Process for production of alcohols by microbial fermentation
The invention provides method for producing butanediol and specifically 2,3-butanediol by anaerobic fermentation of a gaseous substrate comprising CO by a culture of at least one micro-organism. In accordance with particular methods of the invention, 2,3-butanediol is produced by anaerobic fermentation of substrates including carbohydrates and carbon monoxide. The invention further provides for the up-regulation of a native 2,3-butanediol dehydrogenase gene in the at least one micro-organism. The 2,3-butanediol can be further converted to compounds such as butene(s), butadiene and methyl ethyl ketone. These compounds can be further converted to chemical products such as 2-butanol.
1. A method of producing 2,3-butanediol by microbial fermentation of a gaseous substrate comprising CO, the method comprising:
a. continuously providing the gaseous substrate to a bioreactor; and
b. anaerobically fermenting the substrate in the bioreactor, the bioreactor comprising a culture of at least one acetogenic bacterium to produce 2,3-butanediol; wherein the gaseous substrate is provided such that a specific rate of CO uptake of at least 0.4 mmol CO/gram dry cells weight of bacteria/minute by the culture is maintained and 2,3-butanediol is produced at a productivity greater than 0.2 g/L/per day.
2. The method of claim 1 further comprising converting the 2,3-butanediol to a compound selected from the group consisting of butene(s), butadiene, methyl ethyl ketone (MEK) and mixtures thereof.
3. The method of claim 2 further comprising converting the butene(s), butadiene or methyl ethyl ketone to a chemical product.
4. The method of claim 3 where the methyl ethyl ketone is converted to 2-butanol.
5. The method according to claim 1 , wherein the substrate is provided such that a specific uptake rate of at least 0.6 mmol CO/g/min is maintained.
6. The method according to claim 1 , wherein the substrate is provided such that a specific uptake rate of at least 0.8 mmol CO/g/min is maintained.
7. The method according to claim 1 , wherein the substrate is provided such that a specific uptake rate of at least 1.0 mmol CO/g/min is maintained.
8. The method according to claim 1 , wherein the gaseous substrate comprises at least 15% to about 100% CO by volume.
9. The method according to claim 1 , wherein the gaseous substrate comprises a gas obtained as a by-product from an industrial process.
10. The method according to claim 9 , wherein the gaseous substrate comprises waste gas from a steel mill.
11. The method according to claim 1 wherein the acetogenic bacterium is Clostridium autoethanogenum.
12. The method according to claim 1 wherein ethanol is produced as a co-product of the fermentation.
13. The method according to claim 1 wherein the acetogenic bacterium is the Clostridium autoethanogenum strain deposited at the German Collection of Microorganisms and Cell Cultures (DSMZ) under the accession number DSM 19630.
14. A method of producing 2,3-butanediol by microbial fermentation of a gaseous substrate comprising CO, the method-comprising:
a. continuously providing the gaseous substrate to a bioreactor;
b. anaerobically fermenting the gaseous substrate in the bioreactor, the bioreactor comprising a culture of at least one acetogenic bacterium, wherein the at least one acetogenic bacterium comprises at least one 2,3-butanediol dehydrogenase gene;
c. upregulating the 2,3-butanediol dehydrogenase gene by providing the gaseous substrate such that the specific uptake of CO by the at least one acetogenic bacterium is at least 0.4 mmol/g/min, and such that 2,3-butanediol is produced at a productivity greater than 0.2 g/L/per day; and
d. converting the 2,3-butanediol produced in step (c) to a compound selected from the group consisting of butane, butadiene, methyl ethyl ketone and mixtures thereof.
15. The method according to claim 14 wherein the acetogenic bacterium comprises Clostridium autoethanogenum.
16. The method according to claim 15 wherein the acetogenic bacterium is the Clostridium autoethanogenum strain deposited at the German Collection of Microorganisms and Cell Cultures (DSMZ) under the accession number DSM 19630.
17. The method of claim 14 further comprising converting the butene(s), butadiene or methyl ethyl ketone to a chemical product.
18. The method according to claim 14 , wherein the substrate is provided such that a specific uptake rate of at least 0.6 mmol CO/g/min is maintained.
19. The method according to claim 14 , wherein the gaseous substrate comprises at least 15% to about 100% CO by volume.
20. The method according to claim 14 , wherein the gaseous substrate comprises waste gas from a steel mill.
21. The method according to claim 14 wherein ethanol is produced as a co-product of the fermentation.