Sphingobium terrigena sp. nov., isolated from gasoline-contaminated soil.

Abstract

A Gram-stain-negative, strictly aerobic bacterial strain, designated EO9T, was isolated from gasoline-contaminated soil in the Republic of Korea. Cells were non-motile short rods showing catalase- and oxidase-positive reactions. Growth was observed at 10-37 °C (optimum, 30 °C), at pH 6.0-9.0 (pH 6.5) and in the presence of 0-0.5 % (w/v) NaCl (0 %). Ubiquinone-10 (Q-10) and spermidine were identified as the predominant respiratory quinone and polyamine, respectively. Summed feature 8 (comprising C18:1ω7c/C18:1ω6c), summed feature 3 (comprising C16:1ω7c/C16:1ω6c), C16:0 and C14:0 2-OH were identified as major cellular fatty acids. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, sphingoglycolipid, phosphatidylglycerol and an unidentified phospholipid. The G+C content of the genomic DNA was 62.8 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain EO9T formed a tight phylogenetic lineage with Sphingobium xenophagum NBRC 107872T and Sphingobium hydrophobicum C1T within the genus Sphingobium. Strain EO9T was most closely related to S. xenophagum NBRC 107872T (97.2 %) and S. hydrophobicum C1T (97.2 %), but DNA-DNA relatedness levels between strain EO9T and the type strains of S. xenophagum and S. hydrophobicum were 37.1 and 36.8 % , respectively. Based on its phenotypic, chemotaxonomic and molecular features, strain EO9T clearly represents a novel species of the genus Sphingobium, for which the name Sphingobium terrigena sp. nov. is proposed. The type strain is EO9T (=KACC 19523T=JCM 32762T).