Aeromicrobium changchenzhani sp. nov. and Streptomyces changchenzhani sp. nov., two novel actinomycetes isolated from soils of Ardley Island, Fildes Peninsula, Antarctica

Two Gram-stain-positive, non-motile actinomycetes, designated Or2-10a T and 21So2-11 T , were isolated from ornithogenic and pristine soils collected on Ardley Island, Fildes Peninsula, King George Island, maritime Antarctica. 16S rRNA gene sequence analysis revealed that strains Or2-10a T and 21So2-11 T showed the highest similarities to Aeromicrobium panaciterrae Gsoil 161 T (98.02%) and Streptomyces drozdowiczii NRRL B-24297 T (97.85%), respectively. Phylogenetic analyses based on 16S rRNA gene sequences confirmed the close relationships of these strains. Genomic analyses further supported the novel taxonomic status of these two species based on average nucleotide identity and digital DNA–DNA hybridization. Strains Or2-10a T and 21So2-11 T contained MK-9 and MK-9 (H 8 ) as the predominant menaquinone, respectively. High abundances of C 18 : 1 ω 9 c and C 16 : 0 were detected in Or2-10a T , whereas iso-C 16 : 0 , anteiso-C 15 : 0 and iso-C 16 : 1 h were dominant in 21So2-11 T . The cell-wall peptidoglycan of both Or2-10a T and 21So2-11 T contained ʟʟ-diaminopimelic acid. The whole-cell sugars of the two strains contained ribose and strain Or2-10a T contained additional glucose. Strain Or2-10a T contained diphosphatidylglycerol (DPG), phosphatidylglycerol, phosphatidylinositol (PI), an unidentified phospholipid and an unidentified phosphoglycolipid as major polar lipids, whereas strain 21So2-11 T contained DPG, phosphatidylethanolamine, PI and phosphatidylinositol mannoside as major polar lipids. On the basis of polyphasic taxonomy analysis, strains Or2-10a T and 21So2-11 T are concluded to represent two novel species of the genera Aeromicrobium and Streptomyces , respectively. The names Aeromicrobium changchenzhani sp. nov. (type strain Or2-10a T =CCTCC AA 2025019 T = DSM 120837 T =KCTC 59632 T ) and Streptomyces changchenzhani sp. nov. (type strain 21So2-11 T = CCTCC AA 2024063 T = DSM 121692 T =JCM 38519 T ) are proposed.