Abstract
1. The best condition for the biosynthesis of biotin from desthiobiotin by the washed cells of Saccharomyces cerevisiae was found as follows: The cells cultured in a liquid medium containing a suboptimal amount (20mμg per 100ml) of DL-desthiobiotin for 1 to 3 days were incubated in the reaction mixture containing DL-desthiobiotin (2×10-7 M) and glucose at 37° without shaking.
2. Sulfur necessary for the biosynthesis of biotin seems to be sufficiently present in the cells, because the addition of several sulfur compounds did not increase the formation of biotin. The synthesized vitamin was practically restricted in the cells and 87 per cent of it was present in a bound form.
