MICROBIAL CONVERSION OF METHANE

• US 20150111265A1
• Filed: 10/20/2014
• Published: 04/23/2015
• Est. Priority Date: 10/18/2013
• Status: Active Grant

• Current Assignee: Alliance For Sustainable Energy LLC, Lanzatech NZ Incorporated (LanzaTech Global, Inc.), University of Washington
• Original Assignee: Alliance For Sustainable Energy LLC, LanzaTech New Zealand Ltd. (LanzaTech Global, Inc.), University of Washington
• Inventors: Lidstrom, Mary Elizabeth, Kalyuzhnaya, Marina Georgievna, Griffin, Derek Wayne, Bourdakos, Nicholas, Pienkos, Philip Thomas, Laurens, Lieve Maria Louisa
• Granted Patent: US 11,220,700 B2
• Time in Patent Office: Days
• US Class Current: 435/134
• CPC Class Codes: C12P 21/00 Preparation of peptides or proteins single cell protein C12N1/00
• CPC Class Codes: C12P 5/023 Methane
• CPC Class Codes: C12P 7/6463 obtained from glyceride producing microorganisms, e.g. single cell oil
• CPC Class Codes: C12P 7/649 Biodiesel, i.e. fatty acid alkyl esters
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel
• CPC Class Codes: Y02E 50/30 Fuel from waste, e.g. synthetic alcohol or diesel

Abstract

This invention relates to a process for producing lipids and amino acids from a gaseous substrate comprising methane and oxygen. The process uses a culture of a methanotrophic microorganism in a liquid nutrient medium. The methanotrophic microorganism can be a Methylomicrobium bacterium and more specifically Methylomicrobium buryatense 5GB1. The lipid products can be in the cellular membrane of the methanotroph and can be extracted in a separate extraction zone.

Claims

1. A process for production of at least one product by microbial conversion of a gaseous substrate, comprising:

(a) Providing a gaseous substrate comprising CH₄ and O₂ to a bioreactor comprising a culture of at least one methanotrophic microorganism in a liquid nutrient medium; and

(b) microbially converting under fermentation conditions the gaseous substrate to at least one product in the cell biomass selected from the group consisting of lipids, proteins, amino acids and mixtures thereof and excreted fatty acids.

2. The process of claim 1, wherein the lipids are selected from the group consisting of fatty acids, glycolipids, sphingolipids, saccharolipids, polyketides, sterol lipids, hopanoids, phospholipids and prenol lipids, or mixtures thereof.

3. The process of claim 2, wherein the lipids are further converted into compounds selected from the group consisting of renewable diesel, biodiesel, diesel, diesel components fatty acid methyl esters and fatty acid ethyl esters.

4. The process of claim 1, wherein the gaseous substrate comprises O₂ and CH₄ at a ratio ranging from about 5:

1 to about 0.9;

1 O₂;

CH₄.

5. The process of claim 4, wherein the gaseous substrate comprises O₂ and CH₄ at a ratio from about 1.3:

1 to about 0.9;

1 O₂;

CH₄.

6. The process of claim 1 where the microorganism uptakes CH₄ and O₂ at a ratio from about 1:

1 to about 2.5;

1 O₂ to CH₄.

7. The process of claim 1 where the microorganism grows at a rate of at least about 0.08 hr⁻

1.

8. The process of claim 1 where the nutrient medium comprises Cu⁺⁺ and the microorganism uptakes the Cu⁺⁺ at a rate from about 7 to about 20 μ

M/gDCW.

9. The process of claim 1 where the nutrient medium comprises NO₃⁻

and the microorganism uptakes the NO₃⁻

at a rate from about 5 to about 8 mmol/gDCW.

10. The process of claim 1 where the nutrient medium comprises PO₄⁻

3 and the microorganism uptakes the PO₄<sup>−

3</sup> at a rate from about 1.4 to about 2 mmol/gDCW

11. The process of claim 1, wherein the culture of at least one methanotrophic microorganism is selected from the group consisting of the genera Methylococcus, Methylomonas, Methylomicrobium, Methylobacter, Methylocaldum, Methylosphaera, Methylocystis and Methylosinus, or mixtures thereof.

12. The process of claim 1, wherein the culture comprises Methylomicrobium buryatense.

13. The process of claim 1 wherein at least a portion of the gaseous substrate exits the bioreactor unreacted through a gas outlet and is recycled back to the bioreactor for further conversion.

14. The process of claim 1 further comprising maintaining the pH of the liquid nutrient media in the range from about 6 to about 11.

15. The process of claim 1 further comprising maintaining the temperature of the liquid nutrient media in the range from about 5 to about 50°

C.

16. A process for production of at least one product by microbial conversion of a gaseous substrate, comprising:

(a) providing a substrate comprising oxygen and at least one component selected from CH₄, CH₃OH and mixtures thereof to a bioreactor comprising a liquid nutrient media and a culture of at least one methanotrophic microorganism;

(b) microbially converting the substrate to produce at least one product selected from lipids and amino acids in the cellular biomass of the microorganism; and

(c) extracting the at least one product from the cellular membrane of the microorganism.

17. The process of claim 16, wherein the lipids are selected from the group consisting of fatty acids, glycolipids, sphingolipids, saccharolipids, polyketides, sterol lipids, hopanoids, phospholipids and prenol lipids, and mixtures thereof.

18. The process of claim 16 wherein the gaseous substrate comprises O₂ and CH₄ at a ratio ranging 5:

1-0.5;

1 O₂;

CH₄.

19. The process of claim 16 where the microorganism uptakes CH₄ and O₂ at a ratio from about 1:

1 to about 2.5;

1 O₂ to CH₄.

20. The process of claim 16 further comprising blending the CH₄ with the CH₃OH prior to being provided to the bioreactor.

21. The process of claim 16, wherein the culture of at least one methanotrophic microorganism is selected from the genus consisting of Methylococcus, Methylomonas, Methylomicrobium, Methylobacter, Methylocaldum/Methylothermus, Methylomarinum, Methylomarinovum, Methylocystis and Methylosinus, or mixtures thereof.

22. The process of claim 21, wherein the culture comprises Methylomicrobium buryatense.

23. The process of claim 16, wherein the extracting step comprises a cell disruption step and a solvent extraction step.

24. The process of claim 23, wherein the solvent extraction step produces a light phase comprising at least one product and a heavy phase comprising spent biomass.

25. The process of claim 24 wherein at least of portion of the spent biomass is used to prepare single cell protein.

26. The process of claim 24, further comprising passing at least a portion of the heavy phase to an anaerobic digester where at least a portion of the heavy phase is converted to biogas.

27. The process of claim 26, wherein at least a portion of the produced biogas is provided to the bioreactor.

28. The process of claim 16, further comprising converting at least at a portion of the extracted product to at least one compound selected from the group consisting of renewable diesel, biodiesel, diesel, diesel derivatives, fatty acid methyl esters and fatty acid ethyl esters.