The relation of micro-organisms to carotenoids and vitamin A

ALTHOUGH great advances have been made in our knowledge of the chemistry of the carotenoid pigments little is known concerning the physiology of their production or their r6le in living cells. Ingraham and Baumann [1934] reported that many bacteria were capable of synthesising carotene when grown on simple media in the dark. Since that time a more detailed study has been made of the production of carotene and associated pigments by one of these organisms. M. phlei was selected because it grows well on a variety of synthetic media and because its chemical composition and physiological reactions have received more than ordinary attention.