'Iron Transport' Compounds as Growth Stimulators for Microbacterium sp.

Abstract
An organism, resembling Microbacterium lacticum, was found to be stimulated by liver or yeast extract in a medium composed of glucose, amino acids, vitamins, adenine, guanine, uracil, ammonium formate, and mineral salts. These complex materials could be replaced by comparable concentrations of porphyrin-containing compounds and by extremely low concentrations of ferri-chrome, coprogen, or terregens factor, which are thought to act as intra-cellular "iron transport factors".