chromatium okenii chromatium okenii chromatium okenii is a gram-negative bacterium found in water. it belongs to the purple sulfur bacteria. these bacteria are capable of photosynthesis and use hydrogen sulfide (h2s) as an electron donor for co2 reduction and so do not produce oxygen. this type of photosynthesis is called anoxygenic photosynthesis. chromatium okenii is anaerobic and the cells are slightly curved or straight rods. chromatium okenii scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: chromatiales family: chromatiaceae genus: chromatium binomial name chromatium okenii(ehrenberg 1838) perty 1852 synonyms monas okenii ehrenberg 1838 rhabdomonas rosea cohn 1875 spirillum violaceum warming 1875 bacterium okenii (ehrenberg 1838) trevisan 1879 beggiatoa roseopersicina zopf 1883 rhabdochromatium roseum (cohn 1875) winogradsky 1888 rhabdochromatium fusiforme winogradsky 1888 bacillus okenii (ehrenberg 1838) trevisan 1889 mantegazzea winogradskyi trevisan 1889 mantegazzea rosea (cohn 1875) trevisan 1889 pseudomonas okenii (ehrenberg 1838) migula 1895 thiospirillum violaceum (warming 1875) migula 1900 chromatium densegranulatum skuja 1948