基于甘草苷生物合成的甘草内生细菌的筛选及鉴定

Biosynthesis of liquiritin in endophytic bacterium from Glycyrrhiza uralensis and its identification

目的:基于甘草苷的生物合成,筛选甘草苷产生菌。方法:采用平板分离法从甘草叶中分离内生细菌;采用滤纸片法筛选内生细菌的抑菌活性;以甘草苷为对照,采用高效液相色谱(high performance liquid chromatography,HPLC)法对内生细菌发酵液进行分析,同时采用硅胶柱色谱分离法从目的菌株中分离得到甘草苷;结合形态特征观察及16S rDNA序列同源性分析对目的菌株进行鉴定。结果:从甘草叶中分离得到32株内生细菌,其中有28株内生细菌具有抑菌活性,并在内生细菌GYX9发酵液中分离得到甘草苷,经鉴定GYX9为嗜根寡养单孢菌(Stenotrophomonas rhizophila)。结论:甘草叶内生细菌GYX9可以产生甘草苷,为微生物发酵法生产甘草苷提供理论依据。

Objective:To screen the liquiritin-producing endophytic bacterium based on the biosynthesis of liquiritin.Methods:Endophytic bacteria were isolated from the leaf of Glycyrrhiza uralensis by the methods of plate cultivation,and the antimicrobial activities of the endophytic bacteria were screened by filter paper method.Meanwhile,with liquiritin as reference substances,the fermentation of the endophytic bacteria was analyzed by HPLC,and liquiritin was isolated and purified by column chromatography from the fermentation broth of the target strain.The target endophytic bacterium was identified by the 16 S rDNA sequence homology and their physiological and biochemical characteristics.Results:Among 32 strains of endophytic bacteria isolated from the leaf of G.uralensis,28 strains were found antibacterial activity.Liquiritin was separated from the culture of GYX9 by the silica gel column chromatography,and the target bacterium GYX9 was identified as Stenotrophomonas rhizophila.Conclusion:GYX9 can produce liquiritin,which provides a theoretical basis for the production of liquiritin by microbial fermentation.