Sustainable production of high-quality biodiesel using hydrothermal liquefaction technique from a novel unicellular freshwater microalga: Euglena gracilis

The study was performed to produce bioenergy through extraction of highquality biofuel from one of the novel fresh water in-vitro propagated microalgae Euglena gracilis. The biofuel was extracted from wet biomass of algae using hydrothermal liquefaction (HTL) technique where 10% slurry of microalgae was catalytically (CoAlMo2O3 as catalyst) oxidized for 1 h under 350 °C temperature and 200 bar pressure. About 32% yield of biocrude was achieved from HTL of E. gracilis with 95% and 82% of deoxygenation (deO) and denitrogenation (deN), respectively. The lipid contents from biocrude were separated by phase separation and esterified for the evaluation of physicochemical parameters: Cetane number, density, aniline point, and moisture contents and viscosity were recorded as 50.86, 0.90 gcm-3, 101, 13%, 0.84 kgm-1s-1, respectively, which are in agreement with the international standards of biodiesel quality. Finally, the quality of obtained biodiesel was enhanced by blending with petrodiesel, where B5 (5% biodiesel + 95% petrodiesel), B20 (20% biodiesel + 95% petrodiesel), B50 (50% biodiesel + 50% petrodiesel) and B100 (100% biodiesel) were prepared and analyzed. B5 and B20 blends proved qualitatively better than B50 and B100 blends and could be used commercially.