ABSTRACT: 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 new isolate was an obligate anaerobe growing in prereduced medium only. The new isolate grew on the 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%), 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 where it is not closely related to representatives of any validly published names of genera. The nearest genera were Ammonifex and Caldanaerobacter with no more than 89.2% of identity. On the basis of its phylogenetic position and new phenotypic features, the isolate Kam1851T (= DSM 22653T = VKM B2685T) is proposed to be assigned to a new genus and species Brockia lithotrophica.
INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY 04/2012; · 2.11 Impact Factor