Production of isoprenoids
Provided herein are methods for a robust production of isoprenoids via one or more biosynthetic pathways. Also provided herein are nucleic acids, enzymes, expression vectors, and genetically modified host cells for carrying out the subject methods. Also provided herein are fermentation methods for high productivity of isoprenoids from genetically modified host cells.
1. A method for producing a heterologous C 5 -C 20 isoprenoid compound in a yeast host cell, the method comprising:
(a) obtaining a plurality of yeast host cells that are capable of making the heterologous C 5 -C 20 isoprenoid compound, each said yeast host cell comprising one or more heterologous nucleic acids capable of expressing each enzyme of the MEV pathway or each enzyme of the DX P pathway;
(b) culturing the yeast host cells in a medium with a glucose feed or a mixed feed comprising glucose and ethanol, wherein the culturing includes a period of time where the host cells are phosphate-limited to yield a fermentation reaction mixture comprising medium, cells, and the heterologous C 5 -C 20 isoprenoid compound; and
(c) recovering the heterologous C 5 -C 20 isoprenoid compound from the medium,
wherein the yeast host cells produce up to 27.36 grams of the heterologous C 5 -C 20 isoprenoid compound per liter of fermentation reaction mixture, and
wherein the heterologous C 5 -C 20 isoprenoid compound is amorphadiene.
2. The method of claim 1 , wherein the yeast host cells produce between 1.92 and 27.36 grams/liter of amorphadiene.
3. The method of claim 1 , wherein the yeast host cells produce between 5.52 and 27.36 grams/liter of amorphadiene.
4. The method of claim 1 , wherein the yeast host cells produce between 9.68 and 27.36 grams/liter of amorphadiene.
5. The method of claim 1 , wherein the yeast host cells are S. cerevisiae.
6. The method of claim 1 , wherein each said yeast host cell comprises one or more heterologous nucleic acids capable of expressing an acetyl-CoA acetyltransferase, an HMG-CoA synthase, an HMG-CoA reductase, a mevalonate kinase, a phosphomevalonate kinase and a mevalonate pyrophosphate decarboxylase.
7. The method of claim 1 , wherein the medium comprises a batch medium and a feed medium.
8. The method of claim 7 , wherein the hatch medium is supplied with 4 to 8 grams/liter phosphate.
9. The method of claim 1 , wherein the yeast host cells are maintained under phosphate limited conditions for at least four hours.
10. The method of claim 7 , wherein the phosphate in the batch medium is consumed in about 40 hours.
11. The method of claim 7 , wherein the feed medium is supplied with no phosphate or 0.5 grams/liter phosphate.
12. The method of claim 7 , wherein the feed medium is supplied at a feed rate of 8.6 grams/hour/liter.
13. The method of claim 7 , wherein the batch medium comprises glucose at 19.5 grams/liter and the feed medium comprises glucose at 425 gams/liter or 578 grams/liter.
14. The method of claim 13 , wherein the feed medium comprises glucose at 425 grams/liter and 237 milliliters/liter 95% ethanol.
15. The method of claim 1 , wherein the phosphate is supplied to the medium as potassium dihydrogen phosphate (KH 2 PO 4 ).