Chlorophyll d production in crushed algae in aqueous acetone

Abstract

We for the first time report on the Chl a to Chl d conversion in crushed algae, Synechocystis sp. PCC6803, Emiliania huxleyi, Gephyrocapsa oceanica, Isochrysis galbana, Helladosphaera cornifera, Pleurochrysis carterae, Chlorella vulgaris, Chlamydomonas acidophila, incubated in aqueous acetone at 303 K for 2 days, where no Chl a was added externally to the system. The highest conversion of Chl a into Chl d was observed in G. oceanica (ca. 1.1%). The conversion yield was lower, when other algae were used: S. sp. PCC6803 (ca. 0.4%), E. huxleyi (ca. 0.3%), C. vulgaris (ca. 0.2%), I. Galbana (ca. 0.1%), H. cornifera (ca. 0.1%), P. carterae (ca. 0.06%), C. acidophila (ca. 0.04%). The well-known degradation reactions of Chl a, namely, pheophytinization (Chl a → Phe a) and epimerization (Chl a → Chl a′), were also observed. We should pay enough attention to the fact that Chl d was not detected at all in the initial algae examined here. It is interesting to note that Chl d, Chl d′, Chl a′ and Phe a were also detected in processed alga food, Chlorella powder and dried laver. It is noteworthy that these artifacts function as key components in natural photosynthesis.