Table 6.
Sequential extraction of microalgal lipids
| Cell-disruption method | Species | Cell-disruption condition | Extraction method | Production efficiency (mg/g cell) | Reference |
|---|---|---|---|---|---|
| Mechanical method | |||||
| Shear force | |||||
| Bead milling | Nannochloropsis oculate | Bead milling under 1750 bar pressure | Chloroform/ Methanol | 2.8 mglipid/g cell | Bharte and Desai (2021) |
| High-pressure homogenization | Chlorella saccharophila | Homogenization at 200 to 1000 bar | t-Butanol, Ammonium Sulfate | 400 mglipid/g cell | Mulchandani et al. (2015), Patel et al. (2018) |
| Nannochloropsis oculata | pH 6.0; homogenization at 125 MPa | Petroleum Ether | 200 mg lipid/g cell | Shene et al. (2016) | |
| Hydrodynamic cavitation | Nannochloropsis salina | Autoclave (5 kW); hydro cavitation (1.27 kW); ultrasonication (0.75 kW) | Hexane | 191.5 mg lipid/g cell | Lee and Han (2015) |
| Wave energy | |||||
| Ultra-sonication | Haematococcus pluvialis | Ultra-sonication in acetone | Hexane, Isopropanol | 19.8 mg lipid/g cell | Dong et al. (2016) |
| Microwave | Chlorella sp. | Time-20 min; MAS-II microwave reaction system for synthesis/extraction | Chloroform/ Methanol | 0.095 mg lipid/g cell | Cheng et al. (2015), Alhattab et al. (2019) |
| Electric force | |||||
| Pulsed electric field | Chlorella vulgaris | 25 kV/cm–100 μs; electrode distance 0.25 cm; electrode area 1.76 cm2; applied voltage 6.25 kV; applied current 55 A | Ethanol | 0.4 mg pigment/g cell | Luengo et al. (2015), Sati et al. (2019) |
| Heat | |||||
| Steam | Nannochloropsis oceanica | 0.1 s pressure release for 5 min; steam at set pressure 1.0 to 2.1 MPa | Hexane, Methanol, Ethanol, Isopropanol | 763 mg lipid/g cell | Cheng et al. (2015), Onumaegbu et al. (2018) |
| Hydrothermal liquefaction | Nannochloropsis oceanica | Time-60 min; 89 bar; Temp-350 °C, | Dichloromethane | 406 mg biocrude/g cell | Yoo et al. (2015), Patel et al. (2018) |
| Chemical method | |||||
| Acid | Chlorella vulgaris | 1% H2SO4 Temp-120 °C; Time-60 min | Hexane/Methanol, Chloroform/Methanol | 381.6 mg lipid/g cell | Park et al. (2014), Sati et al. (2019) |
| Osmotic shock | Chlamydomonas reinhardtii | NaCl or sorbitol 60 g/L | Chloroform/ Methanol | 33.4 mg lipid/g cell | Yoo et al. (2012) |
| Nanoparticle | Chlorella vulgaris | Time-96 h; NiO (< 50 nm), stirring at 80 rpm | Chloroform/Methanol | 900 mg lipid/g cell | Huang and Kim (2016) |
| Surfactant | Chlorella vulgaris | Temp-120 °C, Time-1 h; 0.2% sodium dodecyl benzene sulfonate; 2% H2SO4 | Hexane/Methanol | 843.9 mg lipid/g cell | Park et al. (2014), Alhattab et al. (2019) |
| Biological method | |||||
| Enzymatic lysis | Nannochloropsis oceanica | Lipase; cellulose; protease | Hexane | 31.92 mg lipid/g cell in g/L algal culture | Chen et al. (2016a, b), Bharte and Desai (2018) |
| Algicidal treatment | Chlorella vulgaris | Time-3 days; Co-culture with Flammeovirgayaeyamensis | Chloroform | 218 mg lipid/g cell | Chen et al. (2013) |