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Inhibition of growth and toxin production of ochratoxigenic Aspergillus spp. by isolated bacteria
Korean J. Microbiol 2019;55(3):226-233
Published online September 30, 2019
© 2019 The Microbiological Society of Korea.

Ji-Seon Hwang, Ho-Yeong Choi, and Hong-Gyu Song*

Department of Biological Sciences, Kangwon National University, Chuncheon 24341, Republic of Korea
Correspondence to: *E-mail:; Tel.: +82-33-250-8545; Fax: +82-33-259-5665
Received July 25, 2019; Revised August 14, 2019; Accepted August 14, 2019.
Ochratoxin A (OTA) that is one of mycotoxins produced mainly by Aspergillus spp. is a common contaminant of stored grains and poses health hazards to human and livestock. The aim of this study is to explore the ability of isolated bacteria Bacillus subtilis AF13 and Streptomyces shenzhenensis YR226 to inhibit growth and OTA production of 3 ochratoxigenic Aspergillus strains. The antifungal activity against mycelial growth and sporulation of Aspergillus strains was examined by coculture with AF13 and YR226 on potato dextrose agar plate. AF13 and YR226 reduced 77.58 and 78.48% of fungal colony radius, respectively, and both strains inhibited fungal sporulation up to 99% in 10 days of incubation. YR226 also reduced more than 91% of spore germination of 3 fungal strains. When Aspergillus strains were cocultured with AF13 or YR226 in yeast extract sucrose medium, mycelial growth and OTA production decreased in all three fungal strains. In particular, AF13 completely inhibited the mycelial growth of A. alutaceus and inhibited its OTA production by 99%, and YR226 also reduced mycelial growth and toxin production up to 99%, respectively. Antimicrobial substances produced by AF13 and YR226 included siderophore, chitinase, protease, β-1,3-glucanase and biosurfactant. These results suggest that AF13 and YR226 can be used in a biological method to prevent valuable crops against mycotoxigenic fungi, and therefore decrease economic damage in agriculture and feed industry.
Keywords : Bacillus subtilis AF13, Streptomyces shenzhenensis YR226, antifungal activity, antifungal substances, ochratoxin A

September 2019, 55 (3)