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SUMMARY: Glucose utilization by a strain of Streptomyces griseus was studied. Under highly aerobic conditions, glucose was converted mainly to structural material and CO,, but under restricted aeration, lactic acid was formed. Pyruvic acid was also formed during the stages of most rapid growth. The metabolism of glucose was dependent upon the presence of phosphate, and the optimal hydrogenion concentration for both glucose oxidation and the rate of disappearance of inorganic phosphate was about pH 7. Phosphate esters, tentatively identified as glucose-1-phosphate and glucose-6-phosphate, were obtained in fluoride-inhibited systems. Glucose oxidation was depressed by M-sodium iodoacetate and Msodium arsenite but was stimulated by 10-2M-sodium arsenate ; 1 0 -3~-2 : 4-dinitrophenol and 10-sM-sodium azide had no effect. Streptomycin production was decreased by 3 x lO-*M-sodium arsenate but not by 10-2M-sodium fluoride or ~O-*Msodium iodoacetate. S. griseus metabolized members of the tricarboxylic acid cycle, although citrate and a-ketoglutarate gave much lower values of Qo, a t pH 7.3 than pyruvate, acetate, succinate, fumarate or malate. Ketoacids were produced in presence of arsenite from fumarate, malate, glucose, lactate, acetate, succinate, glutamate and citrate in descending order of yield. Except from fumarate, which yielded some material behaving like a-ketoglutarate, the product was chiefly p p v a t e .

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Banks has supervised the maintenance of our radioactivity measuring apparatus, and we are grateful for his unfailing help in this respect. We are also pleased to acknowledge our indebtedness to Miss M. E. Lake, and Miss M. McKerrow who have assisted us in a few of these experiments, and to Mr M. P. Curwen for help and advice on statistical matters.