2017 ASHS Annual Conference

This study was carried out to investigate the characteristics of Bacillus amyloliquefaciens Y1 isolated from soybean cake and to cultivate the strain without autoclave. Y1 secreted siderophore and several lytic enzymes such as gelatinase, lipase and protease. In addition, the strain released an antifungal compound which was identified as a Bacillomycin D using HPLC, nuclear magnetic resonance (NMR), liquid chromatography mass spectrometry (LC-MS), and high resolution mass spectrometry (HR-MS). Cost effective medium was prepared and antifungal activity was performed to compare between Cost effective and CP medium (colloidal chitin with potato dextrose). Y1 inhibited all tested pathogenic fungi (Rhizoctonia solani, Colletotrichum gloeosporioides, Botrytis cinerea, Phytophthora capsici, Fusarium oxysporum and F. graminearum); however, the antifungal activities in CP medium were a little bit higher than BB medium (blue brown). When the culture filtrate of Y1 was used to test the antifungal activity, the longer the incubation period and the higher the treated concentration, the stronger antifungal activities were shown. Especially, the growth inhibition rate for R. solani and B. cinerea was 100% when the culture filtrate cultured for 15 days was treated with 50% concentration. The properties of Y1 culture were investigated after Y1 was inoculated on autoclaved and H₂O₂ treated medium. As a result, cell growth was the highest after 3 days in both media. The pH values of both cultures were kept at 8.0, but the value of 8.0 was reached at 2 days and 14 days for the autoclaved medium and H₂O₂ treated medium, respectively. The surface tension was 38.3mN m^-1 in the autoclaved medium and 43.8mN m^-1 in the H₂O₂ treated medium. Chitinase, β-1,3-glucanase and protease activities were 4. 7, 8.4 and 7.4 unit ㎖^-1 in the autoclaved medium and 3.3, 1.1 and 15.0unit ㎖^-1 in the H₂O₂ treated medium respectively. Therefore, based on these results, it is expected that Y1 can be cultured without autoclave sterilization and used in agriculture.