Gracilimonas mengyeensis sp. nov., a moderately halophilic bacterium isolated from a salt mine in Yunnan, south-western China

Abstract

A facultatively anaerobic, Gram-staining-negative, pale red-pigmented, non-motile, rod-shaped, moderately halophilic bacterium, designated strain YIM J14T, was isolated from a sediment sample from a salt mine in Yunnan, south-western China. Growth occurred at NaCl concentrations of between 2 % and 15 % (w/v) and optimally with 5–9 % NaCl. The optimum temperature and pH for growth of the strain were 28 °C and pH 7.5. The major cellular fatty acids were iso-C15 : 0, anteiso-C15 : 0 and iso-C17 : 1ω9c/10-methyl-C16 : 0. The polar lipid profile was composed predominantly of diphosphatidylglycerol, phosphatidylcholine and one unknown phospholipid. Minor amounts of other lipids were also detectable. The genomic DNA G+C content was 47.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequence comparisons indicated that strain YIM J14T was related to Gracilimonas tropica in the phylum Bacteroidetes . The level of 16S rRNA gene sequence similarity between strain YIM J14T and Gracilimonas tropica CL-CB462T was 96.9 %. A DNA–DNA hybridization experiment between strain YIM J14T and Gracilimonas tropica indicated levels of relatedness of 28 %. Chemotaxonomic data supported the placement of strain YIM J14T in the genus Gracilimonas . DNA–DNA hybridization and biochemical and physiological characterization allowed strain YIM J14T to be differentiated from Gracilimonas tropica . It is therefore considered to represent a novel species of the genus Gracilimonas , for which the name Gracilimonas mengyeensis sp. nov. is proposed. The type strain YIM J14T ( = ACCC 10717T = DSM 21985T).