Identification of Antagonistic Bacillus HY-5 and Its Antimicrobial Compositions from Mangrove Against Specific Salt Resistance Fungi of Marine Dried Fish

Objective:To discover a new antagonistic bacillus aganist specific fungi possessed high salt resistance of marine dry fish. Method:A strain with high antimicrobial activity named HY-5 was screened from seawater,sea mud,leaves and bark from mangroves of Zhanjiang by agar diffusion method and plate method. HY-5 was identified as Bacillus amyloliquefaciens by traditional cell morphology,physiological,biochemical experiments and 16S rDNA sequence analysis. The supernatant of HY-5 fermentation with obvious antibacterial effect on 17 strains fungi which isolated from moldy marine dried fish was determined by cup-dish method. And the fermentation broth contained two groups of antimicrobial lipopeptide surfactin(994.6,1008.6,1022.5 and 1036.6)and iturin(1016.5,1030.5,1044.4 and 1058.3)by LC-MS method. Conclusion:The crude extract of Bacillus amyloliquefaciens HY-5 contained antimicrobial lipopeptides which had strong antagonistic effect on fungi isolated from the marine dry fish.