By 2001, the genus included more than 20 species that were quite diverse in terms of their phylogenetic, ecological, and physiological properties. As a result, the Sphingomonas were subdivided into four genera: Sphingomonas, Sphingobium, Novosphingobium and Sphingopyxis.
These genera are commonly referred to collectively as "sphingomonads" . The sphingomonads are widely distributed in nature, having been isolated from many different land and water habitats, as well as from plant root systems, clinical specimens, and other sources.
Some of the sphingomonads (especially Sphingomonas paucimobilis) also play a role in human disease, primarily by causing a range of mostly nosocomial, non-life-threatening infections that typically are easily treated by antibiotic therapy. Due to their biodegradative and biosynthetic capabilities, sphingomonads have been utilised for a wide range of biotechnological applications, from bioremediation of environmental contaminants to production of extracellular polymers such as sphingans (eg. gellan, welan, and rhamsan) used extensively in the food and other industries. One strain, Sphingomonas sp. 2MPII, can degrade 2-methylphenanthrene
In May 2008, Daniel Burd, a 16 year old Canadian, won the Canada-Wide Science Fair in Ottawa after discovering that Sphingomonas can degrade over 40% of the weight of plastic bags (Polyethylene) in less than three months.