roseobacter denitrificans roseobacter denitrificans roseobacter denitrificans is a species of aerobic pink-pigmented bacteria. it contains bacteriochlorophyll a. it contains spheroidenone, does not synthesize bacteriochlorophyll anaerobically, but shows aerobic phototrophic activity. cells are ovoid or rod-shaped and motile by subpolar flagella. r. litoralis does not reduce nitrate, while r. denitrificans does. roseobacter denitrificans scientific classification domain: bacteria phylum: pseudomonadota class: alphaproteobacteria order: rhodobacterales family: rhodobacteraceae genus: roseobacter species: r. denitrificans binomial name roseobacter denitrificansshiba, 1991