Abstract
The growth-stimulation of Lactobacillus fermenti or Kloeckera apiculata by the aseptic addition of such S-alkyl-thiamines as methyl-(I), ethyl-(II), benzyl-(III), 3,4,5-trimethoxybenzyl-(IV) and triphehylmethyl-(V) ether of thiamine or phosphates of (IV) and (V) to the thiamine-free broth, was investigated : (V) or its phosphate was proved to show one-tenth the growth-stimulation of thiamine both on Lactobacillus and Kloeckera, while the other compounds were shown to be practically inert. (III) or (IV) was proved to have one-thousandth the potency of thiamine on Lactobacillus assay and the others were far less potent than these compounds. Bioautography of (V) using L. fermenti revealed that its microbiological activity did not originate in the thiamine contaminated. The addition of (I), (II) or (III) each at the concentration of 1μg to 10 mg to the broth containing 0.05 μg of thiamine, resulted in noninhibition to the growth of both Lactobacillus and Kloeckera. S-Alkyl-thiamines, therefore, seem not to compete with thiamine.
