<i>Thermus javaensis</i> sp. nov., a novel thermophilic bacterium isolated from litter of a geyser in Cisolok, West Java, Indonesia
Abstract
A thermophilic, yellow-pigmented bacterial strain, designated LT1-2-5<sup>T</sup>, was isolated from litter in the Cisolok Geyser, West Java, Indonesia. This strain is Gram-stain-negative, aerobic and non-sporulating, with rod-shaped cells and short filaments. Phylogenetic analyses based on 16S rRNA gene sequences (1,446 bp) placed strain LT1-2-5<sup>T</sup> within the genus <i>Thermus</i>, showing highest similarities to <i>Thermus thalpophilus</i> SYSU G00506<sup>T</sup> (98.54%) and <i>Thermus brockianus</i> YS038<sup>T</sup> (98.34%). The strain exhibited optimal growth at 60-65 °C, pH 7.0-8.0 and ≤2.0% (w/v) sodium chloride (NaCl). Major cellular fatty acids (>10%) were iso-C<sub>17:0</sub>, iso-C<sub>15:0</sub>, anteiso-C<sub>15:0</sub> and anteiso-C<sub>17:0</sub>. The polar lipids detected were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and unidentified glycolipids. The major menaquinone was menaquinone-8. The genome size of strain LT1-2-5<sup>T</sup> was 2.41 Mbp, and the DNA G+C content was 66.8 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain LT1-2-5<sup>T</sup> and <i>T. thalpophilus</i> SYSU G00506<sup>T</sup> were 91.46% and 42.9%, respectively, both of which are below the established species cut-off value. Polyphasic taxonomy, including phylogenetic, genomic, phenotypic and chemotaxonomic analyses, confirmed the status of strain LT1-2-5<sup>T</sup> as a novel species of <i>Thermus</i>, for which the name <i>Thermus javaensis</i> sp. nov. is proposed. The type strain is LT1-2-5<sup>T</sup> (=UICC B-84<sup>T</sup>=CGMCC 1.61921<sup>T</sup>=KCTC 102310<sup>T</sup>).