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

## TL;DR

A new cold-loving bacterium, Cryobacterium inferilacus, was discovered in Antarctica's Lake Untersee and characterized based on its genetic and physical traits.

## Contribution

The discovery and classification of a novel psychrophilic species, Cryobacterium inferilacus, within the genus Cryobacterium.

## Key findings

- Strain 1639T grows optimally at 10°C and uses urea as a nitrogen source.
- Phylogenetic analysis shows high 16S rRNA similarity to other Cryobacterium species but distinct genomic differences.
- Genomic and phenotypic data confirm it as a new species within the Cryobacterium genus.

## Abstract

The psychrophilic aerobic heterotrophic bacterium, strain 1639T, 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-C16:0 (49.69%), ai-C15:0 (17.59%), and C16:1 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 1639T was a member of the genus Cryobacterium, with the highest sequence similarity to C. arcticum SK1T (98.4%), C. soli GCJ02T (98.4%), C. lactosi Sr59T (98.3%), C. zongtaii TMN-42T (98.2%), and C. adonitolivorans RHLS22-1T (98.1%). The ANI and the DNA–DNA hybridization estimate values between strain 1639T 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 1639T represents a novel species within the genus Cryobacterium, for which the name Cryobacterium inferilacus sp. nov. is proposed with the type strain 1639T (=KCTC 59142T, =VKM Ac-2907T, UQM 41460T).