Comamonas is a genus of Gram-negative, rod-shaped, motile bacteria, with Comamonas terrigena as its type species. Some members accumulate poly-beta-hydroxybutyrate, the biodegradable storage polymer industry eyes as a bioplastic; others, such as C. acidovorans and C. testosteroni, produce biotechnologically useful enzymes including esterases and quinohaemoprotein alcohol dehydrogenases. Taxonomy has shuffled the genus: C. terrigena and C. testosteroni were once classified as Pseudomonas, while C. acidovorans is now considered synonymous with Delftia acidovorans. Environmental isolates, they turn up in soil, water, and occasionally clinical samples.