Nutrition of Streptococcus lactis

Abstract

All cultures required pantothenic acid, nicotinic acid, and biotin. 18 of the 21 strains tested required thiamine; only 1/3 of the cultures required riboflavin. All strains were able to grow without added folic acid and pyridoxine, but the latter vitamin stimulated the growth of all cultures. The amino acid requirements are complex, a minimum of 14 being necessary to effect prompt growth. All cultures were able to grow without added tryptophane. Glutamine and asparagine were necessary for the initiation of growth for all cultures tested. Str. cremoris, a closely allied var. or sp., appears to have similar nutritive requirements.