Identification Of Brevibacillus Brevis XDH And Isolation And Characterization Of Its Antibacterial Substance

a'311, isolated from soil, exhibited potent growth inhibitory activities against several pathogens, such as Fusarium oxysporum f.sp. vasinfectum, Fusarium oxysporum, Phyllosticta thesefolia, Escherichia coli, Pasteurella multocida, Staphylococcus aureus and Bacillus sp. It was identified as Brevibacillus brevis XDH by 16S rDNA analysis, conformation, physiological and biochemical features. The best fermentation condition was chosen, and the antibacterial substance was isolated and extracted. The main results were as following:1 a'311 was identified as Brevibacillus brevis XDH by 16S rDNA analysis, conformation, physiological and biochemical features. The 16S rDNA sequence has been registered at Genbank under the accession number DQ279738.2 The best fermentation condition was glucose 16g,starch 2.5g,peptone 10g,bean powder 26g,corn plasm 1.0g,NaCl 7.5g,(NH4)2SO4 4.0g,distilled water1000mL,30℃, 200rpm and 48h.3 The antibacterial substance can be isolated from other groups by salting out with 40% (NH4)2SO4 and Sephadex G-50 analysis. The best HPLC flow phase was chosen when methanol and acetonitrile as organic phase. The HPLC condition was methanol:0.4% acetic acid(28:72,v/v), Kromasil C18 column(250×4.6mm,5μm), flow rate 1.0mL/min, column temperature 30℃and detection wavelength 270nm.The results showed that at least two groups were isolated with the retention time 6.225min and 10.899min, respectively. The preparation column was used to prepare the antibacterial substance under the condition of Kromasil C18 column (250×10mm,5μm), flow rate 3.5mL/min,column temperature 30℃and detection wavelength 270nm. Two...