Thermus javaensis sp. nov., a novel thermophilic bacterium isolated from litter of a geyser in Cisolok, West Java, Indonesia.

A thermophilic, yellow-pigmented bacterial strain, designated LT1-2-5T, 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 LT1-2-5T within the genus Thermus, showing highest similarities to Thermus thalpophilus SYSU G00506T (98.54%) and Thermus brockianus YS038T (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-C17:0, iso-C15:0, anteiso-C15:0 and anteiso-C17:0. The polar lipids detected were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and unidentified glycolipids. The major menaquinone was menaquinone-8. The genome size of strain LT1-2-5T 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 LT1-2-5T and T. thalpophilus SYSU G00506T 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 LT1-2-5T as a novel species of Thermus, for which the name Thermus javaensis sp. nov. is proposed. The type strain is LT1-2-5T (=UICC B-84T=CGMCC 1.61921T=KCTC 102310T).