Altererythrobacter lauratis sp. nov. and Altererythrobacter palmitatis sp. nov., isolated from a Tibetan hot spring

Abstract

Two Gram-negative, moderately thermophilic, yellow-pigmented, rod-shaped and motile bacterial strains, designated YIM 75003^T and YIM 75004^T, were isolated from sediment samples collected from the Tagejia hot spring in Tibet, western China. The taxonomic affiliation of the two strains was investigated by a polyphasic approach. Pairwise comparison of the 16S rRNA gene sequences showed that strains YIM 75003^T and YIM 75004^T are closely related to Altererythrobacter buctense M0322^T (97.2 and 97.1% respectively), while sharing 99.9% sequence similarity against each other. Optimum growth of the two strains was observed at 37-45 °C, pH 8.0 and in the presence of 1-6% NaCl (w/v). Their predominant respiratory quinone was found to be ubiquinone 10. The major fatty acids in both the strains were identified as summed feature 8 (C_18:1 ω6c and/or C_18:1 ω7c) and summed feature 4 (C_17:1 anteiso B and/or iso I). Their major polar lipid profiles were found to be diphosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol and sphingoglycolipid. The DNA G+C contents of strains YIM 75003^T and YIM 75004^T were determined to be 61.3 and 60.1 mol%, respectively. The DNA-DNA hybridization values between strains YIM 75003^T and YIM 75004^T, and between the two strains and their closely related phylogenetic neighbour A. buctense M0322^T (=CGMCC 1.12871^T) were less than 70%. Based on the morphological and physiological properties, phylogenetic analyses, chemotaxonomic characteristics and DNA-DNA relatedness values, the two strains can be distinguished from each other and from their phylogenetically closely related strain. Strains YIM 75003^T and YIM 75004^T are, therefore, considered to represent two novel species of the genus Altererythrobacter, for which the names Altererythrobacter lauratis sp. nov. (type strain YIM 75003^T = KCTC 52606^T = CCTCC AB2016268^T) and Altererythrobacter palmitatis sp. nov. (type strain YIM 75004^T = KCTC 52607^T = CCTCC AB2016270^T) are proposed.

Keywords: Altererythrobacter lauratis sp. nov.; Altererythrobacter palmitatis sp. nov.; Polyphasic taxonomy; Tagejia hot spring.