Production and Characterization of Third-Generation Biodiesel from Microalgae Oil

Third-generation biodiesel, derived from microalgae, presents a sustainable alternative to fossil fuels with no compromise on food security or utilization of large areas of arable land. This study deals with the production of biodiesel from Chlorella vulgaris microalgae oil by using a two-stage process, acid-catalyzed esterification followed by base-catalyzed transesterification, and the characterization of the produced biodiesel. Acid esterification of crude oil with 0.8 wt% H2SO4 lowered the acid value to 0.46 mg KOH/g, thereby meeting the quality requirements for subsequent transesterification. A maximum yield of biodiesel of about 94.86% was obtained through base-catalyzed transesterification under the reaction parameter of 9:1 methanol to oil molar ratio, 1.2 wt% KOH, 55oC reaction temperature, and 120 minutes reaction time. Characterization of the produced biodiesel and raw oil was performed, measuring density, kinematic viscosity, calorific value, and acid value according to ASTM standards. Overall, it satisfies the international biodiesel specifications given by ASTM D6751 and EN 14214. The results brought out the immense potential of Chlorella vulgaris as one of the most promising feedstocks for high-yield biodiesel production in the quest for sustainable energy.