Caldovatus sediminis gen. nov., sp. nov., a moderately thermophilic bacterium isolated from a hot spring.

Abstract

A Gram-stain-negative, ovoid-shaped, aerobic, non-motile, catalase- and oxidase-positive, and moderately thermophilic bacterial strain, designated strain YIM 72346T, was isolated from a sediment sample collected from a hot spring in Tengchong county, Yunnan province, south-west China. Growth occurred at 37-50 °C (optimum, 45 °C), at pH 6.0-9.0 (optimum, pH 6.5-7.0) and in the presence of 0.5-1.0 % (w/v) NaCl (optimum, 0.5 %). The major cellular fatty acids were C18 : 1ω7c, C16 : 0, C19 : 0cyclo ω8c,and C18 : 1 2-OH. The genomic DNA G+C content was determined to be 69.8 mol%. The predominant ubiquinone was Q-10. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified aminolipid and two unidentified phospholipids. Bacteriochlorophyll α and carotenoic acids were not detected. Strain YIM 72346T was not observed for the accumulation of poly-β-hydroxybutyrate. The strain shared highest 16S rRNA gene sequence identities with Crenalkalicoccus roseus YIM 78023T (93.3 %) and Craurococcus roseus NS130T (92.7 %), but formed a distinct lineage within the family Acetobacteraceae in the phylogenetic trees. On the basis of genotypic, phenotypic, chemotaxonomic and phylogenetic analyses, strain YIM 72346T is considered to represent a novel genus and species of the family Acetobacteraceae, for which the name Caldovatus sediminis gen. nov., sp. nov. is proposed. The type strain of Caldovatus sediminis is YIM 72346T (=KCTC 52714T=CGMCC 1.16330T).