LB Broth (Lennox), also known as LB (Luria-Bertani) Broth, is a bacterial culture medium with a rich nutrient composition. Commonly used in microbiology and molecular biology, this media type supports a variety of applications that involve the growth of Escherichia coli (E. coli), and other similar bacterial strains. Consisting of peptones, yeast extract, and low salt content, this growth medium supplies bacterial colonies with the resources they need to grow and reproduce.