Pilot cultivation of the chlorophyte microalga Scenedesmus obliquus as a promising feedstock for biofuel

• Scenedesmus obliquus was cultivated in plastic bags in a semicontinuous culture for high biomass production.
• Different flocculants were used for harvesting of S. obliquus and the oil was chemically extracted.
• The residual algal biomass was used for feeding of Artemia.
• The annual productivity of EFA from S. obliquus would be nearly 5 times higher than Jatropha.
• The residual algal biomass increased survival and fresh weight of Artemia.

Scenedesmus obliquus was discussed by phycologists as a promising microalga for biofuel production based on its biomass and fatty acid productivity. In the present study, S. obliquus was pilot cultivated for large scale production in a semicontinuous culture for 3 months using polyethylene transparent bags. Cultivation of S. obliquus resulted in a maximum biomass productivity of 0.14 g L−1 d−1 and maximum esterified fatty acid productivity of 17.37 mg L−1 d−1 at light intensity of 130 μmol m−2 s−1. Using of different flocculants for biomass harvest showed maximum flocculation efficiency of 82% using 250 mg L−1 of NaOH for 2 h. Drying of the harvested biomass showed significant increase of esterified fatty acid content by 5 and 7% with respect to control at 75 and 100 °C, respectively. In addition, fatty acid profile and iodine number of S. obliquus oil meet biodiesel standard specifications which make the fatty acid of S. obliquus eligible for further research to be used as a feedstock for biofuel production. Furthermore, the present investigation showed that after oil extraction, the residual algal biomass increased survival and fresh weight of Artemia (brine shrimp) which confirms that the residual algal biomass can be significantly used as food additives for animal feeding.