Paper Title
Investigating the Parameters of Ultra-Sonication Method for Lipid Extraction Efficiency of Nannochloropsis SP. (PTCC 6016)

Abstract
Regarding the environmental consequences of using fossil fuels as the main source of energy, along with the depletion of these sources, enhances the priority of study on biofuels. Oil extracted from microalgae as a feedstock for biodiesel production is one of the promising options as this microorganism can treat wastewater, capture CO2 and its biomass can be used at other industries. Biodiesel production from microalgae has four stages (Fig. 1) after selecting the species: 1) Cultivation of the microalgae, 2) Harvesting the species from culture medium, 3) Oil extraction from algal biomass, 4) Biodiesel production from extracted oil. In this work, microalgae Nannochloropsis sp. (PTCC 6016) was cultivated in a 1000 L open raceway pond. Finally, the biomass harvested and lipid extracted by ultra-sonication method. Lipid extraction efficiency of dry biomass of PTCC 6016 with chloroform-methanol solvent was carried out and the effect of amount of biomass to solvent, ratio of solvents, time of experiment, ultrasound power and frequency cycles of transmitted ultrasound investigated. This was observed that at the ratio of 2:1 (methanol-chloroform), the extraction efficiency becomes maximum. Also, increasing the amount of biomass for a specific amount of solvent, reduces efficiency. Keywords - Biofuel Production, Lipid Extraction, Nannochloropsis sp.