Production of propanols, alcohols, and polyols in consolidated bioprocessing organisms
The present invention provides for novel metabolic pathways leading to propanol, alcohol or polyol formation in a consolidated bioprocessing system (CBP), where lignocellulosic biomass is efficiently converted to such products. More specifically, the invention provides for a recombinant microorganism, where the microorganism expresses one or more native and/or heterologous enzymes; where the one or more enzymes function in one or more engineered metabolic pathways to achieve: (1) conversion of a carbohydrate source to 1,2-propanediol, isopropropanol, ethanol and/or glycerol; (2) conversion of a carbohydrate source to n-propanol and isopropanol; (3) conversion of a carbohydrate source to isopropanol and methanol; or (4) conversion of a carbohydrate source to propanediol and acetone; wherein the one or more native and/or heterologous enzymes is activated, upregulated or downregulated.
1. A recombinant microorganism;
comprising a plurality of heterologous enzymes, wherein said plurality of heterologous enzymes are expressed;
wherein said plurality of heterologous enzymes function in one or more engineered metabolic pathways to convert a carbohydrate source to n-propanol, isopropanol and, optionally, ethanol; and
wherein said plurality of heterologous enzymes is activated or upregulated, and comprises:
a heterologous pyruvate formate lyase,
a heterologous methylglyoxal synthase, and
a heterologous vitamin B12-independent diol dehydratase;
wherein said recombinant microorganism is a yeast.
2. The recombinant microorganism of claim 1 , wherein said carbohydrate source is lignocellulose.
3. The recombinant microorganism of claim 1 , wherein said carbohydrate source is converted to dihydroxyacetone phosphate and glyceraldehyde phosphate.
4. The recombinant microorganism of claim 1 , wherein one of said engineered metabolic pathways comprises conversion of pyruvate to isopropanol.
5. The recombinant microorganism of claim 1 , wherein one of said engineered metabolic pathway comprises conversion of pyruvate to ethanol.
6. The recombinant microorganism of claim 1 , wherein the engineered metabolic pathway that produces isopropanol comprises: (a) conversion of acetyl-CoA to acetate;
(b) conversion of acetyl-CoA to acetoacetyl-CoA; (c) conversion of acetoacetyl-CoA to acetoacetate; (d) conversion of acetoacetate to acetone; and (e) reduction of acetone to isopropanol.
7. The recombinant microorganism of claim 1 , wherein the engineered metabolic pathway that produces ethanol comprises: (a) conversion of acetyl-CoA to ethanol.
8. The recombinant microorganism of claim 1 , wherein said recombinant microorganism is selected from the group consisting of Saccharomyces cerevisiae, Kluyveromyces lactis, Kluyveromyces marxianus, Pichia pastoris, Yarrowia lipolytica , Hansemila polymorphs, Phaffia rhodozyma, Candida ittliis, Arxula adeninivorans, Pichia stipitis, Debaryomyces hansenii, Debaryomyces polymorphic, Schizosaccharomyces pombe, Candida albicans , and Schwanniomyces occidentalis.
9. The recombinant microorganism of claim 3 , wherein one of said engineered metabolic pathways comprises the conversion of dihydroxyacetone phosphate to n-propanol.
10. The recombinant microorganism of claim 9 , wherein said dihydroxyacetone phosphate is converted to methylglyoxal with the heterologous methylglyoxal synthase.
11. The recombinant microorganism of claim 10 , wherein said methylglyoxal is converted to acetol by an aldo-keto reductase or converted to lactaldehyde by a glyoxylate reductase, the heterologous methylglyoxal dehydrogenase or an aldehyde dehydrogenase.
12. The recombinant microorganism of claim 11 , wherein said acetol is converted to propanediol by an aldo-keto reductase or said lactaldehyde is converted to propanediol by an aldehyde reductase.
13. The recombinant microorganism of claim 12 , wherein said propanediol is converted to propanal with the heterologous vitamin B12-independent diol dehydratase.
14. The recombinant microorganism of claim 13 , wherein said propanal is reduced to n-propanol by a dehydrogenase (E.C.1.1.1.202).
15. The recombinant microorganism of claim 6 , wherein acetyl-CoA is converted to acetoacetyl-CoA by a thiolase (E.C.2.3.1.9).
16. The recombinant microorganism of claim 15 , wherein said acetoacetyl-CoA is converted to acetoacetate by a CoA transferase.
17. The recombinant microorganism of claim 16 , wherein said acetoacetate is converted to acetone by an acetoacetate decarboxylase.
18. The recombinant microorganism of claim 17 , wherein said acetone is reduced to isopropanol by an isopropanol dehydrogenase or an alcohol dehydrogenase.
19. The recombinant microorganism of claim 1 , wherein the vitamin B12-independent diol dehydratase is from Clostridium sp., Roseburia sp. or Klebsiella sp.
20. The recombinant microorganism of claim 13 , wherein the vitamin B12-independent diol dehydratase is from Clostridium butyricum, Clostridium glycolicum or Roseburia inulivorans.