A Gram-stain-negative, aerobic bacterium, designated strain YIM 77409T, was isolated from the Niujie hot spring in the Eryuan county of Dali, Yunnan province, south-west China. Cells of the strain were rod-shaped and colonies were yellow and circular. The strain grew at pH 6.0-8.0 (optimum, pH 7.0) and 50-70°C (optimum, 60-65°C). The predominant menaquinone was MK-8 and the DNA G+C content was 66.4 mol%. Major fatty acids (>10 %) were iso-C15 : 0 and iso-C17 : 0.The polar lipids consisted of one aminophospholipid, one phospholipid and two glycolipids. 16S rRNA gene sequence analysis showed that strain YIM 77409T formed a cluster with Thermus scotoductus DSM 8553T, Thermus antranikianii DSM 12462T, Thermus caliditerrae YIM 77925T and Thermus tengchongensis YIM 77924T, with highest 16S rRNA gene sequence similarity to T. scotoductus DSM 8553T (97.57%). However, DNA-DNA hybridization indicated that strain YIM 77409T should be viewed as a representative of a novel species, as there was only 30.6 ± 1.6% reassociation with T. scotoductus DSM 8553T. On the basis of the morphological and chemotaxonomic characteristics, as well as the genotypic data, it is proposed that strain YIM 77409T represents a novel species of the genus Thermus, with the name Thermus amyloliquefaciens sp. nov. The type strain is YIM 77409T ( = DSM 25898T = KCTC 32024T).