Optimization of cell wall disruption and lipid extraction methods by
combining different solvents from wet microalgae
Abstract
Microalgae have emerged as one of the most promising options for
biodiesel production over the past few decades. Lipid extraction from
microalgae for biodiesel production as a bottleneck of biodiesel
production technology was the main purpose of this study. In this study
different methods of the cell wall disruption were compared. Then, two
methods of ultrasound and bead mill were used as methods of the cell
wall disruption. The maximum lipid extracted by ultrasound was 17.10%
and by bead mill was 15.16% (based on microalgae biomass dry weight).
After the cell wall disruption of microalgae, for lipid extraction,
chloroform-methanol solvent combination was used as a high extraction
method and hexane-ethanol solvent combination was used as an
environmentally friendly method. In this regard, the effect of solvent
to biomass ratio, temperature and extraction time was investigated and
the optimal results for chloroform-methanol solvent combination were 8
ml/g, 45°C and 60 minutes, respectively, and for hexane-ethanol
combination were 6 ml/g, 35◦C and 73 minutes, respectively. Under these
optimal conditions, the highest amount of extracted lipid from Chlorella
vulgaris with a moisture content of 87.50%, and ultrasound as a cell
wall disruption method were obtained 20.39% and 16.41% (based on
microalgae dry weight) with a combination of chloroform-methanol
solvents and hexane-ethanol respectively. Also the highest extraction
rates of 17.63% and 13.85% were obtained for the combination of
chloroform-methanol and hexane-ethanol solvents, respectively by bead
milling as cell wall disruption method