高产5-氨基乙酰丙酸光合细菌株的分离鉴定

从不同生态环境中分离培养出20株光合细菌,进行5-氨基乙酰丙酸(5-ALA)的产量检测,筛选出一株分离自广州市云溪公园池塘底泥的菌株R5,其5-ALA产量最高,达4.92 mg/L.为了确定菌株R5的分类学地位,对该菌株的形态学、碳源利用情况等生理生化特性进行了研究,表明该菌株符合红假单胞菌属的生物学特征;以菌株R5基因组DNA为模板PCR扩增16S rDNA基因,对PCR产物进行了序列测定,将所测得的核酸序列与相关细菌的16S rRNA序列进行比对,并构建进化树进行系统发育分析,发现菌株R5与沼泽红假单胞菌株KUGB306(Rhodop-seudom onas palustrisKUGB306)形成一个类群,序列同源性为99%.故最后确定该高产5-ALA的菌株属于红假单胞菌属(Rhodopseudom onas).

Isolation and identification of a strain of photosynthetic bacteria with high-yield production of 5-aminolevulinic acid

5-aminolevulinic acid(5-ALA) is a derivative of 5-carbon amino acid and is found in most living organisms with photosynthetic bacteria having the highest extra-cellular production of 5-ALA.In this study,the productions of 5-ALA by 20 photosynthetic bacteria strains from different habitats were determined.Strain R5 isolated from the bottom mud of a pond in Yunxi park,Guangzhou,had the highest production of 5-ALA(4.92 mg/L).Its morphology and ability to utilize different carbon sources were consistent with the species of the genus Rhodopseudomonas.A phylogenetic tree constructed by the neighbour joining method based on the sequence of 16S rRNA fragment showed that strain R5 was clustered with Rhodopseudomonas palustrisKUGB306,with homology being 99%.Strain R5 with the highest production of 5-ALA should therefore be classified in the genus Rhodopseudomonas.