RESUMO
13 isolates producing Coenzyme Q10 (CoQ10) of purple non sulfur photosynthetic bacteria were enriched out of pond sludge, one isolate named 2c was selected based on its high CoQ10 content and identified systematically. The gram-negative and short-rod shaped strain 2c is 0.6microm - 0.9microm x 1.2microm - 2.0 microm, has one long flagellum on one end of the cell and contains lamellar intracytoplasmic membrane(ICM) system parallel to cytoplasmic membrane. Cultures produce red pigments in the light. Live cells under phototrophic conditions contain bacteriochlorophyll a and carotenoids. 2c grows anaerobically in the light and aerobically in the dark. Optimal growth occurs at 30degreesC - 35degreesC and at pH7.0 -pH8.0. Various organic compounds are used as photosynthetic electron donors and carbon sources. Peptone and (NH4 )2SO4 are its better nitride source,yeast extracts stimulates its growth. A phylogenetic analysis based on 16S rDNA gene sequences reveales that strain 2c gathers a cluster with 3 strains of Rhodopseudomonas palustris whose accession number in GenBank are AY751758, DQ001155, DQ001158, respectively. 2c subcultures 15 generations stably at least. The results presented here demonstrated strain 2c is Rhodopseudomonas palustris.