Siphonobacter aquaeclarae gen. nov., sp. nov., a novel member of the family ‘Flexibacteraceae’, phylum Bacteroidetes

Abstract

A Gram-negative bacterium, designated P2T, was isolated from the biofilm developed on the inner surface of an ultrapure cooling water system in a Hungarian power plant and was characterized by a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain P2T was affiliated with the family ‘Flexibacteraceae’ in the phylum Bacteroidetes. Its closest relative was Flectobacillus lacus CL-GP79T (88.7 % 16S rRNA gene sequence similarity) followed by Arcicella rosea TW5T (86.5 %), Arcicella aquatica NO-502T (86.4 %), Flectobacillus roseus GFA-11T (86.3 %) and Flectobacillus major DSM 103T (85.4 %). Cells of strain P2T were facultatively anaerobic, non-motile rods. The major fatty acids were C16 : 1 ω5c (42.5 %), iso-C15 : 0 2-OH (17.2 %), iso-C17 : 0 3-OH (16.1 %) and iso-C15 : 0 (8.5 %). The major menaquinone was MK-7 and the predominant polar lipid was phosphatidylethanolamine. The DNA G+C content was 54.5 mol%. Thus, the phenotypic and genotypic analyses clearly showed that strain P2T is considerably different from members of other genera in the family ‘Flexibacteraceae’. Based on these results, it is concluded that strain P2T represents a novel species in a new genus, for which the name Siphonobacter aquaeclarae gen. nov., sp. nov. is proposed, with type strain P2T (=DSM 21668T =NCAIM B 02328T).