Solid state fermentation

• US 6,197,573 B1
• Filed: 11/17/1998
• Issued: 03/06/2001
• Est. Priority Date: 11/17/1998
• Status: Expired due to Term

• Current Assignee: Biocon India Limited
• Original Assignee: Biocon India Limited
• Inventors: Suryanarayan, Shrikumar, Mazumdar, Kiran
• Primary Examiner(s): Redding, David A.
• Application Number:
  US09/193,384
• Time in Patent Office: 840 Days
• Field of Search: 435/286.7, 435/289.1, 435/291.1, 435/291.3, 435/291.6, 435/293.2, 435/294.1
• US Class Current: 435/286.7
• CPC Class Codes: A61L 2/07 Steam
• CPC Class Codes: C12M 21/16 Solid state fermenters, e.g. for koji production
• CPC Class Codes: C12M 23/04 Flat or tray type, drawers C12M23/10, C12M23/12, C12M23/16 take precedence
• CPC Class Codes: C12M 23/20 Material Coatings immunocoatings C12M25/00
• CPC Class Codes: C12M 23/44 Multiple separable units; Modules
• CPC Class Codes: C12M 27/02 Stirrer or mobile mixing elements
• CPC Class Codes: C12M 37/00 Means for sterilizing, maintaining sterile conditions or avoiding chemical or biological contamination C12M23/38 takes precedence; filtration in general and filters per se B01D24/00-B01D41/00; autoclaves B01J3/04; treatment of microorganisms with electrical or wave energy C12N13/00
• CPC Class Codes: C12M 41/22 in contact with the bioreactor walls

Abstract

The present invention provides an improved solid state fermentation device that combines all of the operations of microorganism cultivation (sterilization, inoculation, cultivation, extraction, and post extraction treatment). This solid state fermentation device is modular in nature and operates in a contained manner so that the live microorganisms from the reactor cannot come into contact with the environment and pollute the environment and also so that the environment inside the bioreactor is aseptic. Another aspect of this invention allows fermentation of microorganisms without inhibiting the growth of the microorganism. Specifically, the bioreactor is designed to remove heat that accumulates inside the bioreactor during fermentation by conduction. Additionally, there is a mechanism to add fluid to the interior of the bioreactor that permits equal distribution and precise control of a variety of environmental parameters. For example, the bioreactor of the present invention provides a means to add nutritive media to the microorganisms at any time during the fermentation process without disturbing the fermenting microorganisms. Furthermore, the bioreactor of the present invention provides a mechanism to mix the contents of the bioreactor at any time and for any duration during the fermentation process. Finally, the present bioreactor provides a means of extracting desired microbial products from the bioreactor without opening the bioreactor.

Claims

1. A bioreactor for cultivating microorganisms on solid medium in such a manner that the bioreactor carries out all steps for cultivating microorganisms in a contained environment, wherein the bioreactor comprises:

a plurality of modules, the modules capable of being fitted on top of one another to form a stack of modules, wherein each module comprises;

a base plate containing communicating and non-communicating channels; and

a frame mounted to the base plate of the module; and

a mixing arrangement placed within each module.

2. A bioreactor according to claim 1, wherein the bioreactor further comprises a means for sealing the microorganisms within the bioreactor to prevent exposure of the microorganisms to an external environment during operation of the bioreactor.

3. A bioreactor according to claim 1, wherein the bioreactor further comprises a means for controlling the environment of each module.

4. A bioreactor according to claim 1, wherein the bioreactor is made of stainless steel or polycarbonate.

5. A bioreactor according to claim 1, wherein the modules are fitted in such a manner to prevent leakage from within the modules to the outside environment.

6. A bioreactor according to claim 1, wherein the modules are fitted in such a manner to prevent outside contaminants from getting inside the module.

7. A bioreactor according to claim 1, wherein the modules are fitted together by sealing with rubber gaskets.

8. A bioreactor according to claim 1, wherein the dimensions of the module and the size of the stack can be adjusted.

9. A bioreactor according to claim 1, wherein a multiplicity of stacks of modules are operated in parallel.

10. A bioreactor according to claim 1, wherein the modules are a multiplicity of shapes.

11. A bioreactor according to claim 1, wherein the modules are square in shape.

12. A bioreactor according to claim 8, wherein the communicating and non-communicating channels alternate with one another.

13. A bioreactor according to claim 1, wherein the modules are circular in shape.

14. A bioreactor according to claim 7, wherein the communicating and non-communicating channels are arranged radially.

15. A bioreactor according to claim 7, wherein communicating channels are branched for equal distribution of fluids to the module.

16. A bioreactor according to claim 1, wherein the communicating channels are tubes having holes drilled therein for allowing fluids to enter the interior of the module.

17. A bioreactor according to claim 1, wherein the non-communicating channels are tubes for carrying fluids.

18. A bioreactor according to claim 1, wherein the non-communicating channels are formed by spaces between the tubes that form the communicating channels for carrying fluids.

19. The bioreactor of claim 17 or 18, wherein the non-communicating channels carry heating and cooling fluids as a means for controlling the temperature of the modules by conduction.

20. A bioreactor according to claim 1, wherein the communicating channels carry a fluid.

21. A bioreactor according to claim 1, wherein the non-communicating channels carry a fluid capable of conducting heat.

22. A bioreactor according to claim 1, wherein the base plate comprises two metal sheets that sandwich the communicating and non-communicating channels.

23. A bioreactor according to claim 1, wherein the base plate does not have two metal sheets that sandwich the communicating and non-communicating channels.

24. The bioreactor of claim 22, wherein the two metal sheets have a multiplicity of holes drilled therein.

25. The bioreactor of claim 24, wherein the holes correspond to the holes drilled into the communicating channels such that fluids from the communicating channels can enter the interior of the module.

26. A bioreactor according to claim 1, wherein the frame mounted on the base plate forms a container for the solid medium in such manner that the solid medium is in contact with the base plate.

27. A bioreactor according to claim 1, wherein heat is removed from the bioreactor by conduction during cultivation.

28. A bioreactor according to claim 1, wherein the frame height is adjustable.

29. A bioreactor according to claim 1, wherein the frame height is 4-8 cm.

30. A bioreactor according to claim 1, wherein the mixing arrangement is placed at the center of the module for mixing the solid medium.

31. A bioreactor according to claim 1, wherein the mixing arrangement comprises at least two mixing arms.

32. A bioreactor according to claim 1, wherein the mixing arrangement comprises one mixing arm.

33. A bioreactor according to claim 32, wherein the mixing arms are equipped with blades.

34. A bioreactor according to claim 32, wherein the mixing arms are able to rotate.

35. A bioreactor according to claim 32, wherein the mixing arms are able to revolve about the central axis of the module.

36. A bioreactor according to claims 34 and 35, wherein the rotating and revolving are achieved by a two independent shafts.

37. A bioreactor according to claims 34 and 35, wherein the ratio of the speed of revolution to the speed of revolving is fixed to allow equal redistribution of the contents of the bioreactor.

38. A bioreactor according to claim 36, wherein the two independent shafts are driven by at least one independent motor.

39. A bioreactor according to claim 36, wherein the two independent shafts are driven by two independent motors.

40. A bioreactor according to claim 1, wherein the bioreactor further comprises a central distribution port.

41. A bioreactor according to claim 40, wherein the central distribution port is connected to the communicating channels as a means for delivering fluids to the communicating channels.

42. A bioreactor according to claim 40, wherein the central distribution port is a ring.

43. A bioreactor according to claim 1, wherein the bioreactor further comprises a header arrangement.

44. A bioreactor according to claim 43, wherein the header arrangement is connected to the non-communicating channels for bringing fluid into the non-communicating channels.

45. A bioreactor according to claim 1, wherein the bioreactor further comprises a collection port.

46. A bioreactor according to claim 45, wherein the collection port is connected to the non-communicating channels for collecting fluids leaving the non-communicating channels within the base plate.

47. A bioreactor according to claim 45, wherein the collection port is a ring which is concentric with the distribution ring and just inside of the central distribution port.

48. A bioreactor according to claim 47, wherein the diameter of the inner collection ring is larger than the diameter of the distribution ring, thereby allowing fluids coming into the non-communicating channels from the circular header at the periphery to slip over the distribution ring and flow into the collection port and out of the module through the collection ring.

49. A bioreactor according to claim 1, wherein the bioreactor further comprises alternating emitter and collector plates attached to each module of the bioreactor.

50. A bioreactor according to claim 49, wherein fluids enter the module through the emitter plates.

51. A bioreactor according to claim 49, wherein fluids leave the module through the collector plates.

52. A bioreactor according to claim 49, wherein the top emitter or collector plate has holes only in the bottom of the communicating channel and the bottom emitter or collector plate has holes only in the top of the communicating channel.

53. A bioreactor according to claim 49, wherein the emitter plates and collector plates have valves that can be closed such that fluids can be retained in the bioreactor.

54. A bioreactor according to claim 49, wherein the emitter plates and collector plates have valves that can be closed such that pressure inside the bioreactor increases.

55. A bioreactor according to claim 1, further comprising dished ends placed over the top plate and under the bottom plate.

56. A bioreactor according to claim 1, wherein the bioreactor further comprises auxiliary equipment for the operation of the bioreactor.

57. A bioreactor according to claim 1, wherein the bioreactor further comprises an apparatus for purifying an extracted product.

58. A system for solid state fermentation in a bioreactor for cultivating microorganisms in a contained environment, wherein the system comprises:

1) a bioreactor comprising;

A) a plurality of modules, the modules capable of being fitted on top of one another to form a stack of modules, wherein each module comprises;

a base plate containing communicating and non-communicating channels; and

a frame mounted to the base plate of the module; and

B) a mixing arrangement placed within each module; and

2) a solid state medium disposed in each module.

59. A system for solid state fermentation according to claim 58, wherein the solid state medium is selected from the group consisting of:

maize bran, corn, wheat, soya hull, soya beans, cereal, vermiculite, diatomaceous earth, and polyurethane foam.

60. A system for solid state fermentation according to claim 58, wherein the solid state medium is any support material capable of absorbing aqueous solutions.

61. A system for solid state fermentation according to claim 60, wherein the aqueous solution is a nutritive medium.

62. A system for solid state fermentation according to claim 58, and further comprising microorganisms disposed in each module.

63. A system for solid state fermentation according to claim 62, wherein the microorganisms are genetically modified.

64. A system for solid state fermentation according to claim 62, wherein the microorganisms are selected from the group consisting of bacteria, yeast and fungi.

65. A system for solid state fermentation according to claim 64, wherein the fungi is aseptate.

66. A system for solid state fermentation according to claim 64, wherein the fungi is septate.

67. A system for solid state fermentation according to claim 64, wherein the fungi is intracellular septate.

68. A system for solid state fermentation according to claim 64, wherein the fungi is extracellular septate.

69. A system for solid state fermentation according to claim 62, and further comprising a fluid disposed within the communicating channel, wherein the fluid is selected from the group consisting of:

steam, air, water, inoculum and organic solvent.

70. A system for solid state fermentation according to claim 62, and further comprising a fluid disposed within the non-communicating channel, wherein the fluid is steam, air, or water.