Abstract
It has been occasionally recognized that the contamination of vitamin active substances from cotton stoppers causes certain difficulties in the microbiological determination of biotin or inositol using Saccharomyces carlsbergensis. The amounts of inositol- and biotin-active substances contained in various cottons were assayed with the yeast, with regard to the total amounts and those of the free forms respectively. Rf values of the inositol- active substance of hot water extract and acid hydrolyzate of cotton were found to be identical with that of crystalline inositol. The biotin activity of cotton extract was completely inactivated by the treatment with egg white. When bioautographed, cotton extract as well as crystalline biotin showed two growth zones. It appears that the one spot corresponds to biotin and the other is that of biotin-D-sulfoxide formed from biotin by oxidation during the course of paper chromatography.
