Observations on the Growth of Escherichia Coli in Media Containing Amino Acids as the Sole Source of Nitrogen

The deaminase activity of Escherichia coli for various amino acids has been investigated by many workers, but cells were almost invariably grown in com-plex media. Lodge and Hinshelwood (1943) have described the growth of Aero-bacter aerogenes in media containing various amino acids, but the findings were not related to any biochemical aspects of amino acid metabolism except that the production of toxic products was postulated in unaerated cultures. The present paper describes a study of the growth constants and characteristics of E. coli in glucose-phosphate medium containing single amino acids as the sole nitrogen source. Such growth is a measure of the production of requisite de-amninase systems which make available the nitrogen required for cell division, and, therefore, this method of growth is capable of application to the investiga-tion of various other aspects of the organism's amino acid metabolism. Appli-cations of the method are embodied in this communication, and they afford further examples of the value, which has been stressed by Monod (1949), of bacterial growth constant measurements.