Solventless extraction process

• US 7,351,558 B2
• Filed: 02/20/2004
• Issued: 04/01/2008
• 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: Adu-peasah, Swithin Patrick, Ruecker, Craig M., Veeder, George T. III, Engelhardt, Brian S.
• Primary Examiner(s): Davis; Ruth A
• Application Number:
  US10/784,148
• Publication Number:
  US 20040229325A1
• Time in Patent Office: 1,502 Days
• Field of Search: 424/283.1, 435/41, 435/134, 435/173.4, 435/243
• 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 lipids from microorganisms comprising:

a) growing said microorganisms in a fermentation medium to produce a fermentation broth;

b) contacting said fermentation broth with a base to dissolve at least a part of any proteins present in said fermentation broth;

c) increasing the temperature of said fermentation broth to at least about 50°

C. to lyse cells of said microorganisms to produce a lysed cell mixture;

d) separating substances of different densities from said lysed cell mixture to produce a phase separated mixture comprising a heavy layer and a light layer wherein said heavy layer comprises an aqueous solution and said light layer comprises emulsified lipids;

e) removing said heavy layer from said phase separated mixture;

f) adding an aqueous washing solution to said light layer to form a further mixture;

g) separating substances of different densities from said mixture of step (f) to produce an additional phase separated mixture comprising an additional heavy layer and an additional light layer;

h) removing said additional heavy layer from said additional phase separated mixture; and

i) repeating said steps (f)-(h) until said lipid becomes substantially non-emulsified;

whereby lipids are obtained from microorganisms.

2. The process of claim 1, wherein said base is selected from the group consisting of hydroxides, carbonates, bicarbonates, and mixtures thereof.

3. The process of claim 1, wherein said step of producing the phase separated mixture comprises centrifuging said lysed cell mixture.

4. The process of claim 1, wherein the aqueous solution of step (d) comprises solid cell materials.

5. The process of claim 1, wherein the microorganisms are capable of growth at salinity level of less than about 12 g/L of sodium chloride.

6. The process of claim 1, wherein the microorganisms comprise at least about 30% by weight of lipid.

7. The process of claim 1, wherein the microorganisms are selected from the group consisting of algae, fungi, bacteria and protist.

8. The process of claim 7, wherein the microorganisms comprise microorganisms of the order Thraustochytriales.

9. The process of claim 8, wherein the microorganisms are selected from the genus Thraustochytrium, Schizochytrium and mixtures thereof.

10. The process of claim 9, wherein the 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.

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

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

13. The process of claim 1, wherein step (b) is conducted without drying the microorganisms.

14. A process for obtaining lipids from microorganisms comprising:

a) growing said microorganisms in a fermentation medium to produce a fermentation broth;

b) contacting said fermentation broth with a base to dissolve at least a part of any proteins present in said fermentation broth;

c) increasing the temperature of said fermentation broth to at least about 75°

C. to lyse cells of said microorganisms to produce a lysed cell mixture;

d) separating substances of different densities from said lysed cell mixture to produce a phase separated mixture comprising a heavy layer and a light layer wherein said heavy layer comprises an aqueous solution and said light layer comprises emulsified lipids.