Abstract: Emiliania huxleyi is a ubiquitous species with the largest biomass in marine planktonics. When cells of E. huxleyi were grown in ESM with additional 20 mmol/L HC03- , coccolith scales were formed on cell surface and the weight ratio of calcium carbonate fixed in coecoliths to organic substance in cells was about 2.47: 1. It was only about 0.05: 1 in cells grown in ESM without HCO3- addition, where no coccoliths were observed under scanning electron microscope, and the content of lipid reached 18.1% of dry. cell weight. It was demonstrated that the HCO3- concentration was the key factor to control the calcification on cell surface. Therefore, in addition to the pathway of photosynthesis for CO2 fixation, calcification on cell surface forming coccoliths is an alternative pathway for fixing dissolved inorganic carbon in E. huxleyi. Moreover, being rich in lipids, E. huxleyi cells produced high content of hydrocarbons including extractable organic matter, saturates and aromatics under pyrolysis at 300℃. Among those, the yield of saturates from E. huxleyi reached as high as 2.8%, 6-15 times that from other algae. All these suggest that E. huxleyi is a good experimental system for studies on the optimization of environment through carbon cycle and renewable energy in algal biomass.

Key words: Emiliania huxleyi, Coccoliths, HCO3- concentration, CO2 fixation, Hydrocarbons by pyrolysis