CAROTENOIDS FROM THE AEROBIC PHOTOSYNTHETIC BACTERIUM, ERYTHROBACTER-LONGUS - BETA-CAROTENE AND ITS HYDROXYL DERIVATIVES

About 20 different carotenoids were found in a strictly aerobic photosynthetic bacterium, Erythrobacter longus. All the carotenoids except the highly polar ones were identified as C40-skeletal carotenoids, which could be devided into three groups: (1) bicyclic carotenoids: β-carotene and its hydroxyl derivatives; β-cryptoxanthin, zeaxanthin, caloxanthin and nostoxanthin, (2) monocyclic carotenoids: rubixanthin, bacteriorubixanthin and bacteriorubixanthinal, which was a unique cross-conjugated carotenal, and (3) acyclic carotenoids: anhydrorhodovibrin and spirilloxanthin. Bacteriorubixanthinal and zeaxanthin were the major components. (3 R)-3-Hydroxy-β-ionone has rarely been found in carotenoids of purple photosynthetic bacteria, while the acyclic carotenoids have been found exclusively in photosynthetic bacteria. Thus, this bacterium is interesting in its composition of carotenoids. © 1990 Springer-Verlag.