Purification And Characteristic Analysis Of Antifungal Substances From Bacillus Amyloliquefaciens X-278

Bacillus amyloliquefaciens X-278was isolated from cotton rhizosphere and itshowed strong inhibition against Verticillium dahilae,and significant control effect oncotton Verticillium wilt.In order to study the characteristics of antifungal proteins isolated fromB.amyloliquefaciens X-278, crude proteins was extracted from precipitation of the cellculture of strain X-278with ammonium sulphate and determined protease stability andthermal stability. The result showed that strain X-278showed significantly control effecton cotton verticillium wilt with ammonium sulphate at50%saturation, precipitation fromthe crude protein extracts was insensitive to proteinase K, was sensitive to trypsin. Theactivity of the antifungal substrates were investigated under different temperatures. Theantifungal activity of the substrate at40℃was no significant difference when it comparedwith control, while the antifungal activity decreased at121℃and showed significantdifference compared with the control. However, the crude protein extracts still retained72%compared to the control and diameter of inhibition zone was13.6mm after heattreatments for30min under121℃. Results indicated that part of the antifungal extracts ofB.amyloliquefaciens X-278were heat-resistant substance and the antifungal extracts ofB.amyloliquefaciens X-278were several substrates with different traits.The antifungal protein precipitated by salt out with50%ammonium sulfate wasseparated by SDS-PAGE was analysed by PMF. The PMF result of X-278was not similarto any other proteins in Mascot. The result showed that the lipopeptide antibiotics crudwas played apart in antifungal proteins isolated from B.amyloliquefaciens X-278.In this paper, lipopeptide antibiotics crude extracted by hydrochloric acid wascomposed of many components after analyzed by TLC and HPLC. The lipopeptidecompound showed a similar retention time to the standard sample of surfactin in HPLCand TLC analyses. In addition, B.amyloliquefaciens X-278can produce lipopeptides andthe antifungal substance contained surfactin.