SOME FACTORS AFFECTING THE NUTRITIONAL REQUIREMENTS OF STREPTOCOCCUS FAECALIS

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Abstract
A synthetic medium was developed which gives a max. growth for S. faecalis (A. T. C. C. 6057) at the end of 16 hrs. Using this basal medium the essential amino acids added were arginine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, threonine, tryptophan, and valine. The stimulatory amino acids are alanine, cystine, phenylalanine, and serine. Serine is an essential amino acid when the basal medium is sterilized with a Seitz filter. Serine activity for the organism results from a soln. of cystine and glucose autoclaved together. When the substrate is autoclaved, the organism is slightly inhibited at higher concns. of cystine. When the substrate is sterilized with a Seitz filter, the higher concns. of cystine produce a decided inhibition on the organism.