An antimicrobial substance produced by Corynebacterium kusaya which was the dominant organism in curing brine of Kusaya, a cured and dried fish, was partially purified by the use of gel-filtration and fractionation by ion exchange cellulose. The purified fraction inhibited the growth of St. aureus at a concentration corresponding to 0.5ppm in terms of dry weight. The substance had a fairly wide, but unstable, antimicrobial spectrum. The antimicrobial activity of the substance was lost by the treatment of organic solvents such as ethanol, butanol, ether and acetone, by the exposure at pH lower than 3.0 or higher than 11.0 as well as by heating at 50°C for 30 minutes. Properties of the partially purified fraction suggested that the substance was a protein of a high molecular weight.
The possible role of the organism in manufacturing Kusaya was discussed.