A novel thermophilic bacterium, strain Kam1851T, was isolated from a terrestrial hot spring of the Uzon Caldera, Kamchatka Peninsula, Russia. Cells of strain Kam1851T were spore-forming rods with a Gram-positive type of cell wall. Growth was observed between 46 and 78 °C, and pH 5.5–8.5. The optimal growth (doubling time, 6.0 h) was at 60–65 °C and pH 6.5. The isolate was an obligate anaerobe growing in pre-reduced medium only. It grew on mineral medium with molecular hydrogen or formate as electron donors, and elemental sulfur, thiosulfate or polysulfide as electron acceptors. The main cellular fatty acids were C16 : 0 (34.2 %), iso-C16 : 0 (18 %), C18 : 0 (12.8 %) and iso-C17 : 0 (11.1 %). The G+C content of the genomic DNA of strain Kam1851T was 63 mol%. 16S rRNA gene sequence analysis showed that strain Kam1851T belonged to the order
Thermoanaerobacterales
, but it was not closely related to representatives of any genera with validly published names. The most closely related strains, which had no more than 89.2 % sequence similarity, were members of the genera
Ammonifex
and
Caldanaerobacter
. On the basis of its phylogenetic position and novel phenotypic features, isolate Kam1851T is proposed to represent a novel species in a new genus, Brockia lithotrophica gen. nov., sp. nov.; the type strain of Brockia lithotrophica is Kam1851T ( = DSM 22653T = VKM B-2685T).
Characterization Of A Novel Hydrolytic Enzyme Producing Thermophilic Bacterium Isolated From The Hot Spring Of Azad Kashmir-Pakistan
