Methods of dewatering algae for extraction of algal products

• US 8,318,019 B2
• Filed: 05/18/2012
• Issued: 11/27/2012
• 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:
  US13/475,487
• Publication Number:
  US 20120264194A1
• Time in Patent Office: 193 Days
• Field of Search: 443/05, 443/07, 446/05, 47/14, 210/632, 210/634, 210/638, 210/639, 210/656, 210/749, 210/770, 210/774, 210/806, 210/805, 435/134, 435/262, 435/267, 435/271, 435/272, 554/12, 554/20, 554/21, 554/174, 554/175
• US Class Current: 210/634
• CPC Class Codes: A61P 7/00 Drugs for disorders of the blood or the extracellular fluid
• CPC Class Codes: B01D 11/04 of solutions which are liquid
• CPC Class Codes: C11B 1/10 by extracting
• CPC Class Codes: C11B 1/108 after-treatment, e.g. of miscellae
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

A method of dewatering algae and recycling water therefrom is presented. A method of dewatering a wet algal cell culture includes removing liquid from an algal cell culture to obtain a wet algal biomass having a lower liquid content than the algal cell culture. At least a portion of the liquid removed from the algal cell culture is recycled for use in a different algal cell culture. The method includes adding a water miscible solvent set to the wet algal biomass and waiting an amount of time to permit algal cells of the algal biomass to gather and isolating at least a portion of the gathered algal cells from at least a portion of the solvent set and liquid of the wet algal biomass so that a dewatered algal biomass is generated. The dewatered algal biomass can be used to generated algal products such as biofuels and nutraceuticals.

Claims

1. A method of dewatering and selectively separating products from a wet algal cell culture, comprised of intact algal cells and water, comprising:

a. removing a portion of the water from a wet algal cell culture to obtain a first wet algal biomass fraction having a lower water content than the algal cell culture, and a first liquid fraction comprising water, the algal cells of the first wet algal biomass fraction having a quantity of chlorophyll;

b. mixing a first water miscible solvent set, comprising one or more solvents, with the first wet algal biomass fraction to generate a first dewatering mixture comprised of a second liquid fraction comprising water and a second wet algal biomass fraction, wherein the second wet algal biomass fraction comprises intact algal cells, and the algal cells of the second algal biomass fraction contain about the same quantity of chlorophyll as the algal cells of the first wet algal biomass fraction, and the second wet algal biomass fraction has a lower water content than the wet algal cell culture;

c. separating the second liquid fraction from the second wet algal biomass fraction;

d. mixing a second water miscible solvent set, comprising one or more solvents, with the second wet algal biomass fraction to generate a second dewatering mixture comprised of a third liquid fraction comprising water and a third wet algal biomass fraction;

e. separating the third liquid fraction from the third wet algal biomass, wherein the third wet algal biomass has a lower water content than the second wet algal biomass and comprises intact algal cells;

f. combining a the third wet algal biomass with an amphiphilic solvent set, the solvent set comprising one or more amphiphilic solvents, to make a first extraction mixture, wherein the weight of the amphiphilic solvent set is about the same as the weight of the wet algal biomass;

g. separating the first extraction mixture into a first liquid extraction phase comprising proteins and a first residual solid phase;

h. combining the first residual solid phase with an amphiphilic solvent set to make a second extraction mixture, wherein the weight of the amphiphilic solvent set is about the same as the weight of the first residual solid phase;

i. separating the second extraction mixture into a second liquid extraction phase comprising polar lipids and a second residual solid phase;

j. combining the second residual solid phase with an amphiphilic solvent set to make a third extraction mixture, wherein the weight of the amphiphilic solvent set is about the same as the weight of the second residual solid phase;

k. separating the third extraction mixture into a third liquid extraction phase comprising neutral lipids and a third residual solid phase, wherein the first liquid extraction phase has a higher protein concentration than the second and third liquid extraction phases, the second liquid extraction phase has a higher polar lipids concentration than the first and third liquid extraction phases, and the third liquid phase has a higher neutral lipids concentration than the first and second liquid extraction phases.

2. The method of claim 1, further comprising heating at least one of the first, second, and third extraction mixtures to a temperature below the boiling point of the extraction mixture.

3. The method of claim 1, further comprising recovering a first extraction product from the first liquid phase.

4. The method of claim 1, further comprising recovering a second extraction product from the second liquid phase.

5. The method of claim 1, further comprising recovering a third extraction product from the third liquid phase.

6. The method of claim 1, wherein at least one of the first, second or third extraction mixtures is held under a pressure greater than or equal to atmospheric pressure for a period of time.

7. The method of claim 6, further comprising heating at least one of the first, second and third extraction mixtures to a temperature below the boiling point of the corresponding extraction mixture.

8. The method of claim 6, wherein the period of time is at least 45 minutes.

9. The method of claim 1, wherein at least one of the solvent sets comprises methanol, ethanol, isopropanol, acetone, ethyl acetate, acetonitrile, or any combinations thereof.

10. The method of claim 1, wherein the algal biomass is unfrozen.

11. The method of claim 1, further comprising adjusting the pH of the first extraction mixture to optimize protein extraction.

12. The method of claim 1, further comprising repeating the sequence of extraction, combining and separating steps at least one more time.

13. The method claim 1, wherein at least one of the first, second and third solvent sets comprises two water miscible or two water immiscible solvents.

14. The method of claim 1, wherein at least one of the first, second and third solvent sets comprises one or more water miscible solvents and one or more water immiscible solvents.

15. The method of claim 1, wherein the algal biomass is simultaneously at least partially dewatered while products are selectively extracted from the algal biomass.