Bacterial Carotenoids. XIV. The Carotenoids of Rhodomicrobium vannielii.

Abstract

The carotenoid composition of R. vannielii Duchow and Douglas, has been re-examined in a quantitative manner. It was possible to isolate all, except one, of the compounds of the so-called normal spirilloxanthin series. The distribution pattern thus indicates a pathway of biosynthesis of these carotenoids analogous to that established elsewhere. Rhodopin is the major carotenoid. The structure previously suggested for rhodopin (III) is supported by its NMR-spectrum. [beta]-Carotene constitutes a minor component, not invariably present. The taxonomic position of this organism, based partly on its content of [beta]-carotene, is evaluated. In addition, two dihydroxy-carotenoids were isolated in small amounts. The major one is a l,2,l[image],2[image]-tetrahydro-l,l[image]-dihydroxylycopene (IX).