Carotenoids of Thiorhodaceae IV. The carotenoid composition of 25 pure isolates.

Abstract

The carotenoid composition of 25 pure isolates of Thiorhodaceae has been studied. The 17 carotenoids encountered can, on the basis of chemical and biochemical considerations, be grouped into the spirilloxanthin, okenone and warmingone series. Most of the isolates examined synthesize carotenoids belonging to one of these groups only—the so-called normal spirilloxanthin series being the most common. The distribution pattern of carotenoids in phototrophic bacteria in general is briefly discussed, and the implications of the carotenoid composition in the taxonomy of the sulphur purple bacteria are evaluated.