Sphingobium fluviale sp. nov., isolated from a river.

Abstract

A Gram-stain-negative, rod-shaped, non-motile, poly-β-hydroxybutyrate-accumulating and aerobic bacterial strain, designated CHR27T, was isolated and characterized by using the polyphasic taxonomy approach. The results of phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of an up-to-date bacterial core gene set (92 protein clusters) indicated that strain CHR27T is affiliated with species in the genus Sphingobium. 16S rRNA gene sequence similarity results indicated that strain CHR27T was closely related to species of the genus Sphingobium (94.3-97.0 %), and had the highest sequence similarity to Sphingobium qiguonii X23T (97.0 %). Strain CHR27T showed 19.4-22.1 % digital DNA-DNA hybridization values and 73.2-74.8 % average nucleotide identity values with the strains of other Sphingobium species. Optimal growth occurred at 25 °C, pH 7.5 and in the absence of NaCl. The major fatty acids of strain CHR27T were C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c). The predominant hydroxy fatty acid was C14 : 0 2-OH. The polar lipid profile consisted of a mixture of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidyldimethylethanolamine, two unidentified sphingoglycolipids and an unidentified aminophospholipid. Strain CHR27T contained spermidine as the major polyamine and putrescine as a minor component. The only isoprenoid quinone was ubiquinone-10. The genomic DNA G+C content of strain CHR27Twas 61.8 mol%. On the basis of the phylogenetic inference and phenotypic data, strain CHR27T was considered a representative of a novel species within the genus Sphingobium. The name Sphingobium fluviale sp. nov. is proposed, with strain CHR27T (=BCRC 81121T=LMG 30596T=KCTC 62510T) as the type strain.