Tuwongella immobilis gen. nov., sp. nov., a novel non-motile bacterium within the phylum Planctomycetes

A gram-negative, budding, catalase negative, oxidase positive and non-motile bacterium (MBLW1(T)) with a complex endomembrane system has been isolated from a freshwater lake in southeast Queensland, Australia. Phylogeny based on 16S rRNA gene sequence analysis places the strain within the family Planctomycetaceae, related to Zavarzinella formosa (93.3 %), Telmatocola sphagniphila (93.3 %) and Gemmata obscuriglobus (91.9 %). Phenotypic and chemotaxonomic analysis demonstrates considerable differences to the type strains of the related genera. MBLW1(T) displays modest salt tolerance and grows optimally at pH values of 7.5-8.0 and at temperatures of 32-36 °C. Transmission electron microscopy analysis demonstrates the presence of a complex endomembrane system, however, without the typically condensed nucleoid structure found in related genera. The major fatty acids are 16 : 1 ω5c, 16 : 0 and 18 : 0. Based on discriminatory results from 16S rRNA gene sequence analysis, phenotypic, biochemical and chemotaxonomic analysis, MBLW1(T) should be considered as a new genus and species, for which the name Tuwongella immobilis gen. nov., sp. nov. is proposed. The type strain is MBLW1(T) (=CCUG 69661(T)=DSM 105045(T)).