Solventless extraction process

• US 6,750,048 B2
• Filed: 01/19/2001
• Issued: 06/15/2004
• Est. Priority Date: 01/19/2000
• Status: Expired due to Term

• Current Assignee: DSM IP Assets BV (DSM-Firmenich AG)
• Original Assignee: Martek Biosciences Corporation (DSM-Firmenich AG)
• Inventors: Ruecker, Craig M., Veeder, George T. III, Engelhardt, Brian S., Adu-peasah, Swithin Patrick
• Primary Examiner(s): Lankford, Jr., Leon B.
• Assistant Examiner(s): Davis, Ruth A.
• Application Number:
  US09/766,500
• Publication Number:
  US 20020001833A1
• Time in Patent Office: 1,243 Days
• Field of Search: 424/195.15, 424/195.16, 424/195.17, 424/780, 435/134, 435/170, 435/171, 435/173.9
• US Class Current: 435/134
• CPC Class Codes: C11B 1/02 Pretreatment
• CPC Class Codes: C11B 3/001 by a combination of two or more of the means hereafter
• CPC Class Codes: C11B 3/006 by extraction
• CPC Class Codes: C12N 1/06 Lysis of microorganisms
• CPC Class Codes: C12P 23/00 Preparation of compounds containing a cyclohexene ring having an unsaturated side chain containing at least ten carbon atoms bound by conjugated double bonds, e.g. carotenes containing heterorings C12P17/00
• CPC Class Codes: C12P 25/00 Preparation of compounds containing alloxazine or isoalloxazine nucleus, e.g. riboflavin
• CPC Class Codes: C12P 33/00 Preparation of steroids
• CPC Class Codes: C12P 7/6427 Polyunsaturated fatty acids [PUFA], i.e. having two or more double bonds in their backbone
• CPC Class Codes: C12P 7/6432 Eicosapentaenoic acids [EPA]
• CPC Class Codes: C12P 7/6434 Docosahexenoic acids [DHA]
• CPC Class Codes: C12P 7/6463 obtained from glyceride producing microorganisms, e.g. single cell oil
• CPC Class Codes: C12P 7/6472 containing polyunsaturated fatty acid [PUFA] residues, i.e. having two or more double bonds in their backbone

Abstract

The present invention provides a method for extracting lipids from microorganisms without using organic solvent as an extraction solvent. In particular, the present invention provides a method for extracting lipids from microorganisms by lysing cells and removing water soluble compound and/or materials by washing the lysed cell mixtures with aqueous washing solutions until a substantially non-emulsified lipid is obtained.

Claims

1. A process for obtaining lipid from microorganisms comprising:

a) lysing cells of the microorganisms to produce a lysed cell mixture;

b) treating said lysed cell mixture using an extraction process conducted in a medium that comprises less than about 5% of an organic solvent, while avoiding organic solvent extraction to obtain said lipid, wherein said process produces a phase separated mixture comprising a heavy layer and a light layer, wherein said heavy layer comprises an aqueous phase and said light layer comprises lipid, and wherein said step of treating comprises treating said lipid to obtain non-emulsified lipid in said light layer;

c) separating said heavy layer from said light layer; and

d) obtaining said lipid from said light layer.

2. The process of claim 1, wherein said step (b) comprises centrifuging said lysed cell mixture.

3. The process of claim 2, wherein said light layer comprises an emulsified lipid.

4. The process of claim 3 further comprising:

e) adding an aqueous extraction solution to said light layer of step (c); and

f) repeating said steps (b), (c) and (e) until said lipid becomes substantially non-emulsified prior to said step (d).

5. The process of claim 3, wherein said emulsified lipid comprises a suspension of said lipid in an aqueous phase.

6. The process of claim 1, wherein said aqueous phase comprises solid cell materials.

7. The process of claim 1, wherein said microorganisms are obtained from a fermentation process.

8. The process of claim 7 further comprising adding a base to a fermentation broth.

9. The process of claim 8, wherein said base is selected from the group consisting of hydroxides, carbonates, bicarbonates, and mixtures thereof.

10. The process of claim 7 further comprising solubilizing at least part of proteinaceous compounds in a fermentation broth.

11. The process of claim 1, wherein said step (a) comprises heating said microorganisms to temperature of at least about 50°

C.

12. The process of claim 1, wherein said microorganism is capable of growth at salinity level of less than about 12 g/L of sodium chloride.

13. The process of claim 1, wherein said microorganism comprises at least about 30% by weight of lipid.

14. The process of claim 1, wherein said microorganism is selected from the group consisting of algae, fungi, bacteria and protist.

15. The process of claim 14, wherein said microorganisms comprise microorganisms of the order Thraustochytriales.

16. The process of claim 15, wherein said microorganisms are selected from the genus Thraustochytrium, Schizochytrium and mixtures thereof.

17. The process of claim 16, wherein said microorganisms are selected from the group consisting of microorganisms having the identifying characteristics of ATCC number 20888, ATCC number 20889, ATCC number 20890, ATCC number 20891 and ATCC number 20892, mutant strains derived from any of the foregoing, and mixtures thereof.

18. The process of claim 1, wherein said microorganisms are capable of producing at least about 0.1 grams per liter per hour of docosahexaenoic acid.

19. The process of claim 1, wherein at least about 30% of said lipid is docosahexaenoic acid.

20. The process of claim 1, wherein said process is conducted in an aqueous phase and said aqueous phase comprises less than about 5% of an organic solvent.

21. The process of claim 1, wherein said process is conducted in an aqueous phase and said aqueous phase comprises less than about 4% of an organic solvent.

22. The process of claim 1, wherein said process is conducted in an aqueous phase and said aqueous phase comprises less than about 2% of an organic solvent.

23. The process of claim 1, wherein said process is conducted in an aqueous phase and said aqueous phase comprises less than about 1% of an organic solvent.

24. The process of claim 1, wherein said treating said lysed cell mixture of step (b) is conducted without drying said cell mixture prior to the extraction process.

25. The process of claim 1, wherein said process is conducted in the absence of an organic solvent.

26. The process of claim 1, wherein said process is conducted on microorganisms in a microbial biomass comprising at least about 10% by weight entrained water.

27. The process of claim 1, wherein said process is conducted on microorganisms in a microbial biomass comprising at least about 20% by weight entrained water.

28. The process of claim 1, wherein said process is conducted on microorganisms in a microbial biomass comprising at least about 30% by weight entrained water.

29. The process of claim 1, wherein said process is conducted on microorganisms in a microbial biomass comprising at least about 50% by weight entrained water.