Liquid-Saturated Hydrocarbons Resulting from Pyrolysis of the Marine Coccolithophores Emiliania huxleyi and Gephyrocapsa oceanica

Abstract

: Two nanoplanktonic marine coccolithophores, Emiliania huxleyi and Gephyrocapsa oceanica, were grown at 23 degrees C with a 16-hour light and 8-hour darkness regimen. The cells were dried at room temperature and then subjected to pyrolysis at 100 degrees to 500 degrees C under anoxygenic conditions to produce hydrocarbons. Temperature-dependent profiles of the liquid-saturated hydrocarbons (saturates) produced during pyrolysis were very similar for the two strains, although the total amount was higher in E. huxleyi than in G. oceanica. The amount of saturates produced was only 0.05% to 0.15% below 200 degrees C, but about 2.1% to 2.8% at 300 degrees C. Their major components were normal alkanes in a series ranging from nC(11) to nC(35) with the predominant peak at nC(15). At 400 degrees and 500 degrees C most of saturates transformed into gaseous compounds. The major saturates identified in all pyrolysates were normal C(31) monounsaturated and diunsaturated alkenes, a series of normal alkanes, phytenes, C(28) sterenes, and steranes. Profiles of saturates in gas chromatography-mass spectroscopy varied with increasing pyrolysis temperature and also differed between E. huxleyi and G. oceanica. The two coccolithophores are useful candidates for the production of renewable liquid fuel through pyrolysis-especially E. huxleyi, which has higher production. The results also provide information for further studies on the characterization, source, and paleogeographic distribution of marine sediment.