Table 2.
Lipids extracted from microalgae by MAE as a pre-treatment method.
| Microalgal Strain | Dry/Wet Method | Solvents Used | Ratio (Solvent to Sample) | Volumes Added | Microwave Settings | Product & Yield | Energy Use (MJ/kg) | Ref. |
|---|---|---|---|---|---|---|---|---|
| Crypthecodinium cohnii | Dry | Hexane | 18:1 | 2 g of milled algal powder, 35 mL hexane | 2.45 GHz, 45 °C, 30 min | 17.8% oil yield | x | [12] |
| Botryococcus sp. | Dry | Chloroform:methanol (1:1) | 200:1 | 0.5 g of algae powder, 100 mL distilled water, 100 mL chloroform:methanol | 2.45 GHz, 100 °C, 5 min | 28.1% lipid | x | [31] |
| Chlorella vulgaris | 10% lipid | |||||||
| Scenedesmus sp. | 10.4% lipid | |||||||
| Scenedesmus obliquus | Wet | Hexane | 1:1 | Equal volume of hexane to sample after heating | 2.45 GHz, 1200 W, 95 °C, 30 min (5 min intervals) | 31.38% wet weight (77% recoverable oil) | x | [47] |
| Chlorella sp. | Dry | Chloroform:methanol (1:1) | 400:1 | 0.5 g algae, 200 mL chloroform:methanol | 2.45 GHz, 100 °C, 5 min | 26 mg/g FAMEs | x | [63] |
| Nostoc sp. | 19 mg/g FAMEs | |||||||
| Tolypothrix sp. | 21 mg/g FAMEs | |||||||
| Chlorella vulgaris | Wet | Chloroform:methanol (1:1) | x | 500 mL culture pelleted | 2.45 GHz, 100 °C, 5 min | 18.14% lipid | x | [26] |
| Chlorella vulgaris | x | Chloroform:methanol (1:1) | 100:1 | 1 g algae, 100 mL chloroform:methanol | 300 W, 50 °C, 30 min | 31.9% DW lipid | x | [60] |
| Chlorella vulgaris SAG 211-12 | Dry | Chloroform:methanol (1:1) | 100:1 | 0.5 g algae, 50 mL distilled water, 50 mL chloroform:methanol | 2.45 GHz, 1000 W, 2.5 min | 9.59% DW lipid | x | [64] |
| Chlorogleopsis fritcschii | Dry | Dichloromethane | 25:1 | 1 g algae, 10 mL deionised water, 25 mL dichloromethane | 1200 W, 140 °C, 15 min | 1.4% DW lipid | x | [28] |
| Nannochloropsis oculata | 11.3% DW lipid | |||||||
| Pseudochoricystis ellipsoidea | 37.5% DW lipid | |||||||
| Chlorella PY-ZU1 GM | Wet | Chloroform:methanol (1:1) | 50:1 | 50 mL algal culture (1 g DW), 50 mL chloroform:methanol | 80 °C, 10 min | 18.7% DW lipid | 25.2 | [58] |
| Nannochloropsis sp. | Wet | Chloroform:ethanol (1:2) | 45:1 | 3.3 g wet algal paste, 50 mL chloroform, 100 mL ethanol, 40 mL deionised water | 2.45 GHz, 1200 W, 120 °C, 50 min (5 min ramp, 15 min hold, 30 min cool-down) | 53% DW lipid | x | [61] |
| 40% methyl soyate in ethanol | x | 3.3 g wet algal paste, 40% methyl soyate in ethanol | 56.6% DW lipid | |||||
| Phaeodactylum tricornutum | Wet | Chloroform | x | 45 mL culture pelleted, 5 mL distilled water, 3 mL chloroform | 2.45 GHz, 1000 W, level 4, 90 °C, 5 min | 32% (w/w) glycerides | x | [65] |
| Chlorella vulgaris | 21% (w/w) glycerides | |||||||
| Chlamydomonas reinhardtii | 7% (w/w) glycerides | |||||||
| Scenedesmus dimorphus | Wet | Chloroform:methanol (1:1) | 40:1 | 200 mg wet algae, 8 mL solvent | 557 W, 1 min then 254 W, 4 min | 17.2% DW lipid | x | [23] |
| Selanastrum minutum | 21% DW lipid | |||||||
| Chlorella protothecoides | 17% DW lipid | |||||||
| Nannochloropsis gaditana | Dry | Methanol | x | 5 g algae | 2.45 GHz, 30–35 W, 90 °C, 10 min | 14.82% DW FAs; 1.18% DW EPA | 10.9 Wh/g FA | [66] |
| Unknown microalga | Dry | n-heptane:isopropanol (2:1) | x | 5 g algae | 1000 W, 40 min | 28% DW lipid | x | [67] |
| Mixed culture of microalgae | Dry | Methanol:chloroform (1:1) | 10:1 | 500 mg algae, 2.5 mL methanol, 2.5 mL chloroform, 1.25 mL 1.5% sodium sulphate, 1 mL deionised water | 400 W, 100 °C, 5 min 30 s (70 s temperature ramp, 45 s hold, 3 cycles) | 33.7% DW lipid | x | [68] |
| Isochrysis sp. | Dry | Methanol:chloroform (1:2) | x | 0.5 g algae, 50 mL distilled water | 2.45 GHz, 1200 W, 45 °C, 30 MPa, 5 min | 7.8% DW FFAs; 0.08% DW EPA | x | [69] |
| Nannochloropsis gaditana | 10.8% DW FFAs; 0.47% DW EPA | |||||||
| Scenedesmus almeriensis | 3.1% DW FFAs; 0.22% DW EPA | |||||||
| Tetraselmis sp. | 4.8% DW FFAs; 0.1% DW EPA | |||||||
| Scenedesmus sp. | Dry | Chloroform:ethanol (1:1) | 20:1 | 40 mL mixture chloroform:ethanol, 2 g DW algae | 1000 W, 100 °C, 10 min | 53% lipid | 1.18 | [39] |
| Chlorella sp. | Dry | Ethanol | 12:1 | 4 g algae, 48 mL ethanol and 2% NaOH catalyst | 700 W (50% power), 75–80 °C, 6 min | 20.1% DW FAMEs | x | [70] |
| Dunaliella tertiolecta | Dry | Chloroform:methanol (2:1) | 100:1 | 0.2 g algae, 20 mL chloroform:ethanol | 490 W, 2 min 40 s | 57.02% lipid recovery | x | [71] |
| 160 W, 7 min | 56.98% lipid recovery | |||||||
| Nannochloropsis salina | Wet | n-hexane (added after microwave extraction) | 3:1 | 60 mL algal culture, 15 mL n-hexane (biomass loading 25%) | 1400 W, 205 °C, 25 min, 21.5 bar | 24.3% DW FAMEs; 1.65% DW EPA | 9.89 | [57] |
| Nannochloropsis sp. (BMRI) | Wet | Methanol:hexane (1:2) | x | 10 mL algal culture | 2.45 GHz, 1000 W (70% of power), 65 °C, 1 bar, 5 min | 38.31% DW lipid | x | [72] |
| Nannochloropsis oculata | Wet | Ethanol:hexane (3:1) (added after microwaving) | 23:1 | 4.3 g algae (1 g dry algae equivalent), 17 mL ethanol, 8 mL distilled water, 5.6 mL hexane | 2.45 GHz, 1025 W (100% power), 5 min (15 s heating bursts and cooled for 15 min) | 5.2% DW lipid | 140.78 | [21] |
| Scenedesmus obliquus | Dry | Chloroform:methanol (2:1) | 20:1 | 1 g algae, 20 mL chloroform:methanol | 1000 W, 100 °C, 10 min | 21.43% DW lipid | x | [73] |
| Stigeoclonium sp.; Monoraphidium sp.; Nitzschia sp. & Navicula sp. | Wet | x | x | 150 mL algal biomass | 2.45 GHz, 900 W, 3 min | 5 mg/L FAMEs | 34.3 | [29] |
| Arthrospira platensis | Dry | Methanol:ethyl acetate:light petroleum (1:1:1) | 17:1 | 20 g powder (milled with mortar and pestle) | 400 W, 70 °C, 1 bar, 15 min | 1.59% DW FAs | x | [74] |
| Chlorella vulgaris | Dry | Chloroform:methanol (1:1) | 7:1 | 5 g algae | 700 W, 50 s (10 s on, 30 s off cycle) | 31.7% DW lipid | 2.39 Wh/g | [75] |
| Chlorella sorokiniana | Dry | x | 10:1 | 1 g algae, 5 g hydrogen sulphate ionic liquid, 2% HCl | 800 W, 120 °C, 60 min | 27% DW lipid | x | [62] |
| Nannochloropsis salina | 14% DW lipid | |||||||
| Galdieria sulphuraria | 1 g algae, 5 g hydrogen sulphate ionic liquid | 22% DW lipid | ||||||
| Scenedesmus obliquus FR751179.1 | Dry | Chloroform:methanol (2:1) | 20:1 | 1 g algae, 20 mL chloroform:methanol | 1000 W, 100 °C, 10 min | 16.53% DW lipid | x | [76] |
| Scenedesmus obliquus | Dry | Chloroform:methanol (1:1) | 20:1 | 1 g algae, 20 mL chloroform:methanol | 1000 W, 100 °C, 10 min | 19.25% DW lipid | x | [56] |
| Wet | Chloroform:ethanol (1:1) | 10.08% DW lipid | ||||||
| Chlorella sp. | Wet | x | x | 15 g/L dewatered cells (15 mL distilled water), protonic ionic liquid (10:1 ratio to sample) | 700 W, 3 min | 3.5% DW lipid (cell disruption 74.75%) | x | [30] |
| Chlorococcum sp. | 0.803% DW lipid (cell disruption 70.03%) |
x stands for no information available or provided in the research papers surveyed.