Extraction of neutral lipids by a two solvent method

• US 8,273,248 B1
• Filed: 06/18/2012
• Issued: 09/25/2012
• Est. Priority Date: 04/06/2010
• Status: Expired due to Fees

• Current Assignee: Heliae Development, LLC (PT Perusahaan Perkebunan London Sumatra Indonesia Tbk)
• Original Assignee: Heliae Development, LLC (PT Perusahaan Perkebunan London Sumatra Indonesia Tbk)
• Inventors: Kale, Aniket
• Primary Examiner(s): DRODGE, JOSEPH W
• Application Number:
  US13/526,408
• Publication Number:
  US 20120255906A1
• Time in Patent Office: 99 Days
• Field of Search: 210/633, 210/634, 210/639, 210/650, 210/651, 210/703, 210/743, 210/749, 210/770, 210/774, 210/787, 210/804, 210/806, 435/134, 435/262, 435/267, 435/271, 435/272, 443/07, 443/08, 446/05, 47/14, 554/12, 554/14, 554/20, 208/15, 208/49, 208/87, 208/133, 208/142, 203/28, 203/39, 203/91, 203/DIG.21, 203/DIG.25, 560/218, 562/600
• US Class Current: 210/634
• CPC Class Codes: B01D 11/0492 Applications, solvents used
• CPC Class Codes: C02F 1/001 Processes for the treatment of water whereby the filtration technique is of importance C02F1/44 takes precedence; construction of filters in general B01D24/00 - B01D41/00
• CPC Class Codes: C02F 1/24 by flotation C02F1/465 takes precedence
• CPC Class Codes: C02F 1/38 by centrifugal separation
• CPC Class Codes: C02F 1/40 Devices for separating or removing fatty or oily substances or similar floating material cleaning or keeping clear the surface of open water from oil or like materials E02B15/04; devices in sewers for separating liquid or solid substances from sewage E03F5/14, e.g. for use in drains leading to the sewer E03F5/16
• CPC Class Codes: C02F 9/00 Multistage treatment of water, waste water or sewage
• CPC Class Codes: C10L 1/1802 natural products, e.g. waxes, extracts, fatty oils
• CPC Class Codes: C11B 1/10 by extracting
• CPC Class Codes: C11B 1/102 in counter-current; utilisation of an equipment wherein the material is conveyed by a screw
• CPC Class Codes: C11B 1/108 after-treatment, e.g. of miscellae
• CPC Class Codes: C12P 7/6463 obtained from glyceride producing microorganisms, e.g. single cell oil

Abstract

A method for separating neutral lipids from plant material, in particular, intact algal cells, using an amphipathic solvent set and a hydrophobic solvent set. Some embodiments include dewatering intact algal cells and then extracting neutral lipids from the algal cells. The methods provide for single and multistep extraction processes which allow for efficient separation of algal neutral lipids from a wet algal biomass while avoiding emulsification of extraction mixtures. The neutral lipids are removed after first removing a polar lipid fraction and a protein fraction. These neutral lipids can be used to generate renewable fuels as well as food products and supplements.

Claims

1. A method of separating neutral lipids from intact algal cells, comprising:

providing a wet algal biomass comprising intact algal cells which comprise proteins, polar lipids and neutral lipids;

dewatering the wet algal biomass by removing extracellular water to increase the solid content of the wet algal biomass to between 5% and 50% to generate a partially dewatered wet algal biomass;

mixing the partially dewatered wet algal biomass with a first amphipathic solvent set and a first hydrophobic solvent set to generate a first extraction mixture comprising a first heavier phase and a first lighter phase, wherein the first heavier phase comprises the first amphipathic solvent set, neutral lipids, proteins, and partially dewatered wet algal biomass and the first lighter phase comprises the first hydrophobic solvent set and the polar lipids;

separating the first lighter phase of the extraction mixture from the first heavier phase of the extraction mixture;

separating the partially dewatered wet algal biomass from the first amphipathic solvent set in the first heavier phase of the extraction mixture to generate a separated partially dewatered wet algal biomass comprising neutral lipids; and

a protein mixture comprising proteins, water and the first amphipathic solvent set;

mixing the separated partially dewatered algal biomass with a second amphipathic solvent set and a second hydrophobic solvent set to generate a second extraction mixture comprising a second heavier phase and a second lighter phase, wherein the second heavier phase comprises the second amphipathic solvent set and separated partially dewatered wet algal biomass and the second lighter phase comprises the second hydrophobic solvent set and the neutral lipids;

separating the second heavier phase from the second lighter phase; and

separating the neutral lipids from the second lighter phase.

2. The method of claim 1 wherein the dewatering of the wet algal biomass includes centrifuging, filtering, settling or float fractionating.

3. The method of claim 1 wherein at least one of the first and second amphipathic solvent set is acetone, methanol, ethanol, isopropanol, butanone, dimethyl ether, and propionaldehyde. 2-propanol, acetonitrile, t-butyl alcohol, 1-propanol, water, heavy (D₂O), ethylene glycol, glycerin or a combination thereof.

4. The method of claim 1 wherein at least one of the first and second hydrophobic solvent set is propane, butane, pentane, butene, propene, naphtha, an alkane, hexane, pentane, heptane, octane, an ester, ethyl acetate, butyl acetate, a ketone, methyl ethyl ketone, methyl isobutyl ketone, an aromatic, toluene, benzene, cyclohexane, tetrahydrofuran, a haloalkane, chloroform, trichloroethylene, an ether, diethyl ether, diesel, jet fuel, gasoline and mixtures thereof.

5. The method of claim 1 wherein the second heavier phase is separated from the second lighter phase by decanting, membrane filtration or centrifugation.

6. The method of claim 1 wherein the second lighter phase is heated prior to separating the neutral lipids from the second lighter phase.

7. The method of claim 1 wherein the second hydrophobic solvent set is removed from the second lighter phase by evaporation or distillation, thereby generating a neutral lipid fraction.

8. The method of claim 1 wherein at least one of the first and second amphipathic solvent set is evaporated.

9. The method of claim 1 wherein at least one of the first and second hydrophobic solvent set is recovered.

10. The method of claim 1 wherein at least one of the first and second hydrophobic solvent set is chilled and recovered.

11. The method of claim 1 wherein at least one of the first and second amphipathic solvent set is chilled and recovered.

12. The method of claim 1 wherein at least one of the first and second amphipathic solvent set is recovered.

13. The method of claim 1 wherein at least one of the first and second extraction mixture is heated.

14. The method of claim 13 wherein at least one of the first and second extraction mixture is heated with microwaves, water, steam, or hot oil or electricity.

15. The method of claim 13 wherein at least one of the first and second extraction mixture is heated at atmospheric pressure.

16. The method of claim 13 wherein at least one of the first and second extraction mixture is heated in a pressurized reactor.

17. The method of claim 16 wherein the pressurized reactor is a batch or a continuous reactor.

18. A method of separating neutral lipids from intact algal cells, comprising:

providing a wet algal biomass comprising intact algal cells which comprise proteins, polar lipids and neutral lipids;

mixing the wet algal biomass with a first amphipathic solvent set and a first hydrophobic solvent set to generate a first extraction mixture comprising a first heavier phase and a first lighter phase, wherein the first heavier phase comprises the first amphipathic solvent set, neutral lipids, proteins, and wet algal biomass and the first lighter phase comprises the first hydrophobic solvent set and the polar lipids;

separating the first lighter phase of the extraction mixture from the first heavier phase of the extraction mixture;

separating the wet algal biomass from the first heavier phase of the extraction mixture to generate a separated wet algal biomass comprising neutral lipids; and

a protein mixture comprising proteins, water and the first amphipathic solvent set;

mixing the separated algal biomass with a second amphipathic solvent set and a second hydrophobic solvent set to generate a second extraction mixture comprising a second heavier phase and a second lighter phase, wherein the second heavier phase comprises the second amphipathic solvent set and separated wet algal biomass and the second lighter phase comprises the second hydrophobic solvent set and the neutral lipids;

separating the second heavier phase from the second lighter phase; and

separating the neutral lipids from the second lighter phase to generate a neutral lipids fraction.