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. An oleaginous microalgal cell of genus Prototheca , the cell comprising an active exogenous KASII (ketoacyl ACP synthase) gene encoding a protein having at least 95% sequence identity to the protein encoded by nucleotides 4039 to 5328 of SEQ ID NO:95 and producing an oil comprising triglycerides, wherein the oil is enriched in stearic-oleic-stearic.
2. The cell of claim 1 , further comprising an exogenous gene that encodes an active fatty acyl-ACP thioesterase.
3. The cell of claim 1 , wherein the cell further comprises nucleic acids operable to reduce the expression of a stearoyl-ACP desaturase.
4. The cell of claim 3 , wherein the oil is enriched in triglycerides of the saturated-unsaturated-saturated type, wherein the sum of palmitic-oleic-palmitic, stearic-oleic-stearic and palmitic-oleic-stearic is at least 30% of the triglycerides.
5. The cell of claim 4 , wherein the sum of palmitic-oleic-palmitic, stearic-oleic-stearic and palmitic-oleic-stearic is at least 50% of the triglycerides.
6. The cell of claim 5 , wherein the oil comprises triglycerides comprising at least 50% stearic-oleic-stearic, and optionally less than 10% stearic-stearic-stearic.
7. The cell of claim 1 , further comprising a knockout or knockdown of a stearoyl-ACP desaturase gene, a FatA gene, or both.
8. The cell of claim 4 , wherein the oil comprises POP at 16%±20%, POS at 38%±20%, and SOS at 23%±20%.
9. The cell of claim 7 , wherein the cell further comprises nucleic acids operable to reduce the expression of a delta 12 fatty acid desaturase, optionally via a regulatable promoter, so as to produce an oil with linoleic and linolenic acids totaling 5 area percent or less.
10. The cell of claim 4 , wherein the oil has greater than 65% stearic-oleic-stearic, less than 45% unsaturated fatty acid, less than 5% polyunsaturated fatty acids, less than 1% lauric acid, and less than 2% trans fatty acids.
11. A method for producing an oil comprising providing or cultivating a cell according to claim 1 , and extracting the oil.
12. The cell of claim 1 , wherein the cell is an obligately heterotrophic cell.
13. The cell of claim 1 , comprising an exogenous sucrose invertase gene so that the cell can grow on sucrose as a sole carbon source.
14. The cell of claim 3 , wherein the nucleic acids operable to reduce the expression of a stearoyl-ACP desaturase disrupt one or both alleles of the endogenous stearoyl-ACP desaturase coding sequences.
15. The cell of claim 3 , wherein the nucleic acids operable to reduce the expression of a stearoyl-ACP desaturase is a nucleic acid that encodes an RNA construct that reduces the activity of stearoyl-ACP desaturase.
16. An oleaginous microalgal cell of genus Prototheca , the cell comprising an exogenous gene encoding an active KAS II (ketoacyl ACP synthase) enzyme that has at least 95% sequence identity to the protein encoded by nucleotides 4039 to 5328 of SEQ ID NO:95 and nucleic acids operable to reduce the expression of a stearoyl-ACP desaturase, the cell producing an oil comprising triglycerides, wherein the oil is enriched in triglycerides of the saturated-unsaturated-saturated type.
17. The cell of claim 16 , wherein the palmitic-oleic-palmitic, stearic-oleic-stearic and palmitic-oleic-stearic in the oil comprise at least 30% in sum.
18. The cell of claim 16 , wherein the palmitic-oleic-palmitic, stearic-oleic-stearic and palmitic-oleic-stearic in the oil comprise at least 50% in sum.
19. The cell of claim 16 , wherein the stearic-oleic-stearic in the oil comprise at least 40%.
20. The cell of claim 16 , wherein the stearic-oleic-stearic in the oil comprise at least 50%.