Nesterenkonia maliinae sp. nov. and Arthrobacter arnarulunnguaqae sp. nov., two halotolerant, psychrotolerant and alkaliphilic actinobacteria isolated from Peary Land, Northern Greenland

Strains CF4.4^T and KK5.5^T, previously isolated from samples of biocrust and permafrost, respectively, collected from Northern Greenland, were characterized using a polyphasic approach. Both strains were Gram-stain-positive, non-motile and non-endospore-forming cocci, and showed growth between 4 and 25 °C and 0-20% (w/v) NaCl. Strain CF4.4^T showed growth at pH 6-11 [optimal growth at pH 9-10 and 5% (w/v) NaCl]. Its 16S rRNA gene sequence showed similarities over 99% with <i>Nesterenkonia jeogali</i> JG-241^T, <i>Nesterenkonia lutea</i> YIM 70081^T and <i>Nesterenkonia sandarakina</i> YIM 70009^T. Based on digital DNA-DNA hybridization, the closest type strain to strain CF4.4^T was <i>Nesterenkonia aurantiaca</i> DSM 27373^T (31.8% similarity). The major respiratory menaquinones of strain CF4.4^T were MK-7, MK-8, MK-9 and MK-10, and its major cellular fatty acids were anteiso-C_15:0, anteiso-C_17:0 and iso-C_16:0. Its cells contained diphosphatidylglycerol, phosphatidylglycerol, an unidentified glycolipid and an unidentified phospholipid. Strain KK5.5^T showed growth at pH 6-10, with optimal growth at pH 8-9 and 0-2.5% (w/v) NaCl. Phylogenetic analysis based on its 16S rRNA gene sequence showed that it was most closely related to <i>Arthrobacter halodurans</i> JSM 078085^T (99.1%), <i>Arthrobacter ginkgonis</i> SYP-A7299^T (97.7%) and <i>Zafaria cholistanensis</i> NCCP-1664^T (97.6%). The genome of strain KK5.5^T showed the most similarity to <i>A. halodurans</i> DSM 21081^T (22.6%) based on digital DNA-DNA hybridization. The major respiratory menaquinones of strain KK5.5^T were MK-9(H₂) and MK-10(H₂), with small amounts of MK-11(H₂). Its major cellular fatty acids were anteiso-C_15:0, anteiso-C_17:0 and iso-C_15:0, and its cells contained diphosphatidylglycerol, phosphatidylglycerol, two unidentified glycolipids and an unidentified phospholipid. Based on the results presented in this study, we conclude that both strains represent novel species, for which we propose the names <i>Nesterenkonia maliinae</i> sp. nov. (type strain CF4.4^T=DSM 120326^T=LMG 34127^T) and <i>Arthrobacter arnarulunnguaqae</i> sp. nov. (type strain KK5.5^T=DSM 120323^T=LMG 34129^T).