Identification of Bacillus amyloliquefaciens BI_2 and Its Antagonistic Activity Against Aspergillus flavus

The strain BI2 isolated from corn stalk of silage was G+ bacillus.By means of 16S rDNA sequence analysis,morphological observation,physiological examinatio and Biolog assay,BI2 was identified as Bacillus amyloliquefaciens.Its 16S rDNA sequence was 99.6% to B.amyloliquefaciens in similarity.Its antagonistic experiments were conducted with 12 plant pathogens including Fulvia fulva,Fusarium oxysporum,yeasts,mold fungi,food lactobacilla and pathogenic bacteria.The results show that BI2 possessed evident inhibitory activity to filamentous fungi,but had no evident effect on bacteria.It was further found that the supernatant of its broth after 36 h fermentation significantly inhibited the conidial germination and hyphal growth of Aspergillus flavus with the inhibition ratios of 67.4% and 74.8% respectively.It was also found that its an-tagonistic activity of the supernatant was not decreased although it was treated even at 120 ℃ for 20 min.