring Harbour laboratory, Cold Spring Harbour, N.Y.

Suspend 15.5 gram powdered medium in 1 litre distilled water

Store dry at room temperature