Sequestration of carbon dioxide with hydrogen to useful products
Provided herein are genetically engineered microbes that include at least a portion of a carbon fixation pathway, and in one embodiment, use molecular hydrogen to drive carbon dioxide fixation. In one embodiment, the genetically engineered microbe is modified to convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof at levels greater than a control microbe. Other products may also be produced. Also provided herein are cell free compositions that convert acetyl CoA, molecular hydrogen, and carbon dioxide to 3-hydroxypropionate, 4-hydroxybutyrate, acetyl CoA, or the combination thereof. Also provided herein are methods of using the genetically engineered microbes and the cell free compositions.
1. A genetically engineered microbe modified to convert acetyl CoA, molecular hydrogen and carbon dioxide to 4-hydroxybutyrate, wherein the 4-hydroxybutyrate is produced at increased levels compared to a control microbe, wherein the microbe is a hyperthermophile, wherein the microbe is a member of the domain Archaea or a member of the domain Bacteria, and wherein the microbe comprises an exogenous polynucleotide encoding a polypeptide, wherein the polypeptide has an activity selected from 3-hydroxypropionate:CoA ligase activity, 3-hydroxypropionyl-CoA dehydratase activity, acryloyl-CoA reductase activity, methylmalonyl-CoA epimerase activity, methylmalonyl-CoA mutase activity, and succinate semialdehyde reductase activity.
2. The genetically engineered microbe of claim 1 wherein the archeon is a member of the Order Thermococcales, a member of the Order Sulfolobales, or a member of the Order Thermotogales.
3. The genetically engineered microbe of claim 2 wherein the archeon is Thermococcus kodakarensis, T. onnurineus, Sulfolobus solfataricus, S. islandicus, S. acidocaldarius , or Pyrococcus furiosus.
4. The genetically engineered microbe of claim 1 wherein the microbe comprises an exogenous polynucleotide encoding a polypeptide, wherein the polypeptide has an activity selected from acetyl/propionyl-CoA carboxylase activity, malonyl/succinyl-CoA reductase activity, and malonate semialdehyde reductase activity.
5. The genetically engineered microbe of claim 1 wherein the microbe produces 4-hydroxybutyrate, and wherein the microbe comprises an exogenous polynucleotide encoding a polypeptide, wherein the polypeptide has an activity selected from 4-hydroxybutyrate:CoA ligase activity, 4-hydroxybutyrl-CoA dehydratase activity, crotonyl-CoA hydratase/(S)-3-hydroxybutyrl-CoA dehydrogenase activity, and acetoacetyl-CoA β-ketothiolase activity.
6. The genetically engineered microbe of claim 1 wherein an exogenous polynucleotide is operably linked to a temperature sensitive promoter, to a constitutive promoter, or to a non-regulated promoter.
7. The genetically engineered microbe of claim 1 wherein the microbe further comprises a hydrogenase.
8. The genetically engineered microbe of claim 7 wherein the hydrogenase is a NADPH-dependent hydrogenase.
9. The genetically engineered microbe of claim 8 wherein the microbe comprises exogenous polynucleotide encoding subunits of the NADPH-dependent hydrogenase.
10. The genetically engineered microbe of claim 9 wherein the subunits of the NADPH-dependent hydrogenase comprise a hydrogenase alpha subunit and a hydrogenase delta subunit.
11. The genetically engineered microbe of claim 10 wherein the subunits of the NADPH-dependent hydrogenase further comprise a hydrogenase beta subunit and a hydrogenase gamma subunit.
12. The genetically engineered microbe of claim 1 wherein the hyperthermophile is a Caldicellulosiruptor spp.
13. The genetically engineered microbe of claim 12 wherein the Caldicellulosiruptor is C. bescii.
14. A method comprising incubating the genetically engineered microbe of claim 1 under anaerobic conditions suitable for converting acetyl CoA, molecular hydrogen, and carbon dioxide to 4-hydroxybutyrate.
15. The method of claim 14 further comprising recovering the 4-hydroxybutyrate.
16. The method of claim 14 wherein the incubating comprises an incubation temperature of at least 75° C.