Arthrobacter

Arthrobacter is a genus of Gram-positive, aerobic, non-spore-forming bacteria in the phylum Actinobacteria. A hallmark of this genus is its pleomorphic life cycle: in the log phase cells are typically rod-shaped, and as they enter stationary phase they become coccoid. They are widely distributed in soil and freshwater and are commonly recovered from environmental samples.

Most Arthrobacter are non-motile and form pigmented colonies in some species, ranging from yellow to orange. They tolerate desiccation and can persist under nutrient-poor conditions, which contributes to their ubiquity in soil ecosystems.

Members of the genus are chemoorganotrophs that metabolize a broad range of organic compounds. They play a role in the decomposition of soil organic matter and can participate in biogeochemical cycles. Several strains are notable for degrading environmental pollutants, including aromatic compounds and pesticides; for example, Arthrobacter aurescens TC1 is known for atrazine degradation.

Notable species include Arthrobacter globiformis and Arthrobacter ureafaciens. The genus is studied for bioremediation, enzyme production, and biocatalysis, as well as for understanding microbial resilience in soils.

Although primarily environmental, Arthrobacter species are occasionally isolated from human clinical samples; infections are rare and usually occur in individuals with compromised immune systems.