Enhancement of lipid extraction for efficient methyl ester production from Chlamydomonas sp.

The process development of microalgae oil extraction was optimized in the present study. The ultrasound was used to disrupt the isolated Chlamydomonas sp. cells. Among the various solvents tested, hexane showed the maximum extraction efficiency. Other extraction parameters such as solvent/algae ratio, temperature, and stirring speed were also optimized and found to be 6:1, 55 °C, and 300 rpm respectively. The extraction kinetics showed a first-order mechanism. After evaluation of thermodynamic parameters, the kinetics were found to be irreversible, endothermic, and spontaneous. The extracted oil was transesterified by stepwise and in situ methods and both methods showed similar results. Energy consumption is very similar for both stepwise and in situ transesterification. The methyl ester was characterized by thermogravimetric analysis (TGA) and the fuel properties were satisfactory when compared with the ASTM standard values. From the results, it is clear that the Chlamydomonas sp. under optimal lipid extraction conditions is a potential feedstock for the production of methyl ester.