Characterization and Hydrocarbon Degradation Potential of Variovorax sp. Strain N23 Isolated from the Antarctic Soil

Increasing pollution has significantly threatened the Antarctic ecosystem. The contamination of hydrocarbons has drawn a considerable amount of attention owing to their toxicity, recalcitrance, and persistence. Considering the Antarctic Treaty, only indigenous species are allowed to bioremediate the contaminated environment. However, the knowledge of the ecological role, physiology, function, and genomics of endemic hydrocarbon consumers is still limited. Here, we investigated the dynamics of phenanthrene-consuming communities derived from the Antarctic soil and found that Variovorax, Rhodocyclaceae, and Hydrogenophaga were differentiated in all the phenanthrene-consuming subcultures. We isolated a pure culture of the key hydrocarbon consumer Variovorax sp. strain N23. Moreover, the result of the polyphasic approach suggested that strain N23 represents a novel species of the genus Variovorax. In addition, the genomic characteristics of this strain revealed incomplete degradation pathways for diverse hydrocarbons. Overall, this study reveals the relatively weak hydrocarbon-degrading potential of the indigenous bacteria and suggests the need for more careful protection of the Antarctic ecosystem.