Unité Biologie Moléculaire du Gène chez les Extrémophiles, Institut Pasteur, 25, rue du Docteur Roux, F-75724 Paris Cedex 15, France. sezonov@pasteur.fr
Luria-Bertani broth supports Escherichia coli growth to an optical density at 600 nm (OD(600)) of 7. Surprisingly, however, steady-state growth ceases at an OD(600) of 0.3, when the growth rate slows down and cell mass decreases. Growth stops for lack of a utilizable carbon source. The carbon sources for E. coli in Luria-Bertani broth are catabolizable amino acids, not sugars.