Pretreatment and kinetics of oil extraction from algae for biodiesel production

In this study, extraction of lipid from algal sp. Chlorella vulgaris is investigated based on Bligh and Dyer method employing methanol and chloroform on wet biomass. Optimization methodology was established on comparison of pretreatment methods as well as investigation of ultrasonication and stirrer parameters to enhance cell disruption. It was found that biomass with water/solid proportion (w/s = 5) operating temperature of 50 degrees C both for ultrasonication and shaking, 5 min ultrasonication with further 3 h of stirring with 200 rpm is the best set of parameters for breakdown of cell envelops, and using these parameters, total extraction of 22.07% was obtained. Kinetic study of breakdown was carried out with further full-factorial investigation of extraction (%) vs time and temperature. Using Arrhenius equation, activation energy of about 34.73 kJ/mol was obtained for this algal sp. with R-2 = 97.81%. Further analysis using analysis of variance showed that when using lower temperatures, sudden increase of extraction occurs in longer times, and vice versa, hence emphasizing the interaction thereof. It was also found that temperature plays the vital role among all examined parameters. (C) 2014 Curtin University of Technology and John Wiley & Sons, Ltd.