Structuring fats and methods of producing structuring fats
Recombinant DNA techniques are used to produce oleaginous recombinant cells that produce triglyceride oils having desired fatty acid profiles and regiospecific or stereospecific profiles. Genes manipulated include those encoding stearoyl-ACP desturase, delta 12 fatty acid desaturase, acyl-ACP thioesterase, ketoacyl-ACP synthase, and lysophosphatidic acid acyltransferase. The oil produced can have enhanced oxidative or thermal stability, or can be useful as a frying oil, shortening, roll-in shortening, tempering fat, cocoa butter replacement, as a lubricant, or as a feedstock for various chemical processes. The fatty acid profile can be enriched in midchain profiles or the oil can be enriched in triglycerides of the saturated-unsaturated-saturated type.
1. A recombinant cell of the genus Prototheca comprising at least 20% lipid by dry cell weight, wherein the cell is optionally obligately heterotrophic, the cell comprising one or more exogenous nucleic acids that encode an acyl transferase, a thioesterase, a ketoacyl ACP synthase (KAS), a ketoacyl CoA synthase (KCS), or an elongase, wherein the fatty acid profile of the cell is altered by the expression of the one or more exogenous nucleic acids and the lipid is in enriched in stearate-oleate-stearate (SOS) triacylglycerides as compared to non-recombinant cell of the genus Prototheca.
2. The recombinant cell of claim 1 , wherein the acyltransferase is lysophosphatidic acid acyltransferase.
3. The recombinant cell of claim 1 , wherein the acyltransferase is glycerol-3-phosphate acyltransferase.
4. The recombinant cell of claim 1 , wherein the acyltransferase is diacylglycerol acyltransferase.
5. The recombinant cell of claim 1 , wherein the ketoacylsynthase is KASI.
6. The recombinant cell of claim 1 , wherein the ketoacylsynthase is KASII.
7. The recombinant cell of claim 1 , wherein the ketoacylsynthase is KASIII.
8. The recombinant cell of claim 1 , wherein the ketoacylsynthase is KASIV.
9. The recombinant cell of claim 1 , further comprising an exogenous nucleic acid that encodes an active invertase.
10. The recombinant cell of claim 1 , further comprising an allelic disruption of an endogenous thioesterase, ketoacyl ACP synthase, acyltransferase, or desaturase.
11. The recombinant cell of claim 1 , wherein the cell further comprises a nucleic acid that encodes an inhibitory RNA molecule.
12. The recombinant cell of claim 11 , wherein the inhibitory RNA molecule is RNAi, siRNA, miRNA, dsRNA, antisense, or hairpin RNA.
13. The recombinant cell of claim 12 , wherein the inhibitory RNA molecule is a hairpin RNA.
14. A recombinant cell of the genus Prototheca comprising at least 20% lipid by dry cell weight, wherein the cell is optionally obligately heterotrophic, the cell comprising one or more exogenous nucleic acids that encode an acyl transferase, a thioesterase, a ketoacyl ACP synthase (KAS), a ketoacyl CoA synthase (KCS), or an elongase, the cell further comprising a nucleic acid that encodes an active invertase, wherein the fatty acid profile of the cell is altered by the expression of the one or more exogenous nucleic acids and the lipid is in enriched in stearate-oleate-stearate (SOS) triacylglycerides as compared to non-recombinant cell of the genus Prototheca.
15. A method of producing an oil from the cell of claim 1 , the method comprising:
a. providing the cell;
b. cultivating the cell; and
c. obtaining the oil from the cell.
16. The method of claim 15 , wherein the acyltransferase is lysophosphatidic acid acyltransferase, glycerol-3-phosphate acyltransferase, or diacylglycerol acyltransferase.
17. The method of claim 15 , wherein the ketoacyl synthase is KASI, KASII, KASIII or KASIV.
18. The method of claim 15 , further comprising an allelic disruption of an endogenous thioesterase, ketoacyl synthase, acyltransferase, or desaturase.
19. The method of claim 18 , wherein the endogenous desaturase gene that is disrupted is stearoyl-ACP desaturase or fatty acyl desaturase.
20. The method of claim 18 , wherein the ketoacyl synthase gene that is disrupted is KASI.
21. The method of claim 18 , wherein the thioesterase gene that is disrupted is FatA.
22. The method of claim 15 , wherein the SOS triacylglyceride content of the lipid by dry cell weight is at least 40%.
23. The method of claim 15 , wherein the SOS triacylglyceride content of the lipid by dry cell weight is at least 60%.
24. The cell of claim 10 , wherein the endogenous desaturase gene that is disrupted is stearoyl-ACP desaturase or fatty acyl desaturase.
25. The cell of claim 10 , wherein the ketoacyl synthase gene that is disrupted is KASI.
26. The cell of claim 10 , wherein the thioesterase gene that is disrupted is FATA.
27. The cell of claim 10 , wherein the SOS triacylglyceride content of the lipid by dry cell weight is at least 40%.
28. The method of claim 10 , wherein the SOS triacylglyceride content of the lipid by dry cell weight is at least 60%.