Growth of Lactobacillus acidophilus in the Absence of Folic Acid

Abstract

Soška, Jiří (Kansas State University, Manhattan). Growth of Lactobacillus acidophilus in the absence of folic acid. J. Bacteriol. 91: 1840–1847. 1966.—A chemically defined medium, containing no folic acid, was used for the cultivation of Lactobacillus acidophilus R-26. In such a medium, the organism required thymine in addition to a deoxyriboside, purines, pyrimidines, and most amino acids. If thymine was present in this medium, an unlimited exponential growth was possible. The influence of the components of this medium on the growth is described. The concentration and type of adenine compounds in this medium were most important. Adenine and adenosine inhibited utilization of thymine, but not of thymidine, whereas adenylic acid inhibited recovery from amino acid starvation. In the absence of thymine or deoxyribosides, cells continued to grow in length, and after 3 hr a slow decline in viable count ensued.