Methane oxidation methods and compositions

Patent metadata

Field	Value
Publication number	US-10011813-B2
Application number	US-201615294704-A
Country	US
Kind code	B2
Filing date	Oct 15, 2016
Priority date	Oct 16, 2015
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

The disclosure provides devices and methods to produce electrical energy from microorganisms capable of metabolizing methane.

First claim

What is claimed is:

1. A bioelectrochemical device comprising:
a methane source to provide methane to the bioelectrochemical device;
an aqueous solvent system that comprises an aqueous redox-active soluble electron acceptor that is re-circulated in the bioelectrochemical device, wherein the aqueous redox-active soluble electron acceptor is selected from the group consisting of 2,6-AQDS (9,10-anthraquinone-2,6-disulfonate), 2,7-AQDS (9,10-anthraquinone-2,7-disulfonate), 1,5-AQDS (9,10-anthraquinone-1,5-disulfonate), Fe(III)-citrate, Fe(III)-EDTA, humic acids, and melanin;
a bioreactor comprising one or more different types of C 1 -metabolizing microorganisms that are capable of metabolizing methane and reducing the aqueous redox-active soluble electron acceptor to a reduced electron acceptor;
a fuel cell comprising:
an anode that can oxidize the reduced electron acceptor back to the electron acceptor,
a cathode that can reduce an oxidant, and
an ion conductor placed between the cathode and anode, wherein the ion conductor selectively transports positively or negatively charged ions.

2. The bioelectrochemical device of claim 1 , wherein the bioelectrochemical device further comprises one or more of the following:
a series of tubes that are fluidly in contact with the bioreactor and the fuel cell;
a pump that powers the recirculation of the solvent system;
a check valve that selectively allows the passage of methane into the bioelectrochemical device;
a set of valves and inlets that are fluidly in contact with the aqueous solvent system that allow for addition or adjustment of the aqueous solvent system; and/or
a CO 2 extraction device that removes dissolved CO 2 from the aqueous solvent system.

3. The bioelectrochemical device of claim 2 , wherein the bioelectrochemical device comprises:
the pump that powers the recirculation of the solvent system;
the check valve that selectively allows the passage of methane into the bioelectrochemical device;
the set of valves and inlets that are fluidly in contact with the aqueous solvent system that allow for addition or adjustment of the aqueous solvent system;
the CO 2 extraction device that removes dissolved CO 2 from the aqueous solvent system; and/or
the series of tubes that are fluidly in contact with the bioreactor, and the fuel cell, wherein the series of tubes are also fluidly in contact with the pump, the check valve, the set of valves and inlets/outlets, and the CO 2 extraction device.

4. The bioelectrochemical device of claim 1 , wherein the one or more different types of C 1 -metabolizing microorganisms are methanogens, methanotrophs, and/or a recombinantly engineered organism(s) that are capable of oxidizing methane.

5. The bioelectrochemical device of claim 1 , wherein the one or more different types of C 1 -metabolizing microorganisms are anaerobic methanotrophs; and wherein the aqueous solvent is substantially free or devoid of dissolved oxygen.

6. The bioelectrochemical device of claim 1 , wherein the methane source is a methane producing fermentation system utilizing biomass, coal, human waste, and/or animal waste as a fuel source, and/or a purified fuel gas stream that is enriched with methane.

7. The bioelectrochemical device of claim 1 , wherein the aqueous redox-active soluble electron acceptor is a single-electron acceptor with a standard reduction potential more positive than ca. -240 mV.

8. The bioelectrochemical device of claim 1 , wherein the aqueous solvent system further comprises one or more of the following: buffers, salts, and/or nutrients.

9. The bioelectrochemical device of claim 1 , wherein the bioreactor comprises:
a housing with two surfaces an inner surface that comes into contact with the aqueous solvent and an outer surface that does not come into contact with the aqueous solvent;
at least two ports to allow for the aqueous solvent to enter the bioreactor and to allow for the aqueous solvent to exit the bioreactor.

10. The bioelectrochemical device of claim 9 , wherein the bioreactor comprises one or more C 1 -metabolizing microorganisms that are grown or contained within a bed of media or solid support(s).

11. The bioelectrochemical device of claim 10 , wherein the media and solid support comprises a high surface area so that C 1 -metabolizing microorganisms can spread across the surface of the media or the solid support.

12. The bioelectrochemical device of claim 11 , wherein the solid support is comprised of a porous or very porous material.

13. The bioelectrochemical device of claim 9 , wherein the bioreactor further comprises filters or membranes that prevent the passage of C 1 -metabolizing microorganisms or cellular debris out of the bioreactor.

14. The bioelectrochemical device of claim 1 , wherein the aqueous solvent flows into the top of the fuel cell and exits out the bottom of the fuel cell.

15. The bioelectrochemical device of claim 1 , wherein the aqueous solvent flows into the bottom of the bioreactor and exits out the top of the bioreactor.

16. The bioelectrochemical device of claim 1 , wherein the anode and cathode of the fuel cell comprise of electrodes made of carbon or metals such as titanium, and modified by coating with platinum or platinum ruthenium alloys as catalysts; and wherein the ion conductor includes but not limited to a sulfonated tetrafluoroethylene based fluoropolymer-copolymer membrane.

17. The bioelectrochemical device of claim 2 , wherein the CO 2 extraction device is a membrane degasifier device or CO 2 -precipitating chemical reactor.

18. The bioelectrochemical device of claim 3 , wherein the pump, check valve and CO 2 extraction device are electronically controlled directly and/or controlled remotely over a network or wireless communication using a computer, cell phone, and/or tablet.

19. A method to produce direct electrical current comprising providing methane to the bioelectrochemical device of claim 1 .

Assignees

• California Inst Of Techn

Inventors

• Scheller Silvan
• Orphan Victoria J
• Yu Hang

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/06

  Combination of fuel cells with means for production of reactants or for treatment of residues (regenerative fuel cells H01M8/18) · CPC title

• C12M25/02

  Membranes; Filters (filters or filtration in general B01D24/00-B01D41/00) · CPC title

• C12M29/20

  Degassing; Venting; Bubble traps (means for collection or storage of gas C12M23/36; gas collection apparatus for laboratory use B01L5/02) · CPC title

• C12M43/08 Primary

  Bioreactors or fermenters combined with devices or plants for production of electricity · CPC title