Recombinant microalgae cells producing novel oils
Disclosed herein are obligate heterotrophic microalgae cells containing an exogenous gene. In some embodiments the gene is a sucrose utilization gene, and further disclosed are methods of manufacturing triglyceride oils using sugar cane or sugar beets as a feedstock in a heterotrophic fermentation. In other embodiments the feedstock is depolymerized cellulosic material. Also disclosed are cells that produce medium chain fatty acids at levels not produced in non-recombinant cells of the same species and genus.
1. A method for preparing recombinant microalgal cells of the genus Prototheca , the method comprising:
heterotrophically cultivating recombinant microalgal cells of the genus Prototheca in a fermentation broth, the cells comprising a chromosomal knockout of a stearoyl ACP (acyl carrier protein) desaturase allele so that the cells produce an oil having an altered fatty acid profile comprising a reduction in unsaturated fatty acids; and
isolating the cells from the broth.
2. The method of claim 1 , wherein the cells comprise a recombination event in the stearoyl-ACP desaturase allele.
3. The method of claim 2 , wherein the recombination event is a double reciprocal recombination event.
4. The method of claim 2 , wherein a selectable marker gene is incorporated into the chromosome so as to knock out the stearoyl-ACP desaturase allele.
5. The method of claim 1 , wherein the cells are cultivated on glucose, fructose or depolymerized cellulosic material as a carbon source.
6. The method of claim 1 , wherein the microalgal cells are of the species Prototheca moriformis.
7. The method of claim 1 , further comprising isolating the oil from the microalgal cells.