Sphingorhabdus buctiana sp. nov., isolated from fresh water, and reclassification of Sphingopyxis contaminans as Sphingorhabdus contaminans comb. nov.

A Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacterial strain, designated T5T, was isolated from the Chishui River in Maotai town, Guizhou Province, Southwest of China. Strain T5T was found to grow optimally at pH 9.0 and 25 °C. The 16S rRNA gene sequence analysis indicated that strain T5T belongs to the family Sphingomonadaceae within the phylum Proteobacteria; the strain T5T clustered with the type strains of Sphingopyxis contaminans, Sphingorhabdus wooponensis and Sphingorhabdus rigui, with which it exhibits 16S rRNA gene sequence similarity values of 96.2-96.9%. The DNA G+C content was 58.5 mol%. The major respiratory quinone was Q-10 and the major polar lipid was phosphatidylethanolamine. The major polyamine was homospermidine and the major fatty acids were C18:1 ω7c (37.5%) and C16:1 ω7c (30.1%). On the basis of phylogenetic, phenotypic and genetic data, strain T5T represents a novel species of the genus Sphingorhabdus, for which the name Sphingorhabdus buctiana sp. nov. is proposed. The type strain is T5T (= CGMCC 1.12929T = JCM 30114T). It is also proposed that Sphingopyxis contaminans should be reclassified as a member of the genus Sphingorhabdus.