Non-toxic proteins and omega-3 from algae and method of making same
Disclosed is a non-toxic omega-3 rich extract and non-toxic miscella and a method of producing same. The method may include obtaining an aqueous microalgae slurry comprising at least 65% water; mixing the aqueous microalgae slurry with ethanol for a predetermined duration; separating the aqueous microalgae slurry-ethanol mixture to liquids and miscella; and evaporating the water and the ethanol from the liquid to receive a liquid extract. In some embodiments, the miscella contains organic material and ash at an amount below 15 dry weight %.
1. A method of producing non-toxic proteins and omega- 3 from microalgae, the method consisting of:
obtaining an aqueous microalgae slurry comprising at least 65% water;
mixing the aqueous microalgae slurry with ethanol for a predetermined duration, to yield an aqueous microalgae slurry-ethanol mixture, wherein the ethanol diffuses into the cell structure of the microalgae and extracts nutritive elements from the microalgae cells through the cell membranes without disrupting the cell membranes of the microalgae;
separating the aqueous microalgae slurry-ethanol mixture, which includes the extracted nutritive elements, to liquids and miscella; and
evaporating the water and the ethanol from the liquid to receive a liquid extract,
wherein the miscella contains organic material and ash at an amount below 15 dry weight %.
2. The method of claim 1 , wherein the liquid extract contains omega-3 fatty acids.
3. The method of claim 1 , wherein the liquid extract contains more than 20 wt. % omega-3 fatty acids.
4. The method of claim 1 , wherein microalgae included in the aqueous microalgae slurry contain less than 6 wt. % omega-3 fatty acids and the method further comprises purifying the liquid extract with a solvent to reach a liquid extract that contains more than 20 wt. % omega-3 fatty acids.
5. The method of claim 1 , wherein the miscella contains at least 50 wt. % proteins.
6. The method of claim 1 , wherein a volume ratio between the ethanol and the aqueous microalgae slurry is at least 5:1.
7. The method of claim 1 , wherein the evaporating of the water and the ethanol comprises providing heat under vacuum to first evaporate the ethanol and then the water.
8. The method of claim 7 , wherein the heat is provided from thermal waste streams.
9. The method of claim 7 , wherein the heat is provided at a temperature range of 55° C.-65° C.
10. The method of claim 7 , wherein the vacuum is provided at 75-125 mbar.