Biotin and the metabolism of Lactobacillus arabinosus.

It is known that the requirement of microorganisms for certain growth factors is influenced by the nutritive medium in a manner analogous to the effect of dietary regimen of animals on their vitamin requirements. In this connection it was found by Williams and Fieger (1) that oleic acid could substitute for biotin in the growth of Lactobacillus casei under their experimental conditions. Axelrod et al. (2) have recently shown that this is also the case for Lactobacillus arabinosus. Koser et al. (3) were able to demonstrate that, for To&a cremoris, aspartic acid could largely substitute for biotin. More recently Stokes, Larsen, and Gunness (4) have shown a definite relationship between biotin and aspartic acid and were able to demonstrate that aspartic acid synthesis resulted when biotin was present, Since Williams and Fieger (1) demonstrated that oleic acid does not cause biotin synthesis, it appears possible that biotin is responsible for synthesis of both aspartic acid and oleic acid. The purpose of the investigation herein reported is to elucidate the relationship between biotin and these two nutrilites and to determine whether there is a relationship between aspartic acid and oleic acid other than their common connection with biotin.