Production of Riboflavin and Allied Substances during the Growth of C. diphtheriæ

WHILE studying, by paper partition chromatography 1 , the utilization of amino-acids during the growth of the Park Williams No. 8 strain of C. diphtheriæ , we noted a strong yellow fluorescence with ultra-violet light of culture filtrates of the organism grown on a casein hydrolysate medium prepared essentially according to the method of Mueller and Miller 2 . When such culture filtrates were run on chromatograms using n -butanol-acetic acid as the solvent 3 , two strongly fluorescent yellow spots were observed when the dried paper was placed under an ultra-violet lamp. Neither of these spots gave any colour when the paper was sprayed with 0·1 per cent (w./v.) ninhydrin in chloroform. One of them was in a position approximating to that occupied by proline and the other to that occupied by the basic amino-acids.