Serinibacter arcticus sp. nov., isolated from a thawing ancient ice wedge

A novel actinobacterium, strain K3-2 T , was isolated in pure culture from a thawing ancient ice wedge at Mammoth Mountain (Eastern Siberia, Russia). Colonies of strain K3-2 T were yellowish orange; cells had the fine structure typical of Gram-positive bacteria, were non-motile short rods and were non-spore-forming. Strain K3-2 T was mesophilic (optimum growth at 28 °С), but capable of growing at 4 °С. The cell-wall peptidoglycan of strain K3-2 T contained lysine (the diagnostic diamino acid), glutamic acid, alanine, ornithine, glycine and serine. The polar lipids were phosphatidylglycerol, lysophosphatidylserine, three unidentified phospholipids and glycolipids. The major fatty acids were anteiso-C 15 : 0 and C 16 : 0 . The only menaquinone detected was MK-8(H 4 ). 16S rRNA gene analysis indicated that strain K3-2 T belongs to the genus Serinibacter . The closest taxonomically described relatives were Serinibacter salmoneus Kis4-28 T and Serinibacter tropicus PS-14-7 T , with 97.20 and 97.20 % 16 s rRNA gene sequence similarity, respectively. The average nucleotide identity value of the whole genome sequence between strain K3-2 T and S. salmoneus Kis4-28 T was 78.9 %. DNA–DNA relatedness values between strain K3-2 T and S. salmoneus DSM 21801 T (=Kis4-28 T ) and S. tropicus VKPM Ac 2044 T (=PS-14-7 T ) were 41 and 47 %. Thus, strain K3-2 T represents a novel species of the genus Serinibacter for which the name Serinibacter arcticus sp. nov. is proposed. The type strain is K3-2 T (DSM 103859 T =VKM Ас−2719 T ).