Anaeroglomus insulsum gen. nov., sp. nov., anaerobic planctomycete, isolated from a thermal water stream.

A novel obligately anaerobic bacterium (strain U12dextrT) was isolated from sediment of a thermal water stream formed by discharge of artesian groundwater (Navoiy Region, Uzbekistan). The cells of the isolate were non-motile cocci, 0.5 to 0.8 μm in diameter forming chains or aggregates. The cells had a Gram-negative cell wall and divided by binary fission. The temperature range for growth was 37-47 °C (optimum at 42 °C). The pH range for growth was 5.5-7.5, with an optimum at pH 6.0-6.5. NaCl inhibited growth of strain U12dextrT at concentration of 1% and higher. The new isolate fermented mono-, di- and polysaccharides (dextran, xanthan gum, N-acetylglucosamine), but did not utilize proteinaceous compounds. Major cellular fatty acids were C20:0, i-C16:0, i-C14:0, and ai-C15:0. The genome of strain U12dextrT had a size of 3.4 Mb with a G + C content of 51.67%. Genome analysis revealed a large pool of CAZyme genes. The closest cultured phylogenetic relatives of strain U12dextrT was Anaerohalosphaera lusitana (phylum Planctomycetota) with 16S rRNA gene sequence similarity 90.6%. We propose to assign strain U12dextrT to a novel genus and species, Anaeroglomus insulsum gen. nov., sp. nov.; the type strain is U12dextrT (=VKM B-3770T = CGMCC 1.18105T = UQM 41804T). It is the first non-halophilic representative of the family Anaerohalosphaeraceae.