Lipids of Haloferax alexandrinus strain TMT: an extremely halophilic canthaxanthin-producing archaeon

Abstract The core lipids, polar and non polar lipids, of the novel canthaxanthin-producing archaeon, Haloferax alexandrinus strain TM T , were investigated using thin-layer chromatography (TLC), spectrophotometry, electron ionization-mass spectroscopy (EI-MS), fast atom bombardment mass spectrometry (FAB-MS), nuclear magnetic response spectrometry ( 13 C-NMR) and high performance liquid chromatography (HPLC). This archaeon appeared to contain diphytanyl diether lipids (C 20 -C 20 ) as core lipids. The major phospholipids were found to be phosphatidylglycero-phosphate-methyl ester (PGP-Me) and phosphatidylglycerol (PG), but no phosphatidylglycero-sulfate was detected. The strain contained two glycolipids, sulfated diglycosyl diether (S-DGD-1) and unsulfated diglycosyl diether (DGD). Analysis of the non polar lipids revealed the presence of β-carotene, 3-hydroxyechinenone, γ-carotene, cis -astaxanthin, lycopene, trisanhydro-bacterioruberin,monanhydro-bacterioruberin, bacterioruberin isomer, bacterioruberin and canthaxanthin. Although the polar lipids profile of Hfx. alexandrinus strain TM T was similar to those of other species of the genus Haloferax , the non polar lipid (carotenoids) profile was markedly different. Further experiments on the influence of NaCl concentration on the lipids composition of Hfx. alexandrinus strain TM T demonstrated the dependence of the proportion of each of bacterioruberin, β-carotene and canthaxanthin on the NaCl concentration in the growth media.