Production of biofuels from the green alga Tetraselmis

The research described in thesis deals with the production of biofuels and fine chemicals from the green alga Tetraselmis suecica. Firstly, the identity of the strain received from the culture collection was confirmed using molecular techniques (18S rDNA sequencing) and electron microscopy. Secondly, a fully defined artificial seawater medium was developed to grow T. suecica and then the tolerance of this alga to salinity and pH changes was established. The neutral lipid (triacylglycerol) production was measured using Nile Red dye after stressing T. suecica cells with high salinity (up to 1 M NaCl) and pH values (pH 7 to 9). It was established that high salinity and high pH values tended to induce higher levels of triacylglycerol in the algal cells. Then fatty acid profiles of T. suecica cells were analyzed by gas chromatography–mass spectrometry (GC-MS) after direct transesterification with hydrochloric acid in methanol. Higher salinity grown cells showed higher levels of monounsaturated fatty acids, which are ideal for biodiesel production. The possibility of growing T. suecica on a larger scale was investigated using a 2 L airlift photobioreactor and the response to higher levels of CO2 was assessed in the airlift bioreactor. The effect of reusing the medium on the growth of T. suecica was examined with the aim of developing anintegrated algal biorefinery process using T. suecica as the feedstock.