The effect of cell disruption on the extraction of oil and protein from concentrated microalgae slurries

Excess of Water Enables Efficient Lipid Extraction from Wet Pulsed-Electric Field-Treated A. protothecoides Microalgae Using Immiscible Solvents

“…A consensus in the literature is that when extraction is performed with a solvent that is nonmiscible with water, i.e., a nonpolar solvent such as hexane or solvent of low polarity, a preliminary cell disruption step is required to disrupt the cell wall and therefore give solvents access to the lipids. − The results presented in this study demonstrate the invalidity of this dogma since high lipid extraction yields (>20% DW ) were achieved with hexane and heptane, without any obvious fracturing of the microalgae cell wall as shown in Figure . This strongly supports the hypothesis that lipid transport happens through the cell barrier.…”

“…Using those techniques, several authors have demonstrated a perfect correlation between lipid extraction yield and disruption rate. 11,13 However, those approaches are typically limited by the high energy demand associated with the disruption step, i.e., on average 3.5 MJ/kg DW 14 or 8.75 MJ/kg lipids (lipid content: 40% DW ), although some promising innovations such as autolytic incubation enable to reduce the specific energy needed. 15 Another problem associated with such strategies is that the disruption of biomass implies the generation of extremely small debris, which is hard to separate and can form extremely stable emulsions.…”

“…Examples of solvents that are tested for those approaches are hexane or heptane but not only. A consensus is that such a biphasic extraction needs a preliminary cell disruption step which liberates the lipids by destroying the cell wall and allows the solvent to contact them. − “Cell disruption” is intended for any approach that destroys the mechanical integrity of the cell and in particular the integrity of the cell wall. Commonly used technologies are high-pressure homogenization and bead milling.…”

“…Commonly used technologies are high-pressure homogenization and bead milling. Using those techniques, several authors have demonstrated a perfect correlation between lipid extraction yield and disruption rate. , However, those approaches are typically limited by the high energy demand associated with the disruption step, i.e., on average 3.5 MJ/kg DW or 8.75 MJ/kg lipids (lipid content: 40% DW ), although some promising innovations such as autolytic incubation enable to reduce the specific energy needed …”

Big Things, Small Packages: An Update on Microalgae as Sustainable Sources of Nutraceutical Peptides for Promoting Cardiovascular Health

“…Pre-treatment enhances cell disruption and protein yield in microalgae. [8] Mechanical techniques such as bead-milling, high-pressure homogenization and ultrasonication are typically used as pre-treatment techniques prior to protein extraction; . Amino acid composition of proteins in selected microalgae and chicken egg compared to the WHO/FAO recommended daily intakes (RDI) for a 70-kg adult human for essential amino acids with RDI > 0.0.…”