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The strains capable of resistance against Verticillium dahliae Kleb were isolated and screened from the soils of cotton fields from several different provinces in China. A strain, coded DM-54, with a rather high antagonistic activity was obtained. Its morphological characteristics, physiological and biochemical properties and a 16 S rDNA sequence of this strain were further studied. The DM-54 strain was finally identified as a kind of Bacillusamyloliquefacien. Through a single factor experiment and an orthogonal experiment, the optimal shaking flask fermentation condition of strain DM-54 was found to be: media composed of 5% dextrin, 3% soy peptone, 0.02% MgSO4, 0.01% CaCl2, initial pH 7.0 and 10% inoculum volume, media volume 30/250 (mL/mL), fermentation temperature at 32ºC, rotating speed 200 r∙min−1, fermentation time of 48 h. Its antagonistic activity was distinguished to be elevated, at about 39.9%. Our research offers an effective means for the massive production of antagonistic proteins. |
