Isolation of Sphingopyxis kveilinensis sp. nov., a Potential Antibiotic-Degrading Bacterium, from a Karst Wetland.

Abstract

A Gram-stain-negative, aerobic, mesophilic, motile, rod-shaped bacterium, designated strain TUF1^T, was isolated from a karst wetland in south-west China. It was demonstrated to be capable of growing on plates containing oxytetracycline, streptomycin, or ofloxacin as the sole carbon source. Phylogenetic analysis of the 16S rRNA gene sequence revealed that this organism belongs to the genus Sphingopyxis and is closely related to S. chilensis S37^T (99.17%) and S. alaskensis RB2256^T (99.12%). The orthologous average nucleotide identity values (OrthoANIu, 84.42% and 87.53%) and digital DNA-DNA hybridization values (dDDH, 41.7% and 48.9%) between strain TUF1^T and its close relatives were all below the standard recommended threshold values for species discrimination. The genomic DNA G + C content was determined to be 64.7%. The predominant cellular fatty acids were identified as summed feature 8 (C_18:1ω7c and/or C_18:1ω6c) and summed feature 3 (C_16:1ω7c and/or C_16:1ω6c). The major polar lipids found to be diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, and sphingoglycolipid. The sole respiratory quinone present was ubiquinone Q10. Based on the phylogenetic, biochemical, physiological, and chemotaxonomic analyses, strain TUF1^T represents a novel species of the genus Sphingopyxis. The designation "Sphingopyxis kveilinensis sp. nov." is proposed as the name for this novel species, and the strain TUF1^T (= CGMCC1.62043 ^T = JCM36394^T) is designated as the type strain.