Chelatococcus sambhunathii sp. nov., a moderately thermophilic alphaproteobacterium isolated from hot spring sediment

Abstract

A moderately thermophilic bacterial strain (HT4T) isolated from a hot spring sediment was characterized phenotypically and phylogenetically. Cells were Gram-negative, aerobic, non-sporulating, rod-shaped and motile by means of a single polar flagellum. Both oxidase and catalase activities were positive. Heterotrophic growth was observed at pH 6.0–8.5 and at 20–50 °C; optimum growth occurred at pH 7.5–8.0 and 37–42 °C. The major cellular fatty acids were C14 : 0 3-OH, C18 : 0 3-OH, C18 : 1 2-OH, C18 : 1 ω7c and C19 : 0 cyclo ω8c. The DNA G+C content of strain HT4T was 67.8 mol%.16S rRNA gene sequence analysis indicated that strain HT4T clustered within the radiation of the genus Chelatococcus and showed 99.0 % similarity with Chelatococcus daeguensis CCUG 54519T and 96 % similarity with Chelatococcus asaccharovorans DSM 6462T. However, levels of DNA–DNA relatedness between strain HT4T and Chelatococcus daeguensis CCUG 54519T and Chelatococcus asaccharovorans DSM 6462T were 52 and 20 %, respectively. On the basis of the phenotypic, physiological and chemotaxonomic data, 16S rRNA gene sequence analysis and DNA–DNA hybridization results, strain HT4T is considered to represent a novel species of the genus Chelatococcus, for which the name Chelatococcus sambhunathii sp. nov. is proposed. The type strain is HT4T (=DSM 18167T=JCM 14988T).