Psychroflexus lacisalsi sp. nov., a moderate halophilic bacterium isolated from a hypersaline lake (Hunazoko-Ike) in Antarctica

A novel Gram-negative, aerobic, moderate halophilic, and psychrotolerant bacterium, designated as strain H7^T, was isolated from a hypersaline lake located in Skarvsnes, Antarctica. Cells were filaments with varying lengths. Coccoid bodies developed in old cultures. Growth occurred with 0.5–15% (w/v) NaCl (optimum, 5.8–7.0%), at pH 6.0–10.0 (optimum, pH 7.0–8.0), and at 10–28°C (optimum, 25°C). The strain had a G+C content of 34.9 mol%, which is within the range of 32–36 mol% reported for the genus Psychroflexus. Chemotaxonomic data (major respiratory quinone: MK-6; major fatty acids: aC_15:0, iC_16:0 3-OH, and aC_{15: 1} A) supported the classification of strain H7^T within the genus Psychroflexus. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain H7^T should be assigned to the genus Psychroflexus and has a homology with Psychroflexus salinarum (98.2%), P. sediminis (96.1%), P. torquis (95.2%), P. tropicus (95.8%), and P. gondwanense (92.2%). Strain H7 is not identified as P. salinarum because that DNA-DNA hybridization data were 8.5% between strain H7^T and P. salinarum. The combination of phylogenetic analysis, DNA-DNA hybridization data, phenotypic characteristics, and chemotaxonomic differences supported the view that strain H7^T represents a novel species of the genus Psychroflexus. The name Psychroflexus lacisalsi is proposed, and the type strain is H7^T (=JCM 16231^T =KACC 14089^T).