CHARACTERIZATION OF BACTERIAL AND ALGAL PIGMENTS AND BREAKDOWN PRODUCTS BY HPLC IN MIXED FRESH-WATER PLANKTONIC POPULATIONS

In order to characterise bacterial and algal photopigments and derived compounds in mixed populations we tested two HPLC procedures modified from MANTOURA & LLEWELLYN 1983 (PI) and KRAAY et al. 1992 (PII) which differed in the polarity of solvents and columns. The same numbers of compounds were found in algal extracts with both procedures, however, with a better separation of algal carotenoids and the presence of chl orophyllide b with PII. In contrast, higher numbers of homologues and breakdown products were found with PI for bacterial pigments, and spir illoxanthin was found only with this procedure. The criteria of elutio n order differed according to the procedure. In all of our samples we regularly found compounds assigned to be bacteriochlorophyllides, bact eriophaeophytins and bacteriophaeophorbides derived from bacteriochlor ophylls a, c and d, some of them as yet unreported, and three unidenti fied carotenoids accompanying those usually found in Rhodospirillaceae .