| Abstract |
Three Gram-staining-negative, strictly aerobic, non-pigmented, non-motile, rod-shaped bacterial strains, SP32(T) ( = SLM-1(T)), SR68 ( = SLM-3) and SP95 ( = SLM-2), were isolated from two water samples of a cold-water lake in Xinjiang province, China. Growth was observed at 4-25 °C and pH 6.0-9.0, and optimum growth occurred at 18-20 °C and at pH 7.0-7.5. Phylogenetic analysis of 16S rRNA gene sequences revealed that these isolates belonged to the family Rhodobacteraceae , but formed an evolutionary lineage distinct from other species of this family with validly published names. Strain SP32(T) showed the highest 16S rRNA gene sequence similarity (96.7%) to Rhodobacter veldkampii ATCC 35703(T), and the similarity to members of the genera Defluviimonas , Haematobacter and Pseudorhodobacter was respectively 95.8-96.4, 96.0-96.1 and 95.3-96.1%. The genomic DNA G+C content of strain SP32(T) was 67.6 mol%. The major fatty acids (>5%) were summed feature 8 (C(18 : 1)ω7c/C(18 : 1)ω6c) and11-methyl C(18 : 1)ω7c. Phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, one unidentified glycolipid and one unidentified polar lipid were the main polar lipids. Ubiquinone 10 (Q-10) was the sole respiratory quinone. Strain SP32(T) did not produce photosynthetic pigments and did not contain the gene pufM, by which it differed from the phototrophic species of the family Rhodobacteraceae . Based on its distinct phenotypic, chemotaxonomic and phylogenetic properties, strain SP32(T) represents a novel species in a novel genus within the family Rhodobacteraceae , for which we propose the name Frigidibacter albus gen. nov., sp. nov. The type strain of Frigidibacter albus is strain SP32(T) ( = SLM-1(T) = CGMCC 1.13995(T) = NBRC 109671(T)).
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