Prokaryotic hydrocarbon degraders

Hydrocarbons have been part of the biosphere for millions of years, and a diverse group of prokaryotes has evolved to use them as a source of carbon and energy. To date, all the formally defined genera are eubacterial, in 7 of the 24 major phyla currently recognized (Tree of Life, 2009); principally in the Actinobacteria, the Bacteroidetes, the Firmicutes, and the Proteobacteria. Some Cyanobacteria have been shown to degrade hydrocarbons on a limited scale, but whether this is of any ecological significance remains to be seen ? it is likely that all aerobic organisms show some basal metabolism of hydrocarbons by nonspecific oxygenases, and similar ?universal? metabolism may occur in anaerobes. More recently, some thermophilic, acidophilic methanotrophs from the phylum Verrucomicrobia have also been isolated (Chapter 26, Vol. 3, Part 1); we may expect more diversity as research proceeds. There have been publications indicating that halophilic archaea are significant hydrocarbon-degraders in some environments, but these have not yet been rigorously, or formally, described.