Cryobacterium Inferilacus sp. nov., a Pshychrophilic Ureolitic Bacterium From Lake Untersee in Antarctica

The psychrophilic aerobic heterotrophic bacterium, strain 1639^T, was isolated from the low-temperature Lake Untersee in Antarctica. The bacterium was Gram-positive, non-motile, yellow-green-pigmented, non-spore-forming, and a pleomorphic rod. Growth was observed at temperatures of 0-25 °C with an optimum at 10 °C. The strain used urea as a nitrogen source. The major fatty acids were i-C_16:0 (49.69%), ai-C_15:0 (17.59%), and C_16:1 branched (12.03%). Identified polar lipids were phosphatidylglycerols and a glycolipid. The respiratory quinone was determined to be MK-10. The genomic DNA G+C content was 68.03 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 1639^T was a member of the genus <i>Cryobacterium</i>, with the highest sequence similarity to <i>C. arcticum</i> SK1^T (98.4%), <i>C. soli</i> GCJ02^T (98.4%), <i>C. lactosi</i> Sr59^T (98.3%), <i>C. zongtaii</i> TMN-42^T (98.2%), and <i>C. adonitolivorans</i> RHLS22-1^T (98.1%). The ANI and the DNA-DNA hybridization estimate values between strain 1639^T and all type strains of species of the genus <i>Cryobacterium</i> were in the range of 84.3-87.8% and 20.5-40.3%, respectively. The combined genotypic and phenotypic data indicate that strain 1639^T represents a novel species within the genus <i>Cryobacterium</i>, for which the name <i>Cryobacterium inferilacus</i> sp. nov. is proposed with the type strain 1639^T (=KCTC 59142^T, =VKM Ac-2907^T, UQM 41460^T).