Abstract
The presence of an unknown substance in the mycelium of Aspergillus oryzae which was previously reported to stimulate the growth of Streptococcus faecalis 10C1 in the lipoic acid assay medium was confirmed by a method of bioautography using water-saturated n-butanol as the developing solvent and Stc. faecalis 10C1 as the test organism. The substance showed Rf value of 0.75-0.8,while α-lipoic acid and β-lipoic acid were detected at Rf 0.92 and 0.65,respectively. The behaviour of the substance on several ion exchange resins was compared with that of lipoic acid. Consequently, a complete separation of the substance from lipoic acid was successfully carried out by passing a hydrolysate of the mycelium through a column of Amberlite IR-4B.
