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采用血琼脂平板法,从菜园土壤中分离到8株代谢表面活性剂的菌株,比较各菌株的排油性、抑菌性,根据合成脂肽类物质表面活性素(Surfactin)和伊枯草菌素A(Iturin A)必需的sfp、ituD和lpa-14基因设计引物,结合PCR的方法筛选到一株具广谱抗菌性且含有sfp、ituD和lpa-14 3个关键基因的细菌XZ-173。经过生理生化试验测定和16S rDNA序列系统发育学分析,将其鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。通过红外光谱(FT-IR)分析该菌株代谢产物,初步鉴定为脂肽类物质,并对照高效液相色谱(HPLC)与标准品比对结果,确定含有Surfactin和Iturin A组分。该菌株产生的脂肽粗品能使纯水的表面张力降低至26.6 mN/m,临界胶束浓度(CMC)为500 mg/L,具有很好的乳化性能,对立枯丝核菌和青枯菌表现出很好的拮抗活性。因此,产脂肽细菌XZ-173是一株应用前景广阔的功能菌。
Eight strains of metabolic surfactant were isolated from vegetable garden soil by blood agar plate method. The oil-releasing and antibacterial properties of each strain were compared. According to the results of the synthetic lipopeptide Surfactin and iturin A (Iturin A) sfp, ituD and lpa-14 gene designed primers, combined with PCR screening a broad-spectrum antibacterial and contains sfp, ituD and lpa-14 three key genes of bacteria XZ-173. After physiological and biochemical tests and 16S rDNA sequence phylogenetic analysis, it was identified as Bacillus amyloliquefaciens. The metabolites of this strain were analyzed by FT-IR and identified as lipopeptides. By comparing the results of high performance liquid chromatography (HPLC) with standard samples, the products of Surfactin and Iturin A were determined. The lipopeptide crude product produced by this strain could reduce the surface tension of pure water to 26.6 mN / m and the critical micelle concentration (CMC) of 500 mg / L with good emulsifying ability against Rhizoctonia solani and R. solanacearum Showed good antagonistic activity. Therefore, lipogenic peptide bacteria XZ-173 is a promising application of functional bacteria.