Effect of glycerol on carotenogenesis in the extreme halophile, Halobacterium cutirubrum

Growth of cells of Halobacterium cutirubrum in complex medium in the presence of 0.1 to 0.5% glycerol was slightly stimulated (about 10%), but the content of the major red pigment, bacterioruberin, was reduced fourfold and that of the minor red pigments, mono- and bisanhydrobacterioruberins, was also reduced but to a lesser extent. The content of the C40 carotenes, beta-carotene and lycopene, however, was greatly increased in 0.1 to 0.5% glycerol but was then reduced to negligible amounts at higher glycerol concentrations (1 to 5%). Similar effects of glycerol on carotenogenesis were observed when cells were grown in a chemically defined medium (BSMK), but growth of cells was considerably slower.