LB Broth (Miller) is used in molecular genetic studies in a laboratory setting. LB Broth, Miller is not intended for use in the diagnosis of disease or other conditions in humans. LB Broth (Miller) is based on the formula described by Miller. This medium is used for the growth and maintenance of Escherichia coli strains used in molecular microbiology procedures. LB Broth, Miller is a nutritionally rich medium designed for growth of pure cultures of recombinant strains. E. coli is grown to late log phase in LB Medium. Some plasmid vectors replicate to high copy numbers without selective amplification. Some vectors do not replicate so freely and need to be selectively amplified. Chloramphenicol can be added to inhibit host synthesis and prevent replication of the bacterial chromosome. This broth contains a high level of sodium chloride to aid the maintenance of plasmids. If working with temperate bacteriophages, such as lambda, the addition of magnesium sulphate at 2g/l is recommended to promote phage absorption. If required the medium may be aseptically supplemented with glucose after sterilization.