Mykologie und Hygiene,

Classification of strain W-50T, which was isolated from a wastewater treatment plant, was investigated by a polyphasic approach. Cells of strain W-50T were Gram-negative, strictly aerobic, oxidase-positive and yellow-pigmented. Ubiquinone Q-10 was the main respiratory lipoquinone system and polar lipid fingerprints were characterized by the presence of a sphingoglycolipid, suggesting that strain W-50T belongs to the a-4 subclass of the Proteobacteria. Sequencing and comparative analyses of the 16S rRNA gene of strain W-50T supported its chemotaxonomic allocation as an a-4 proteobacterium. The most closely related established taxa were species of the genus Sphingopyxis, including Sphingopyxis macrogoltabida (97<3 % similarity) and Sphingopyxis terrae (96<4 % similarity), and Sphingomonas taejonensis (97<3%). These findings were supported by both the polyamine content, which consisted mainly of spermidine [12<9 lmol (g dry wt)N1], and the presence of 2-OH 14:0, 2-OH 15:0 and 2-OH 16:0 in the cellular fatty acid profile. DNA–DNA hybridization experiments resulted in similarity values of 31<9 % between strain W-50T an