Paenibacillus thermotolerans sp. nov., isolated from a hot spring in Yunnan Province, south-west China

Two Gram-positive, rod-shaped, endospore-forming strains, YIM B05601 and YIM B05602^T, were isolated from soil sampled at Hamazui hot spring, Tengchong City, Yunnan Province, PR China. Phylogenetic analysis based on 16S rRNA gene sequences suggested that the two strains fell within the genus Paenibacillus, appearing most closely related to Paenibacillus alkalitolerans YIM B00362^T (96.9 % sequence similarity). Genome-based phylogenetic analysis confirmed that strains YIM B05601 and YIM B05602^T formed a distinct phylogenetic cluster within the genus Paenibacillus. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values of strains YIM B05601 and YIM B05602^T with the related species P. alkalitolerans YIM B00362^T were within the ranges of 74.43-74.57 % and 12.1-18.5 %, respectively, which clearly indicated that strains YIM B05601, YIM B05602^T represented a novel species. Strains YIM B05601 and YIM B05602^T exhibited 99.6 % 16S rRNA gene sequence similarity. The ANI and dDDH values between the two strains were 99.8 and 100 %, respectively, suggesting that they belong to the same species. Optimum growth for both strains occurred at pH 7.0 and 45 °C. The diagnostic diamino acid in the cell-wall peptidoglycan of strains YIM B05601 and YIM B05602^T was meso-diaminopimelic acid. MK-7 was the predominant menaquinone. The polar lipids of strain YIM B05602^T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, four unidentified glycolipids, an unidentified polarlipid and phosphatidylinositol mannoside. The major fatty acids of the two stains were iso-C_{15 : 0} and anteiso-C_{15 : 0}. Based on phylogenomic and phylogenetic analyses coupled with phenotypic and chemotaxonomic characterizations, strains YIM B05601 and YIM B05602^T could be classified as a novel species of the genus Paenibacillus, for which the name Paenibacillus thermotolerans sp. nov. is proposed. The type strain is YIM B05602^T (=CGMCC 1.60051^T=KCTC 43460^T=NBRC 115924^T).