Abstract
An agar-plate diffusion method for the microbioassay of inositol in natural products using both Kloeckera apiculata and Saccharomyces carlsbergensis as test organisms was attempted. In case of K. apiculata assay, the inositol requirement of the organism was strictly exacting than that of S. carlsbergensis, though it was susceptible to temperature on growth. The growth zone on the assay plate of K. apiculata was more clear, sharply-defined and reproducible than that of S. carlsbergensis and a linear response to pure inositol solution containing 10 to 400μg per ml was demonstrated with the probable errors of 10% on statistical analysis. The inositol contents in several natural products obtained by cup-plate method were nearly equal to those obtained with turbidimetric one and the recovery experiments were satisfactorily successful. This method is simple, accurate and available for the routine assay of inositol in biological materials.
