Abstract
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 Cryobacterium, with the highest sequence similarity to C. arcticum SK1(T) (98.4%), C. soli GCJ02(T) (98.4%), C. lactosi Sr59(T) (98.3%), C. zongtaii TMN-42(T) (98.2%), and C. adonitolivorans 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 Cryobacterium 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 Cryobacterium, for which the name Cryobacterium inferilacus sp. nov. is proposed with the type strain 1639(T) (=KCTC 59142(T), =VKM Ac-2907(T), UQM 41460(T)).