Fermentation process for producing isopropanol using a recombinant microorganism
View Patent ↗The invention provides, inter alia, methods for the production of acetone, isopropanol and/or precursors of acetone and/or isopropanol by microbial fermentation of substrates comprising CO, genetically modified microorganisms of use in such methods, nucleic acids suitable for preparation of genetically modified microorganisms, a novel alcohol dehydrogenase and nucleic acids encoding same.
1. A method for producing a product comprising culturing a recombinant microorganism comprising an exogenous thiolase, an exogenous CoA transferase, and an exogenous decarboxylase in the presence of a gaseous substrate sornprisina one or more of CO, CO2, and H2 to produce isopropanol, wherein
the recombinant microorganism is derived from a parental microorganism selected from the group consisting of Clostridium autoethanogenurn Clostridium lfungdahlii , and Clostridium ragsdalei,
the exogenous thiolase is acetyl-CoA acetyltransferase (EC 2.3.1.9),
the exogenous CoA transferase is acetoacetyl-Cokacetate CoA transferase (EC 2.8.3.9), and
the exogenous decarboxylase is acetoacetate decarboxylase (EC 4.1.1.4) or alpha-ketolsovalerate decarboxylase (EC 4.1.1.74).
2. The method of claim 1 , wherein the thiolase is Clostridium acetobutylicum ThlA comprising SEQ ID NO: 42.
3. The method of claim 1 , wherein the acetoacetyl-CoA:acetate CoA transferase is Clostridium beijerinckii CtfA comprising SEQ ID NO: 43 and Clostridium beijerinckii CtfB comprising SEQ ID NO: 44.
4. The method of claim 1 , wherein the acetoacetate decarboxylase is Clostridium beijerinckii Adc comprising SEQ ID NO: 45.
5. The method of claim 1 , wherein the alpha-ketoisovalerate decarboxylase is Lactococcus lactis KivD comprising SEQ ID NO: 73.
6. The method of claim 1 , wherein the recombinant microorganism further comprises an endogenous or exogenous alcohol dehydrogenase.
7. The method of claim 6 , wherein the endogenous or exogenous alcohol dehydrogenase is alcohol dehydrogenase (Adh) (EC 1.1.1.2) or alcohol dehydrogenase (Adh2)(EC 1.1.1.1).
8. The method of claim 1 , wherein the recombinant microorganism is a carboxydotrophic and acetogenic bacterium.
9. The method of claim 1 , wherein the parental microorganism does not produce acetone or isopropanol.
10. The method of claim 1 , wherein the parental microorganism is Clostridium autoethanogenum or Clostridium ljungdahlii.
11. The method of claim 10 , wherein the parental microorganism is Clostridium autoethanogenum DSM23693 or Clostridium ljungdahlii DSM13528.
12. The method of claim 1 , wherein the product is isopropanol.
13. The method of claim 1 , wherein the gaseous substrate comprises 20-70% CO.
14. The method of claim 1 , wherein the gaseous substrate is derived from an industrial process selected from the group consisting of ferrous metal products manufacturing, non-ferrous products manufacturing, petroleum refining, coal gasification, biomass gasification, electric power production, carbon black production, and coke manufacturing.