Arthrobacter antioxidans sp. nov., a blue pigment-producing species isolated from Mount Everest

Bacteria in the genus Arthrobacter have been found in extreme environments, e.g. glaciers, brine and mural paintings. Here, we report the discovery of a novel pink-coloured bacterium, strain QL17^T, capable of producing an extracellular water-soluble blue pigment. The bacterium was isolated from the soil of the East Rongbuk Glacier of Mt. Everest, China. 16S rRNA gene sequence analysis showed that strain QL17^T was most closely related to the species Arthrobacter bussei KR32 ^T. However, compared to A.bussei KR32^T and the next closest relatives, the new species demonstrates considerable phylogenetic distance at the whole-genome level, with an average nucleotide identity of <85 % and inferred DNA-DNA hybridization of <30 %. Polyphasic taxonomy results support our conclusion that strain QL17^T represents a novel species of the genus Arthrobacter. Strain QL17^T had the highest tolerance to hydrogen peroxide at 400 mM. Whole-genome sequencing of strain QL17^T revealed the presence of numerous cold-adaptation, antioxidation and UV resistance-associated genes, which are related to adaptation to the extreme environment of Mt. Everest. Results of this study characterized a novel psychrotolerant Arthrobacter species, for which the name Arthrobacter antioxidans sp. nov. is proposed. The type strain is QL17^T (GDMCC 1.2948^T=JCM 35246^T).