SEPARATION OF BACTERIOCHLOROPHYLL HOMOLOGS FROM GREEN PHOTOSYNTHETIC SULFUR BACTERIA BY REVERSED-PHASE HPLC

A reversed-phase High Performance Liquid Cromatography (HPLC) method h as been developed to accurately separate bacteriochlorophylls c, d and e homologues in a reasonably short run time of 60 minutes. By using t his method, two well-defined groups of bacteriochlorophyll homologue p eaks can be discriminated. The first one consists of 4 peaks (min 24 t o 30), which corresponds to the four main farnesyl homologues. The sec ond peak subset is formed by a cluster of up to 10 minor peaks (min 33 to 40). These peaks can be related with series of several alcohol est ers of the different chlorosome chlorophylls. The number of homologues was, however, quite variable depending on both, the bacteriochlorophy ll and the bacterial species. The method hereby described, also provid es a good separation of other photosynthetic pigments, either bacteria l (Bacteriochlorophyll a, chlorobactene, isorenieratene and okenone) o r algal ones (Chlorophyll a, Pheophytin a and beta-carotene). A prelim inary screening of the homologue composition of several green photosyn thetic bacterial species and isolates, has revealed different relative quantitative patterns. These differences seem to be related to physio logical aspects rather than to taxonomic ones. The application of the method to the study of natural populations avoids the typical drawback s on the pigment identification of overlapping eukaryotic and prokaryo tic phototrophic microorganisms, giving further information about thei r physiological status.