Thauera hydrothermalis sp. nov., a thermophilic bacterium isolated from hot spring.

A Gram-stain-negative, non-spore-forming, rod-shaped, motile bacterial strain, designated GD-2, was isolated from a sediment sample collected from a hot spring in the Tibet Autonomous Region, China. Strain GD-2 grew at a temperature range of 37-55 °C (optimum, 45-50 °C), a pH range of 5.5-11.0 (pH 7.0-7.5) and a NaCl concentration range of 0-4.0 % (0 %). The phylogenetic analysis based on 16S rRNA gene sequencing showed that strain GD-2 represented a member of the genus Thauera within the family Zoogloeaceae. Strain GD-2 was closely related to Thauera linaloolentis 47Lol with the highest 16S rRNA gene sequence similarity of 95.5 %. The whole genomic average nucleotide identity value for GD-2 and 47Lol was 75.3 %. The predominant cellular fatty acids of the strain were C16 : 0, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C10 : 0 3-OH and C12 : 0. The main polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified phospholipids and two unidentified aminolipids. The major isoprenoid quinone was ubiquinone 8. Genome sequencing revealed that the genome size of GD-2 was 3 059 321 bp with a G+C content of 63.57 mol%. On the basis of phylogenetic, phenotypic and chemotaxonomic characteristics, strain GD-2 is considered to represent a novel species of the genus Thauera, for which the name Thauera hydrothermalis sp. nov. is proposed. The type strain is GD-2 (=NBRC 112472=CGMCC 1.15527).