General Information: Cellulose-degrading bacterium. This genus contains two species: Rubrobacter radiotolerans and Rubrobacter xylanophilus. These two species represent the oldest lineage (deepest branch) of the Actinobacteria and are distantly related to Mycobacteria and Streptomycetes. Both species are thermophilic and exhibit high tolerance to radiation. Very little research has been done on these organisms and little is known other than their taxonomic characterization. Rubrobacter xylanophilus was isolated from a thermally polluted industrial runoff in the United Kingdom. Some strains of this species are capable of degrading hemicellulose and xylan (polymers of plant origin), and could play a significant role in the degradation of these compounds in the wood and paper industry as well as in the environment.