R. vannielii contains carotenoid pigments, which gives its cultures a salmon-pink to a deep orange-red color, depending on the density of growth.
[6] Optimum carotenoid production was achieved after the culture spent 24 hours in GMM without yeast-extract and having been incubated in anaerobic-light condition at a light intensity of 2000 lux.
R. vannielii is an anoxygenic bacteria, meaning it uses light as an energy source and converts it into ATP without the production of oxygen as a byproduct of the reaction.
All inoculated bottles were incubated using 60 W (Morries) tungsten lamps at 2000 lux light intensity of continuous illumination with a temperature ranging between 38-40 °C.
On average, R. vannielii’s genome size is approximately 400 base pairs, is motile, stains Gram-negative, and has a G+C content of 62.2%.
[8] However, subsequent studies of the physiology and morphology of several pure R. vannielii cultures have led researchers to create a new genus for this organism: Rhodomicrobium.