一株富含类胡萝卜素光合细菌的分离鉴定

从不同生物环境中分离紫色非硫菌,测定其类胡萝卜素含量,筛选出富含类胡萝卜素的菌株.对该菌株的形态学特征、碳氮源利用情况、最适生长pH值及盐度等生物学特征进行研究;利用PCR技术扩增其16S rRNA基因,测序后进行16S rRNA基因序列分析,研究其分类地位.结果:分离自暨南大学明湖底泥的菌株R2,在所分离的8株紫色非硫菌中,类胡萝卜素质量分数最高,为4.83 mg/g(干菌体),该菌株符合红游动菌属(Rhodoplanes)的生物学特性,其最适生长pH为7.0,盐度为0.2%;16S rRNA基因的分子系统学分析表明,该菌株与红游动菌属的Rhodoplanessp.HA17相似性为99.4%.可确定筛选出一株高产类胡萝卜素的菌株,该菌株属于红游动菌属(Rhodoplanes).

Isolation and identification of a strain of photosynthetic bacteria with high -yield production of carotenoid pigments

Purple nonsulfur bacteria were isolated from different habitats.The contents of carotenoid pigments in their dry cells were measured and a strain with high-yield production was selected.Its biological characteristics including morphology,the ability to utilize different carbon and nitrogen sources,the optimal pH value and salt concentration for growth were studied.The 16S rRNA gene was amplified and sequenced.The sequence was compared with those of related species using ClustalX.Strain R2 isolated from the bottom mud of Minghu pond in Jinan University yielded a maximum production of carotenoids,4.83 mg/g dry cells.The biological characteristics suggested that Strain R2 was closely related to the species of the genus Rhodoplanes.The strain showed an optimal growth at pH 7.0 and 0.2% NaCl.Based on 16S rDNA sequences,a phylogenetic tree was constructed.Strain R2 and Rhodoplanes sp.HA17 falled in one clade,and sequence similarity between them was 99.4%.The strain of purple nonsulfur bacteria with high-yield production of carotenoid pigments was isolated and classified in the genus Rhodoplanes.