MULTI-STAGE BIOREACTOR PROCESSES

• US 20160115505A1
• Filed: 10/22/2015
• Published: 04/28/2016
• Est. Priority Date: 10/22/2014
• Status: Active Grant

• Current Assignee: Lanzatech NZ Incorporated (LanzaTech Global, Inc.)
• Original Assignee: LanzaTech New Zealand Ltd. (LanzaTech Global, Inc.)
• Inventors: Koepke, Michael, Trevethick, Simon Richard, Bromley, Jason Carl, Waters, Guy William, Tran, Loan Phuong, Jensen Overgaard, Rasmus
• Granted Patent: US 9,834,792 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: C12M 23/58 Reaction vessels connected in series or in parallel combinations of bioreactors with other apparatus, C12M43/00
• CPC Class Codes: C12M 29/18 External loop; Means for reintroduction of fermented biomass or liquid percolate loop type reactors for chemical or physical processes B01J19/2435
• CPC Class Codes: C12P 7/04 acyclic
• CPC Class Codes: C12P 7/14 Multiple stages of fermentation; Multiple types of microorganisms or re-use of microorganisms
• CPC Class Codes: C12P 7/18 polyhydric
• CPC Class Codes: C12P 7/28 Acetone-containing products
• CPC Class Codes: C12P 7/54 Acetic acid vinegar C12J
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

Multi-stage, biological processes and systems for converting a C1 carbon source to desired end products are described. The processes comprise dividing a gaseous C1-containing substrate, in parallel, among multiple bioreactor stages. Liquid products are successively fed, in series, from a first bioreactor stage to downstream bioreactor stages. Operation can be simplified by avoiding the requirement for microorganism separation and recycle at each stage. In addition, overall vapor-liquid mass transfer for the combined stages is very favorable, leading to high end product productivity with comparably low byproduct metabolite productivity.

Claims

1. A multi-stage process for converting C1 carbon source into an end product, the process comprising:

feeding a gaseous C1-containing substrate, in parallel, to a first bioreactor stage and at least a second bioreactor stage of the multi-stage process,

feeding at least a portion of a first stage liquid product, in series, from the first bioreactor stage to the second bioreactor stage,

wherein the first stage liquid product comprises a C1-fixing microorganism used in the first bioreactor stage to metabolize C1-carbon source and generate the end product.

2. The process of claim 1, wherein the first stage liquid product is fed to the second bioreactor stage, without separation of the C1-fixing microorganism and recycle of separated C1-fixing microorganism to the first bioreactor stage.

3. The process of claim 1, comprising at least four bioreactor stages in which the gaseous C1-containing substrate is fed in parallel to the stages, and liquid products, including the first stage liquid product, are fed successively from the first bioreactor stage to a final bioreactor stage, and then withdrawn from the final bioreactor stage.

4. The process of claim 3, wherein an overall C1 utilization of the at least four bioreactor stages is at least about 60%.

5. The process of claim 3, wherein a final stage liquid product, following its withdrawal from the final bioreactor stage, is passed to an adjustable elevation that governs the liquid level in each bioreactor stage.

6. The process of claim 3, wherein the at least four bioreactor stages are operated at a pressure of less than about 200 kilopascal (kPa) above atmospheric pressure.

7. The process of claim 1, wherein the end product is ethanol and, in addition to ethanol, the C1-fixing microorganism generates acetic acid as a metabolite.

8. The process of claim 7, further comprising withdrawing a final stage liquid product from a final bioreactor stage of the multi-stage process, wherein a biomass free liquid fraction of the final stage liquid product comprises at least about 50 grams per liter (g/l) of ethanol.

9. The process of claim 8, wherein the biomass free liquid fraction of the final stage liquid product has an ethanol:

acetic acid weight ratio of at least about 50;

1.

10. The process of claim 1, wherein the end product is a growth dependent product selected from the group consisting of isopropanol, butanol, acetate, acetone, 2-hydroxyisobutyric acid and isobutylene

11. The process of claim 10, further comprising withdrawing a final stage liquid product from a final bioreactor stage of the multi-stage process, wherein a biomass free liquid fraction of the final stage liquid product comprises at least about 10 grams per liter (g/l) of isopropanol.

12. The process of claim 1, wherein the first and second bioreactor stages have at least one independently controllable process operating variable selected from the group consisting of liquid culture medium addition rate, gaseous C1-containing substrate feed rate, reactor temperature, reactor pH, and combinations thereof.

13. The process of claim 1, wherein at least one of the first and second bioreactor stages comprises a bioreactor having a ratio of its length to its width of less than about 10:

1.

14. The process of claim 1, wherein at least one of the first and second bioreactor stages comprises a circulated loop bioreactor.

15. The process of claim 14, wherein the circulated loop bioreactor operates with internal liquid circulation in a continuous liquid phase zone.

16. The process of claim 15, wherein, in the continuous liquid phase zone, liquid flows upward in an internal riser and downward in one or more internal downcomers.

17. The process of claim 15, wherein the circulated loop bioreactor operates with countercurrent gas and liquid flows in a continuous vapor phase zone, above the continuous liquid phase zone.

18. The process of claim 17, wherein the continuous liquid phase zone is within a bottom 75% of the length of the circulated loop bioreactor.

19. The process of claim 17, wherein the continuous liquid phase zone and continuous gas phase zone comprise vapor-liquid contacting devices, wherein continuous liquid phase zone devices differ from continuous vapor phase zone devices.

20. The process of claim 17, wherein liquid product, recycled through an external recycle loop, is to the continuous vapor phase zone.

21. The process of claim 20, wherein the liquid product that is recycled through the external recycle loop, is passed through an external heat exchanger for control of the temperature of the circulated loop bioreactor.

22. The process of claim 20, wherein a basic neutralizing agent is added to the liquid product that is recycled through the external recycle loop, to control the pH of the circulated loop bioreactor.

23. A multi-stage system, comprising

a plurality of bioreactors, comprising a gas inlet at a first end and a gas outlet at a second end opposite the first end, wherein the gas inlets and outlets allow feeding a gaseous C1-containing substrate to the plurality of bioreactors and removing gaseous products including unconverted C1 carbon source, in parallel;

wherein the bioreactors, but not a first bioreactor or a final bioreactor, comprise separate liquid inlets and outlets, proximate their respective first ends, for receiving an upstream liquid product, including biomass, from an adjacent, upstream bioreactor and conveying a liquid product, including biomass, to an adjacent, downstream bioreactor, in series; and

a liquid product outlet for receiving a final stage liquid product from the final bioreactor, proximate its first end.

24. The system of claim 23, wherein the liquid product outlet is in fluid communication with a siphon breaker that is adjustable in height, relative to the height of the bioreactors.

25. The system of claim 23, wherein the gas inlets are in fluid communication with gas spargers within the plurality of bioreactors, proximate their first ends.

26. The system of claim 23, wherein the plurality of bioreactors comprise external recycle loops for recycling liquid withdrawn proximate the first ends of the bioreactors to liquid distributors in continuous vapor phase zones, proximate the second ends of the bioreactors.

27. The system of claim 26, wherein the external liquid recycle loops are in fluid communication with basic neutralizing agent inlets and comprise instrumentation for independently controlling pH within the plurality of bioreactors.

28. The system of claim 26, wherein the external liquid recycle loops are in fluid communication with heaters or heat exchangers and comprise instrumentation for independently controlling temperatures within the plurality of bioreactors.

29. A multi-stage, biological process for converting CO to ethanol, the process comprising:

dividing a gaseous CO-containing substrate, in parallel, among a plurality of bioreactor stages of the multi-stage process;

successively feeding liquid products comprising carboxydotrophic microorganism, in series, from a first bioreactor stage to downstream bioreactor stages,

withdrawing, from a final bioreactor stage, a final stage liquid product having a non-carboxydotrophic microorganism containing liquid fraction comprising at least about 50 grams per liter (g/l) of ethanol and having an ethanol;

acetic acid weight ratio of at least about 50;

1.

30. The process of claim 29, comprising at least four bioreactor stages.

31. The process of claim 29, wherein two or more of the plurality of bioreactor stages are separate sections within a single vessel.