This invention relates to an apparatus for carrying out biochemical processes using fluids of different viscosity, particularly when culturing the tissue cells and microorganisms in nutrient media of high viscosity or liquids having a viscosity which changes (increases) during the mixing and can be used in various industries, particularly in biotechnology and food production.
A bioreactor is disclosed in prior art. Said bioreactor comprises a cylindrical tank with a lid and pipes for the supply and removal of gas, and a device for aerating and mixing the medium. The device for aerating and stirring comprises a horizontal bladed wheel fixed to the vertical drive shaft and placed in the upper part of the tank directly below the lid. The device also comprises an annular plate located beneath the wheel; said plate having a central opening for the passage of gas is peripherally attached to the tank wall to form an annular cavity around the wheel for inflow and outflow of gas. There are slotted openings in an annular baffle formed for passage of gas. The slotted openings are arranged uniformly around the circumference obliquely to the horizontal plane (WO 9205245).
The design of the bioreactor does not provide effective mixing of viscous culture medium in the biochemical processes. At high gas velocities, droplets with cultured cells are captured from the surface of the medium and thrown onto the tank wall resulting in injury and death of the cells.
Another bioreactor is disclosed in prior art. Said bioreactor comprises a cylindrical tank with a lid, a device for mixing a medium disposed in the tank, said device consisting of a bladed wheel mounted horizontally on a vertical shaft in the upper part of the tank, and an annular baffle arranged rotatable in the tank forming a gap with the tank wall and provided with floats. The bioreactor also comprises an annular baffle position adjusting mechanism fir adjusting the height of the annular baffle relative to the stirred medium. This mechanism can contain racks attached to the tank lid and the annular baffle with clamps. Said racks allow changing the position of the baffle relative to height of the tank (RU 2099413 C1).
The disadvantage of the bioreactor is in that when the annular baffle is fixedly attached, large resistance to the movement of the viscous medium is created thereby impairing the process of mixing. Use of the floating annular baffle leads to its ejection onto the surface of the liquid and periodical vibration displacing it to the tank wall thereby deteriorating the mixing process.
The closest analog of the claimed invention is a bioreactor according to RU 2299903 C2, which comprises a cylindrical tank with a lid, a device for mixing a medium, said device comprising a bladed wheel horizontally fixed to a vertical shaft in the upper part of the tank, and an annular baffle rotatably arranged in the tank so that it forms a clearance with the tank wall. The baffle is provided with floats. The device also comprises a position adjusting mechanism for adjusting the annular baffle surface height relative to the stirred medium. This mechanism includes a vertical rod mounted along the axis of the tank, and a bushing attached to the rod and connected to the annular baffle by means of racks for its rotation round the rod. Said adjusting annular baffle position mechanism can be provided with a locking element to fix its position relative to the rod, said locking element comprising an additional bushing disposed between the rod and the bushing of the annular baffle, and the limiting stops of the baffle and at least one clamping element, wherein the rod is installed with the possibility of its axial displacement.
However, said reactor operates in liquid media having a viscosity not grater than 2 times the viscosity of water. When higher viscous media are used, the speed of the activator wheel should be significantly increased to create higher pressure over the surface of the stirred liquid. When this occurs, droplets with cultured cells are captured and thrown on the tank wall, resulting in cell injury and death. In addition, in such case in a viscous liquid the central up flow (axial counter flow) is not formed at the bottom of the reactor tank but somewhat higher, thereby a stagnant zone is formed.
Furthermore, when culturing plant and animal cells that are prone to agglomerate, especially in viscous media or in media with varying viscosity, there is the problem of cell or cell cluster settling on the upper surface of the annular baffle. In further development of anchored cell agglomerates death of cells in lower layers and poisoning of the environment by lysis products occur adversely affecting the results of the cultivation.
The technical result of the invention is to increase mixing efficiency and to accelerate biochemical processes in liquid media.
This result is achieved due to the claimed bioreactor comprising a cylindrical tank with a lid, a stirring device located in the tank, said stirring device consisting of a bladed wheel fixed horizontally on a vertical shaft in the upper pad of the tank, and a horizontal annular baffle arranged in the tank with a gap relative to the cylindrical tank wall, a rod vertically mounted along the tank axis, wherein the rotatable horizontal annular baffle and the locking mechanism of the horizontal annular baffle are attached to said rod. According to the claimed invention, the bioreactor is provided with a pipe or a telescopic pipe fitting, an axial opening of the horizontal annular baffle, attached to the baffle from below, and passing around the rod. The horizontal annular baffle is configured with radial channels passing from the axial opening to the edge of the annular baffle with a slope downwards towards the tank bottom.
A horizontal annular baffle is configured floating. It can be made for example of polypropylene. The inner diameter of the pipe or the telescopic pipe fits the diameter of the axial opening of the horizontal annular baffle.
The area of the axial opening of the horizontal annular baffle is equal to the total areas of cross sections at the inlets of the radial channels and the total cross-sectional areas at the outlet of the radial channels.
A mechanism adjusting position of the horizontal annular baffle comprises a bushing rotatably mounted on the rod above the horizontal annular baffle and attached to the latter by means of struts, and elements for limiting axial movement of the bushing along the rod.
The walls, the tank lid, and the horizontal annular baffle of the bioreactor can be made of an optically transparent material, for example of polycarbonate.
The invention is illustrated by the following drawings.
The bioreactor (
On the upper surface 11 of the horizontal annular baffle 9 (
Moreover, a horizontal annular baffle 9 can be floatable if it is made of such material as for example polypropylene.
The annular partition 9 is provided with a mechanism for adjusting its position on the rod 10, said mechanism comprises a bushing 16 mounted on the rod 10 above the horizontal annular partition 9 and is rotatably attached to the latter by means of struts 17, and the elements 18 for limiting axial movements of the bushing 16 along the rod 10. The bioreactor is provided with a pipe 19 for mixing and aerating liquids having normal viscosity (close to the viscosity of water) or a higher viscosity (
The bioreactor is provided with a telescopic pipe 20 for mixing and aerating liquids having high viscosity (
Cultivation of Bacteria Animal or Plant Cells
When culturing microorganisms such as bacteria or animal or plant cells, the cylindrical tank 1 with horizontal annular baffle 9 and pipe 19 attached to the rod 10 (
Biotechnological Processes with Stirring Highly Viscous Liquids in a Vortex Bioreactor.
When stirring liquids of high viscosity, for example for hydrolysis of starch for producing starch syrup, before starting the process, an annular baffle 9 with a telescopic pipe 20 is attached to the rod 10 (Fig, 2). The lower end of the telescopic pipe 20 extends close to the bottom of the lank 1 at the annular perforated pipe 23 for supplying additional aerating eras. Next, the tank 1 is filled with starch suspension through the pipe 5 so that the surface of the liquid in the upper part of the tank 1 allows a cavity for movement of gas, and the annular baffle 9 is disposed in a medium with the surface 13 above the surface of the liquid medium, as shown in
Cultivation of Microalgae or other Photosynthetic Microorganisms.
A bioreactor used for culturing photosynthetic microalgae has the cylindrical wall of the tank 1, the lid 2 and the horizontal annular baffle 9 made of an optically transparent material such as polycarbonate.
Light sources are mounted on the outside of the transparent lid 2 (not shown in the Figures). Under sterile conditions, the cylindrical tank 1 with the horizontal annular baffle 9 with the tube 19 attached to the rod 10 is filled with the nutrient medium through the pipe 5 so that the surface of the medium in the upper part of the tank 1 leaves a cavity for the passage of the aerating gas, and the annular baffle 9 is located in a nutrient medium with the surface 13 above the liquid medium as shown in
The annular baffle 9 with the pipe 19 rotates in the same direction and with the same angular velocity as the culture liquid, and it is maintained at the rod 10 by its own buoyancy and the hold elements 18. During culturing, the annular baffle 9 with the pipe 19 increases the intensity of the liquid circulation (in the form of a tangential whirling motion with axial counterflow). The liquid medium with microalgae rises as upstream through the pipe 19 and the axial opening 13 of the baffle 9, and flows through the inclined radial channels 12 of the baffle 9 downwards along the cylindrical sidewalls of the tank 1. The inclined shape of the radial channels 12 of the annular baffle 9 does not allow microalgae settling on the surface of the baffle. Said microalgae are thrown off the baffle 9 by the liquid flow.
During the culturing, when applying the mixture of air and carbon dioxide through the feed pipe 6 for aerating gas and the perforated annular pipe 23, carbon dioxide is gripped by microalgae passing through the pipe 19 with the riser flow of the liquid. As a result of such aeration, the process of carbon dioxide consumption by microalgae, oxygen evolution, and breeding the culture are intensified. Absence of a traumatic stirring device inside the liquid allows cultivation of shell-less types of microalgae sensitive to mechanical stress. The speed of movement of the gas vortex (3-6 ms) does not cause separation of culture liquid droplets from the surface, which also reduces injury of the microalgae. Adjusting intensity of upstream and downstream flows of the microalgae suspension using activator of the bladed wheel 7, it is possible to passing all liquid layers with microalgae under the light source providing required mode of consumption of light photons. Cultivation takes place without formation of dead zones when the height of the medium in the tank 1 is equal to or several times (2-3 times) bigger than the tank diameter, while providing optimal conditions for cultivation of all types of microalgae. The process is carried out while the biomass grows, for example of Chlorella algae, to 15-20 g per 1 liter of the suspension. The resulting biomass is discharged through the pipe 5.
Thus, the claimed bioreactor can effectively stir liquids of various viscosity, including highly viscous liquids with simultaneous aeration without stagnant zones, and accelerate the biochemical processes in it.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/RU2011/000612 | 8/15/2011 | WO | 00 | 4/17/2014 |