The Thermomicrobia are a group of thermophilic green non-sulfur bacteria. Until 2004, they were classified as a distinct phylum. It has recently been proposed, on the basis of an analysis of genetic affiliations, that the Thermomicrobia should more properly be reclassified as a class belonging to the phylum chloroflexi. The bacteria Sphaerobacter thermophilus originally described as an Actinobacteria is now considered a Thermomicrobia.