Aquisphaera giovannonii gen. nov., sp. nov., a planctomycete isolated from a freshwater aquarium

Abstract

As part of a study of the diversity of planctomycetes, two novel strains, designated OJF2T and OJF8, were isolated from the sediments of a freshwater aquarium. The organisms were chemoheterotrophic, spherical and pink-pigmented, had an optimum growth temperature of about 30–35 °C and an optimum pH for growth of around 7.5–8.5. The predominant fatty acids were C18 : 1ω9c and C16 : 0. The two strains were able to assimilate several sugars and organic acids. 16S rRNA gene sequence analysis confirmed the affiliation of these organisms to the phylum ‘Planctomycetes’; they showed highest similarity to the type strains of Singulisphaera acidiphila (92.4 %) and Isosphaera pallida (91.9 %). On the basis of physiological, biochemical and chemotaxonomic characteristics, strains OJF2T and OJF8 are considered to represent a novel species of a new genus of the order Planctomycetales, for which the name Aquisphaera giovannonii gen. nov., sp. nov. is proposed. The type strain of Aquisphaera giovannonii is OJF2T ( = CECT 7510T  = DSM 22561T).