Frigidibacter albus gen. nov., sp. nov., a novel member of the family Rhodobacteraceae isolated from lake water

Abstract

Three Gram-staining-negative, strictly aerobic, non-pigmented, non-motile, rod-shaped bacterial strains, SP32 T (5SLM-1 T), SR68 (5SLM-3) and SP95 (5SLM-2), were isolated from two water samples of a cold-water lake in Xinjiang province, China. Growth was observed at 4-25 6C and pH 6.0-9.0, and optimum growth occurred at 18-20 6C 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 v7c/C 18 : 1 v6c) and11-methyl C 18 : 1 v7c. 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 (5SLM-1 T 5CGMCC 1.13995 T 5NBRC 109671 T).

Proposal for transfer of Defluviimonas alba to the genus Frigidibacter as Frigidibacter mobilis nom. nov

“…The description is as given by Li and Zhou [10] with the following modifications. Some species may contain aminolipids and lipids.…”

“…Therefore, at the time of writing, the genus Defluviimonas comprises five species with validly published names, Defluviimonas denitrificans [1], Defluviimonas aestuarii [6], Defluviimonas aquaemixtae [7], Defluviimonas alba [8] and Defluviimonas nitratireducens [9]. Another genus Frigidibacter was introduced by Li and Zhou in 2015 to accommodate only the species Frigidibacter albus [10]. The type strain of the type species was SP32 T , which was isolated from a water sample of a cold-water lake in Xinjiang province, PR China [10].…”

“…Another genus Frigidibacter was introduced by Li and Zhou in 2015 to accommodate only the species Frigidibacter albus [10]. The type strain of the type species was SP32 T , which was isolated from a water sample of a cold-water lake in Xinjiang province, PR China [10]. In the process of investigating the taxonomic diversity of the family Rhodobacteraceae, it was found that the type strain Defluviimonas alba cai42 T was the most closely related to SP32 T .…”

“…As shown in Table S3, the fatty acid profiles of the two strains were similar, with summed feature 8 (C 18 : 1 ω7c and/ or C 18 : 1 ω6c) as the major component, C 18 : 1 ω7c 11-methyl and C 16 : 0 as the minor ones. The polar lipids of cai42 T and SP32 T from the species description [8,10] were compared in this study. Five kinds of polar lipids including phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), glycolipid (GL) and phospholipid (PL) were found in cai42 T and SP32 T .…”

Botryococcus braunii for the production of hydrocarbons and exopolysaccharides and the role of associated bacteria

“…The OTUs 45 and 69 blast searches in NCBI database showed the closest neighbours to be Frigidibacter albus, Paracoccus sediminis and Nioella nitratireducens (Table 3.2). All three neighbours were isolated from water environments (Pan et al 2014, Li and Zhou 2015, Rajasabapathy et al 2015.…”