Homoserinimonas flava sp. nov., a novel carotenoid-producing actinobacterium isolated from saline lake sediment

An actinobacterial strain, designated TRA05-7 T , was isolated from a saline lake sediment in the Ngari Prefecture, Xizang Autonomous Region, China. The cells were Gram-stain-positive, aerobic and short-rod-shaped. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain TRA05-7 T was most closely related to members of the genus Homoserinimonas , with the highest sequence similarity to Homoserinimonas hongtaonis 194 T (98.48%). However, whole-genome phylogenetic analysis revealed a closer relationship with Homoserinimonas sedimenticola SYSU T00001 T , with the two strains forming a distinct cluster. The average nucleotide identity and digital DNA–DNA hybridization values between strain TRA05-7 T and H. sedimenticola were 77.3 and 20.7%, respectively. The genomic DNA G+C content was 65.7 mol%. Growth occurred at 4–40 °C (optimum 28 °C), pH 7–11 (optimum pH 7) and with 0–8% (w/v) NaCl (optimum 1%). The major menaquinones were MK-12, MK-11 and MK-13. Polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids and one unidentified lipid. The major cellular fatty acids were anteiso-C 15:0 , anteiso-C 17:0 and anteiso-C 15:0 . UV-Vis and HPLC analysis indicated that strain TRA05-7 T had the ability to produce carotenoids. Based on phylogenetic, genomic, phenotypic and chemotaxonomic analyses, strain TRA05-7 T represents a novel species of the genus Homoserinimonas , for which the name Homoserinimonas flava sp. nov. is proposed. The type strain is TRA05-7 T (=MCCC 1K10024 T =KCTC 59574 T ).