Arthrobacter alpinus sp. nov., a psychrophilic bacterium isolated from alpine soil

An aerobic, Gram-reaction-positive, non-motile, psychrophilic bacterium, designated strain S6-3T, was isolated from alpine soil. The objective of this study was to characterize the taxonomic position of this strain within the genus Arthrobacter. Methodologically, cells were examined for their growth conditions, phylogenetic relationships were analyzed using 16S rRNA gene sequences, and chemical composition was assessed, including menaquinone and fatty acid profiles. The results demonstrated that strain S6-3T exhibited a rod–coccus growth cycle, produced yellow pigment, and grew at temperatures as low as 1°C. Phylogenetic analysis indicated that strain S6-3T is closely related to Arthrobacter psychrolactophilus and Arthrobacter stackebrandtii, with sequence similarities of 97.9% and 97.6%, respectively. The cell-wall peptidoglycan type was identified as A3a L-Lys–L-Thr–Ala3, and the major fatty acid was anteiso-C15:0. With a genomic DNA G+C content of 61.9 mol%, based on its phenotypic characteristics, phylogenetic analysis, and DNA–DNA relatedness, strain S6-3T is proposed as a new species, Arthrobacter alpinus sp. nov. The type strain is S6-3T (DSM 22274T CGMCC 1.8950T).