Sphingomonas starnbergensis sp. nov., isolated from a prealpine freshwater lake

Abstract

A novel type of freshwater bacterium was isolated from the prealpine mesotrophic Starnberger See (Bavaria, southern Germany). Cells of strain 382T were Gram-negative and rod-shaped, motile and creamy-white. The isolate was strictly aerobic, catalase- and oxidase-positive, and grew at pH values of 6–9 (optimum, pH 7) and temperatures of 10–37 °C (optimum, 28 °C). The genomic G+C content of strain 382T was 64.1 mol%. Based on 16S rRNA gene sequence analyses, strain 382T belongs to the family Sphingomonadaceae and clusters within the genus Sphingomonas . Sphingomonas histidinilytica UM 2T and Sphingomonas wittichii DSM 6014T were the closest relatives, as indicated by the highest 16S rRNA gene sequence similarities (97.1 % and 96.8 %, respectively). Sphingomonas paucimobilis DSM 1098T (the type species of the genus Sphingomonas ) exhibited 95.3 % sequence similarity. This affiliation of strain 382T to the genus Sphingomonas is confirmed by the presence of Q-10 as the major respiratory quinone, two sphingoglycolipids, C14 : 0 2-OH as the major 2-hydroxy fatty acid and sym-homospermidine as the major polyamine. The main cellular fatty acids of strain 382T were C18 : 1ω7c (39 %), C16 : 1ω7c (21 %), C16 : 0 (10 %) and C14 : 0 2-OH (10 %). Based on the phylogenetic distance from other species of the genus Sphingomonas and its unusually high C16 : 1ω7c content, strain 382T represents a novel species of the genus Sphingomonas , for which the name Sphingomonas starnbergensis is proposed. The type strain is 382T ( = DSM 25077T  = LMG 26763T).