The carotenoids of Flavobacterium strain R1560

Abstract
The main carotenoid of Flavobacterium strain R1560 has been identified as (3R,3′R)-zeaxanthin. Also present were small amounts of 15-cis-phytoene, phytofluene, “ζ-carotene” (7,8,7′,8′-tetrahydro-ψ, ψ-carotene plus 7,8,11,12-tetrahydro-ψ, ψ-carotene), neurosporene, lycopene, β-zeacarotene, γ-carotene, β-carotene, β-cryptoxanthin, rubixanthin, 3-hydroxy-β-zeacarotene and several apo-carotenals. Zeaxanthin production was inhibited by nicotine (10 mM), and lycopene and rubixanthin accumulated. The biosynthesis of zeaxanthin is discussed in terms of pathways and also of “half-molecule” reaction sequences. The presence of zeaxanthin may be a characteristic of a group of Flavobacterium species, and may thus be useful in the taxonomic classification of these organisms.