Rhodobacter sphaeroides is a kind of purple bacterium; a group of bacteria that can obtain energy through photosynthesis.

Its best growth conditions are anaerobic phototrophy (photoheterotrophic and photoautotrophic) and aerobic chemoheterotrophy in the absence of light.

Such a metabolic versatility has motivated the investigation of R. sphaeroides as a microbial cell factory for biotechnological applications.

The regulation of its photosynthetic machinery is of great interest to researchers, as R. sphaeroides has an intricate system for sensing O2 tensions.

Twenty sRNAs were experimentally identified in Rhodobacter spheroides, and the abundant ones were shown to be affected by singlet oxygen (1O2) exposure.

[8] A cluster of four homologous sRNAs called CcsR for conserved CCUCCUCCC motif stress-induced RNA has been shown to play a role in photo-oxidative stress resistance as well.

For example, decrease in oxygen tensions activates the synthesis of photosynthetic machinery (including photosystems, antenna complexes and pigments).

[3] Knowledge of the physiology of R. sphaeroides allowed the development of biotechnological processes for the production of some endogenous compounds.

Hydrogen evolution occurs via the activity of the enzyme nitrogenase,[21] whereas isoprenoids are synthesized naturally via the endogenous MEP pathway.