Antifungal activity of fatty acid salts against Penicillium pinophilum

Abstract

The antifungal activity of nine fatty acid salts (butyrate, caproate, caprylate, caprate, laurate, myristate, oleate, linoleate, and linolenate) was tested on the spores of Penicillium pinophilum NBRC 6345 and Penicillium digitatum NBRC 9651. Potassium caprate showed the strongest antifungal activity at 4 log-units. At incubation times of 180 min, potassium caprylate and potassium laurate showed antifungal activities of 2 log-units against P. pinophilum NBRC 6345. These results suggest medium-chain fatty acid salts showed the highest antifungal activity. The minimum inhibitor y concentration of potassium caprate against P. pinophilum NBRC 6345 was 175 mM, and >175 mM for other fatty acid salts. When mixed with short-chain fatty acid salts (potassium butyrate, potassium caproate) or medium-chain fatty acid salts (potassium caprylate or potassium laurate), potassium caprate caused a 4 log-unit reduction in fungal growth; however, when mixed with long-chain fatty acid salts (potassium myristate, potassium oleate, potassium linoleate, or potassium linolenate) it had no antifungal effect. Thus, long-chain fatty acid salts inhibited antifungal activity of C10K. We also evaluated the ability of C10K to inhibit fungal growth on orange rind. C10K effectively inhibited P. pinophilum NBRC 6345 growth on orange rind. Thus, C10K shows promise as an antifungal agent.