Cells and method for producing acetone

1. An acetogenic cell that is able to form acetone and is genetically modified relative to its wild type, so that the acetogenic cell is able to form more acetone compared with its wild type,

wherein the acetogenic cell is able to utilize CO 2 as a terminal electron acceptor to form acetate, and

wherein the acetogenic cell is not Clostridium acetobutylicum or a genetically-modified variant thereof.

2. The acetogenic cell of claim 1 , wherein the acetogenic cell is able to form acetone from at least one carbon source selected from the group consisting of carbon dioxide and carbon monoxide.

3. The acetogenic cell of claim 1 , wherein the acetogenic cell, compared with its wild type, has an increased activity of at least one enzyme selected from the group consisting of:

(1) an enzyme which catalyzes the reaction of acetyl-coenzyme A to acetoacetyl-coenzyme A;

(2) an enzyme which catalyzes the reaction of acetoacetyl-coenzyme A to acetoacetate; and

(3) an enzyme which catalyzes the reaction of acetoacetate to acetone.

4. The acetogenic cell of claim 3 , wherein

(1) is an acetyl-CoA-C-acetyl transferase (EC 2.3.1.9);

(2) is a butyrate-acetoacetate-CoA-transferase (EC 2.8.3.9) or an acyl-CoA-hydrolase (EC 3.1.2.20); and

(3) is an acetoacetate decarboxylase (EC 4.1.1.4).

5. The acetogenic cell of claim 1 , wherein the acetogenic cell is a microorganism selected from the group consisting of Thermoanaerobacter kivui, Acetobacterium woodii, Acetoanaerobium notera, Clostridium aceticum, Butyribacterium methylotrophicum, Moorella thermoacetica, Eubacterium limosum, Peptostreptococcus productus, Clostridium ljungdahlii and Clostridium carboxidivorans.

6. The acetogenic cell of claim 2 , wherein the acetogenic cell, compared with its wild type, has an increased activity of at least one enzyme selected from the group consisting of:

(1) an enzyme which catalyzes the reaction of acetyl-coenzyme A to acetoacetyl-coenzyme A;

(2) an enzyme which catalyzes the reaction of acetoacetyl-coenzyme A to acetoacetate; and

(3) an enzyme which catalyzes the reaction of acetoacetate to acetone.

7. The acetogenic cell of claim 5 , wherein the acetogenic cell, compared with its wild type, has an increased activity of at least one enzyme selected from the group consisting of:

(1) an enzyme which catalyzes the reaction of acetyl-coenzyme A to acetoacetyl-coenzyme A;

(2) an enzyme which catalyzes the reaction of acetoacetyl-coenzyme A to acetoacetate; and

(3) an enzyme which catalyzes the reaction of acetoacetate to acetone.

8. The acetogenic cell of claim 3 , which has an increased activity of (1) and wherein (1) is an acetyl-CoA-acetyl transferase (EC 2.3.1.9).

9. The acetogenic cell of claim 3 , which has an increased activity of (2) and wherein (2) is a butyrate-acetoacetate-CoA-transferase (EC 2.8.3.9).

10. The acetogenic cell of claim 3 , which has an increased activity of (2) and wherein (2) is an acyl-CoA-hydrolase (EC 3.1.2.20).

11. The acetogenic cell of claim 3 , which has an increased activity of (3) and wherein (3) is an acetoacetate decarboxylase (EC 4.1.1.4).

12. The acetogenic cell of claim 3 , which has an increased activity of (1) and (2) and wherein (1) is an acetyl-CoA-acetyl transferase (EC 2.3.1.9) and (2) is a butyrate-acetoacetate-CoA-transferase (EC 2.8.3.9).

13. The acetogenic cell of claim 11 , which has an increased activity of (2) and wherein (2) is a butyrate-acetoacetate-CoA-transferase (EC 2.8.3.9).

14. The acetogenic cell of claim 3 , which has an increased activity of (1) and (2) and wherein (1) is an acetyl-CoA-acetyl transferase (EC 2.3.1.9) and (2) is an acyl-CoA-hydrolase (EC 3.1.2.20).

15. The acetogenic cell of claim 3 , which has an increased activity of (2) and (3) and wherein (2) is an acyl-CoA-hydrolase (EC 3.1.2.20) and (3) is an acetoacetate decarboxylase (EC 4.1.1.4).

16. The acetogenic cell of claim 3 , which is a microorganism selected from the group consisting of Thermoanaerobacter kivui, Acetobacterium woodii, Acetoanaerobium notera, Clostridium aceticum, Butyribacterium methylotrophicum, Moorella thermoacetica, Eubacterium limosum, Peptostreptococcus productus, Clostridium ljungdahlii and Clostridium carboxidivorans.

17. The acetogenic cell of claim 1 , which has an increased activity of (1) an enzyme which catalyzes the reaction of acetyl-coenzyme A to acetoacetyl-coenzyme A.

18. The acetogenic cell of claim 1 , which has an increased activity of (2) an enzyme which catalyzes the reaction of acetoacetyl-coenzyme A to acetoacetate.

19. The acetogenic cell of claim 1 , which has an increased activity of (3) an enzyme which catalyzes the reaction of acetoacetate to acetone.

20. A method for producing acetone, the method comprising:

A) contacting a cell of claim 1 with a nutrient medium comprising at least one carbon source selected from the group consisting of carbon dioxide and carbon monoxide; and

B) cultivating the cell under at least one condition that enables the cell to form acetone.

21. The method of claim 20 , further comprising isolating the acetone.