Iturin produced by Bacillus pumilus HY1 from Korean soybean sauce ( kanjang) inhibits growth of aflatoxin producing fungi

A new strain of Bacillus pumilus, designated HY1, was isolated from Korean soybean sauce ( kanjang). This classification was based on morphological, physiological, and chemotaxonomic features of the organism that identified it as a Gram-positive bacillus, and confirmed by 16S rDNA based phylogenetic analysis. Strain HY1 showed strong antifungal activity against the aflatoxin-producing fungi Aspergillus flavus and Aspergillus parasiticus, two common contaminants of fermented soybean foods. MALDI-TOF mass analysis revealed that the antifungal compound was similar to the known lipopeptide iturin. Iturin purified from strain HY1 had three isoforms with protonated masses of m/z 1,043.4, 1,057.4, and 1,071.4, and different structures in combination with Na + ion using MALDI-TOF MS. Purified iturin from HY1 also exhibited antifungal activity against A. flavus and A. parasiticus.