放线菌PY-C-21菌株鉴定及其活性产物的结构分析

拮抗性放线菌是开发高效安全食品生物防腐剂的基础。本研究从广州及其周边采集的土样中通过平板稀释法获得190株放线菌，分别采用琼脂块法和牛津杯定量扩散法进行初筛和复筛，然后通过16S rDNA序列分析，结合形态特征、培养特性和生理生化特性，对菌株PY-C-21进行鉴定。采用溶剂萃取法提取菌株PY-C-21发酵产物的活性成分，接着采用硅胶柱层析分离该菌株的粗提取物，再通过高效液相色谱、薄层色谱和制备色谱制备纯品化合物，采用气质比对法和高分辨质谱法等分析具有抑菌活性的单体化合物。结果表明，菌株PY-C-21具有稳定且广谱抗菌活性，并被鉴定为毒三素链霉菌（Streptomyces toxytricini），该菌株发酵产物的活性物质主要为邻苯二甲酸二丁酯、苯甲酸、2,2-亚甲基双（4-甲基-6-叔丁基苯酚）和邻苯二甲酸二(2-乙基己)酯。
Antagonistic actinomycetes are the important microbes for development of efficient and safe biological food preservatives. In this study, a total of 190 actinomycete strains were separated using the plate dilution method for soil samples collected from Guangzhou and its surrounding areas, and then preliminary screening and rescreening were conducted using the agar disc and Oxford cylinder diffusion methods, respectively. Strain PY-C-21 was identified by 16S rDNA sequence analysis, morphological and cultural characteristics, and physiological and biochemical characteristics. The active ingredients of the fermentation products from PY-C-21 were extracted using the solvent extraction method, and then the crude extracts of the PY-C-21 fermentation products were purified by silica gel column chromatography. The pure compounds were obtained by high-performance liquid chromatography, thin layer chromatography, and preparative chromatography, and monomeric compounds with antibacterial effects were analyzed by gas chromatography mass spectrometry, and high resolution mass spectrometry. The results showed that PY-C-21 possessed a stable and broad-spectrum antimicrobial activity, and was identified as Streptomyces toxytricini. The main active products in the fermentation products were identified as dibutyl phthalate, benzoic acid, phenol, 2,2?-methylenebis(6-tert-butyl-4-methylphenol), and bis(2-ethylhexyl) phthalate.