Potential biodiesel production from mixed phytoplankton cultures collected off the Lebanese coast

Seawater samples were collected from the coastal area along the Lebanese coast. The samples were fertilized using Guillards F/2 medium and cultured in 2 L flasks. Out of five promising blooms, three were selected and cultured in 70 L cylinders and in 300 L raceway ponds under greenhouse conditions. A culture of Chlorella "marine" was used as reference. The growth dynamics were determined and dry matter yield, lipid content, fatty acid profile and potential biodiesel yield were determined. Dry matter production varied among blooms and ranged between 455 and 641 mg/L/harvest, with the cylinders giving a 23-33% greater productivity in terms of mg dry matter/L/day. The lipid content in blooms varied between 16 and 18% DM and reached about 19% in the Chlorella isolate. In race way ponds as well as in the cylinders, two of the natural blooms yielded biodiesel in proportions similar to the Chlorella reference isolate. The Saida bloom gave a biodiesel production of 5.2 mg/L/day in cylinders and the Nahr ElKalb (NK2) bloom 4.3 mg/L/day in raceway ponds.