YEAST GROWTH METHOD FOR ASSAY OF BIOTIN ACTIVITY

Open Access
Publisher Website
Google Scholar
Abstract
Routine assays of biotin, performed according to the yeast growth method of White & Munns, sometimes gave irregular results, i.e., an exceptionally vigorous growth of the yeast in biotin-free medium. This gave rise to uncertainty as regards the functioning of the method and the reliability of the results. The number of anomalous cases increased when the industrial stages A2 and A5 of baker's yeast were used as seed yeast instead of the pure culture stage R3. Cultures which had been contaminated with the wild yeast Pichia orientalis, isolated from commercial baker's yeast, or with a Candida utilis collection strain, revealed that the anomaly was due to an infection of the seed yeast. In the case of a slight infection, the wild yeast, not needing biotin, increases vigorously in the biotin-free medium, although in a biotin-containing medium baker's yeast is able to compete successfully.