Comamonas testosteroni is a Gram-negative environmental bacterium capable of utilizing testosterone as a carbon source, and degrading other sterols such as ergosterol and estrogens.

C. testosteroni is studied for the ability of strains in this species to degrade diverse aromatic carbon compounds, including many xenobiotic waste pollutants, such as 4-chloronitrobenzene and 4-hydroxybenzoate.

[3] A number of strains of Comamonas, including C. testosteroni, have been shown to consume terephthalic acid, one of the components of PET plastic, as a sole carbon source.

[4] C. testosteroni was found to catabolize terephthalate, vanillate, and 4-hydroxybenzoate to a protocatechuate intermediate, which is then degraded by initiation of ring formation at the 4,5-meta position.

[5] Because of its ability to degrade aromatic pollutants with relevance to bioremediation, methods for genetic engineering in Comamonas have begun to be developed.