A novel moderately halophilic, Gram-stain negative and aerobic bacterium, designated strain TBZ21T, was isolated from a water sample of Urmia Lake, Iran. Cells were observed to be non-motile rods with no flagellum, showing positive catalase and oxidase reactions. Strain TBZ21T was found to grow at 10-40 °C (optimum, 30 °C), at pH 7-10 (optimum, pH 8) and in the presence of 1-22% (optimum, 10%). The major fatty acids were identified as C19:0 cyclo ω8c, C16:0, Summed features 3 (C13:0 3-OH and/or iso-C15:1 H) and 8 (C18:1 ω7c and/or C18:1 ω6c) and C12:0 3-OH. The major polar lipids were identified as diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and an unidentified phosphoaminolipid. The genomic DNA G+C content of strain TBZ21T was determined to be 63.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain TBZ21T belongs to the genus Halomonas, and shows high sequence similarities to Halomonas fontilapidosi 5CRT (99.43%), Halomonas ventosae AL12T (98.64%), Halomonas sediminicola CPS11T (98.63%) and Halomonas aestuarii Hb3T (98.08%), and has low similarities (below 98.0%) with other members of the genus. The values of DNA-DNA relatedness between strain TBZ21T and the closely related strains H. fontilapidosi LMG 24455T and H. ventosae LMG 26187T were 42 ± 11% and 54 ± 16%, respectively. On the basis of phenotypic, chemotaxonomic and molecular characteristics, strain TBZ21T is concluded to represent a novel species of the genus Halomonas, for which the name Halomonas tabrizica sp. nov. is proposed. The type strain is TBZ21T (=LMG 25445T=DSM 23018T).
Keywords: Halomonas tabrizica; Novel species; Polyphasic taxonomy; Urmia Lake.