Seawater samples were collected from various locations along the Lebanese coast. Four unilagal isolates were acquired using streaking and serial dilution methods. The four isolates were cultured in 20 L flat photo-bioreactors containing seawater fertilized with Guillards F/2 medium. The growth dynamics, dry matter yield, lipid content, fatty acid profile and potential biodiesel yield were determined. The lipid content varied among growth phases and was greatest in the stationary phase, where it ranged between 14.5% DW in the Jod isolate and 16.5% DW in Jbd isolate. The best microalgal isolate tested gave a biodiesel production of around 50mg/ L. Optimization of culture conditions to improve biodiesel yield and the search for better performing local phytoplankton species are in progress.