Low-power bioreactor

Abstract

In conventional bioreactors consisting of a stirring device and aeration device, there was a risk of damaging bacterial strains and cells when microbubbles were supplied. [Solution] The low-power bioreactor of the present invention is characterized by comprising a tank in which a culture and a culture medium are contained, a stirring means provided in the tank, and a means for aerating only the culture medium without a culture. Furthermore, the means for aerating only the culture medium without a culture is characterized by comprising a circulation pipe provided in the tank for introducing the liquid in the tank and returning it to the tank for circulation, a liquid transfer means for transferring the liquid in the circulation pipe, a ventilation means provided in the circulation pipe, and a culture separation device provided in the circulation pipe upstream of the ventilation means for introducing only the culture medium without a culture into the portion of the circulation pipe where the ventilation means is provided.

Description

Technical Field

[0001] The present invention relates to a low-power bioreactor, and in particular to a bioreactor (biochemical reaction device) composed of a stirring device and an aeration device, which is used for culturing cultures such as microorganisms, animal and plant cells, and bacterial cells in a medium such as a culture solution.

Background Art

[0002] Conventionally, in large-volume aeration bioreactors for applications such as microbial culture that require a high OTR (Oxygen Transfer Rate), it has been common practice to aerate a large volume of gas (air) into the culture tank and forcibly disperse the air using turbine blades.

[0003] For this reason, the stirring power for dispersing gas results in a high energy consumption per unit volume Pv value of 2 to 3 kW / m 3 , and in addition, the power consumption of the blower for large-volume aeration is also high. As the culture volume increases with scale-up, there has been an increasing demand for reducing the power consumption of these devices.

[0004] In response to this, turbine blades with high gas dispersion efficiency and high liquid fluidity have been developed. However, in recent years, as larger bioreactors are desired, further improvement in efficiency and reduction in power consumption have become indispensable.

[0005] To achieve this, we have developed and commercialized a low-power bioreactor that combines a low-power stirring system (RB mixing system) with an aeration device that generates microbubbles with high aeration efficiency (Patent Document 1).

[0006] The low-power bioreactor enables circulation of liquid in the tank with low power consumption by means of a rotating blade at the upper part inside the tank and a stationary blade fixed to the bottom. Further, by introducing microbubbles generated by a microbubble generator provided in a circulation pipe connected to the outer side surface of the tank into the tank to the liquid circulating in the tank, the gas dispersion efficiency is improved with low power consumption.

Prior Art Documents

[0007] [Patent Document 1] Japanese Patent Publication No. 2024-74193 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, in this low-power bioreactor, the effect of bubble size is significant, and the use of even finer bubbles, UFB (ultrafine bubbles) (bubbles with a diameter of less than 1 micrometer (μm)), is desirable. However, since the pressure in the UFB generation field is higher than that inside the tank, there is a serious problem that cultured materials such as bacterial strains and cells in the tank will be damaged by this pressure change when they pass through this high-pressure field and return to the tank.

[0009] This invention solves the aforementioned problems. [Means for solving the problem]

[0010] The low-power bioreactor of the present invention comprises a tank in which a culture and a culture medium are contained, a stirring means provided in the tank, and a means for aerating only the culture medium without a culture, the means for aerating only the culture medium without a culture comprising a circulation pipe provided in the tank, which is equipped with a liquid transfer means for introducing the liquid in the tank and returning it to the tank for circulation, an aeration means provided in the circulation pipe, and a portion of the circulation pipe provided with the aeration means within the tank, which contains the culture Without letting it pass through, The stirring means comprises a membrane filter for introducing only the culture medium, and is characterized by comprising a rotating blade that discharges the liquid radially outward, and a stator vane consisting of a plurality of radially extending strip-shaped plates fixed to the bottom of the tank below the rotating blade.

[0011] Also, The aforementioned circulation pipe is characterized by being used for cooling, heating, concentration, or dilution.

[0013] Furthermore, the fine bubbles released from the ventilation means are characterized by being UFB (Ultra-Fluid Bubble).

[0014] Further, the culture separation means is characterized by being a centrifugal separator.

[0016] Further, the present invention is characterized by comprising backwashing means for backwashing the membrane filter.

[0017] Further, the means for ventilating only the culture medium free of the culture is characterized by comprising: a culture medium supply pipe for supplying the culture medium into the tank; a culture medium discharge pipe for discharging the culture medium from the tank; and a ventilation means provided in the culture medium supply pipe.

[0018] Further, the stirring means is characterized by comprising: a rotating blade that discharges liquid outward in a radial direction; and stationary blades fixed to the bottom of the tank below the rotating blade, the stationary blades extending radially and comprising a plurality of strip-shaped plates. Effects of the Invention

[0019] According to the present invention, a culture in a stirring tank can be cultured with low power.

[0020] Further, the influence on cells and the like can be reduced. Brief Description of the Drawings

[0021] [Figure 1] It is a longitudinal sectional side view for explaining the low-power bioreactor of the present invention. [Figure 2] It is an enlarged cross-sectional plan view for explaining the low-power bioreactor of the present invention. [Figure 3] It is a longitudinal sectional side view for explaining the low-power bioreactor of the present invention. [Figure 4] It is a longitudinal sectional side view for explaining another embodiment of the low-power bioreactor of the present invention. [Figure 5] It is a longitudinal sectional side view for explaining the low-power bioreactor according to a second embodiment of the present invention. Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0023] The low-power bioreactor of the present invention is constituted by a tank for accommodating a culture and a medium, a stirring means provided in the tank, and a means for aerating only a culture-free medium, thereby realizing culture of cultures such as cells with reduced damage to the cultures.

Examples

[0024] The low-power bioreactor according to the first embodiment of the present invention comprises, for example, as shown in FIG. 1 and FIG. 2, a bottomed cylindrical stirring tank 1 (or culture tank 1, the same applies hereinafter) for accommodating contents consisting of a culture and a medium for the culture, a rotating shaft 2 vertically disposed in the stirring tank 1, a stirring blade 3 provided on the rotating shaft 2 for discharging liquid radially outward, a stationary vane 4 provided at the bottom 1a of the stirring tank 1 below the stirring blade 3 for generating an upward flow, a liquid circulation pipe 5 connected to the outer peripheral wall of the stirring tank 1, for example in the vertical direction, with its upper and lower ends 5a and 5b communicating the inside and outside of the tank, a liquid transfer means such as a pump (not shown) provided on the liquid circulation pipe 5 for transferring the liquid in the liquid circulation pipe 5, an aeration means 6 provided in the liquid circulation pipe 5, and a culture separation device 7 provided in the liquid circulation pipe 5 upstream of the aeration means, which does not introduce cultures but only introduces the medium into the liquid circulation pipe section provided with the aeration means.

[0025] The stirring blade 3 is composed of, for example, blade plates 3a such as four rectangular flat paddle blades radially fixed in the radial direction to the lower end of the rotating shaft 2 provided at the center of the stirring tank 1, and is provided at the upper part of the stirring tank 1 near the liquid surface in the liquid.

[0026] Furthermore, the stationary vanes 4 are composed of a plurality of linear strip plates 4a of the same shape provided at the center of the bottom 1a of the stirring tank 1, as shown in FIG. 2 for example. Four of the strip plates 4a are radially fixed in parallel to a position spaced by a distance d from a radial line R passing through the center of the bottom 1a in the stirring tank 1 below the stirring blade 3, for example, four pieces are fixed, and a gap is formed at the center of the bottom corresponding to the intersection of these strip plates 4a.

[0027] Then, as shown in Figure 3, the stirring blades 3 and the stationary blades 4 cause the liquid in the stirring tank 1 to circulate with low power by a downward swirling flow along the inner circumferential surface 1b of the stirring tank 1 and an upward flow generated in the center.

[0028] Furthermore, the ventilation means 6 consists of a ventilation nozzle for discharging fine bubbles, and a microbubble discharge means consisting of a ceramic porous body or a microbubble membrane.

[0029] Then, the ventilation means 6 releases, for example, ultrafine bubbles (UFB) with a diameter of less than 1 micrometer (μm) into the liquid circulation tube 5.

[0030] Furthermore, in order to minimize the impact on the culture medium in the stirring tank 1, it is preferable that the microbubble release means be provided at a position away from the inlet end 5a and the outlet end 5b of the liquid circulation pipe 5.

[0031] For example, considering the flow within the liquid circulation pipe 5, a position slightly away from the inlet end 5a on the upstream side of the liquid circulation pipe 5 is preferable.

[0032] Furthermore, the culture separation device 7 may include, for example, a membrane filter provided at the inlet end 5a of the liquid circulation pipe 5 that allows only the culture medium to pass through (be introduced) into the liquid circulation pipe 5, while preventing the culture from passing through (be introduced), or a centrifugal separation means that returns the culture to the stirring tank and introduces only the culture medium into the liquid circulation pipe 5.

[0033] Furthermore, the liquid circulation pipe 5 may be provided with a means for circulating the liquid in the reverse direction using a pump or the like, and a backwashing means for backwashing the membrane filter may be provided.

[0034] Because the present invention has the above configuration, when the stirring blade 3 is rotated, as shown in Figure 3, the liquid from the stirring blade 3 is discharged radially outward, hits the inner circumferential surface 1b of the stirring tank 1, creates a downward swirling flow along the inner circumferential surface of the stirring tank 1, reaches the bottom 1a, moves to the center of the bottom 1a, and creates an upward flow at the center by the stationary blade 4 of the bottom 1a, and the rising liquid is discharged radially outward by the stirring blade 3, so that the liquid circulates in the stirring tank 1 with low power.

[0035] Furthermore, when the pump is driven, the culture is separated from the contents of the stirring tank 1 by the culture separation device 7, and only the culture medium without the culture is introduced into the liquid circulation pipe 5 from the inlet end 5a of the liquid circulation pipe 5. Then, microbubbles are released into the culture medium by the microbubble release means, aeration occurs, and the culture medium is then discharged into the stirring tank 1 from the outlet end 5b of the liquid circulation pipe 5 by the driving force of the pump.

[0036] Furthermore, since the cultured material does not pass through the high-pressure field near the UFB, damage can be prevented.

[0037] According to the present invention, the rotor blade 3 and stator blade 4 allow for stirring of the contents of the stirring tank with low power.

[0038] Furthermore, by using microbubbles, the required ventilation power can be reduced.

[0039] Furthermore, even when UFB is released, the impact on cells and other tissues can be minimized.

[0040] Achieving this will enable more efficient cultivation with lower power consumption, making the planned scaling up to 300kL to 500kL in recent years a realistic possibility.

[0041] In the above embodiment, the liquid circulation tube 5 simply circulated the liquid in the culture tank, but the liquid circulation tube may also be a circulation tube for cooling, heating, concentration, dilution, addition, crystallization, etc.

[0042] The liquid circulation pipe 5 may also be provided inside the stirring tank 1.

[0043] Furthermore, the liquid circulation pipe 5 may be connected to the stirring tank 1 in a horizontal or other direction, in addition to being connected vertically, and there are no particular limitations on the location of connection.

[0044] Furthermore, multiple liquid circulation tubes 5 may be provided, and the culture separation device 7 is provided in the liquid circulation tube equipped with a ventilation means.

[0045] Furthermore, the means for transferring the liquid within the liquid circulation pipe may be other than a pump.

[0046] In the above embodiment, an example with stationary vanes 4 was shown. However, since the main objective of the present invention is to prevent damage to cultured substances such as cells, in addition to low power consumption, as shown in Figure 4, the tank may be stirred simply by a stirring means consisting only of rotor blades 3, without providing stationary vanes 4. [Examples]

[0047] In a second embodiment of the present invention, the invention is applied to a culture apparatus for continuously culturing cultures. The culture apparatus (bioreactor), as shown in Figure 5, for example, comprises a culture tank 1, a culture medium supply pipe 8 for supplying culture medium into the culture tank 1, and a culture medium discharge pipe 9 for discharging culture medium outside the culture tank 1. A ventilation means 6 is provided inside the culture medium supply pipe 8.

[0048] Furthermore, the culture tank 1 is provided with a blade stirring mechanism, for example, consisting of a stirring blade 3 and a stationary blade 4.

[0049] Furthermore, the stirring means may omit the stationary blades 4 and consist only of the stirring blades 3. Alternatively, it may be a vertically reciprocating stirring means.

[0050] Note that the same reference numerals are used for parts that are the same as in Example 1, and their descriptions are omitted.

[0051] Then, for example, after culturing the culture while stirring the contents of the culture tank 1 with the stirring means, or while culturing, the culture medium discharge pipe 9 is sucked out with a suction pump or the like, and only the culture medium containing waste products in the culture tank 1 is extracted to the outside of the culture tank 1 via a filter or the like. At the same time, fresh culture medium that has been aerated by the ventilation means is supplied into the culture tank 1 through the culture medium supply pipe 8, thereby exchanging the culture medium and allowing aeration to be performed on the contents of the tank.

[0052] Furthermore, when the stirring blade 3 and the stationary blade 4 are used, the flow of liquid in the stirring tank 1 will circulate within the tank by a swirling flow and an upward flow, similar to Figure 3 of Embodiment 1.

[0053] In the second embodiment of the present invention, since the culture medium without culture material is aerated, the culture material such as cells is not damaged. [Explanation of symbols]

[0054] 1. Agitation tank 1a bottom 1b Inner surface 2 rotation axes 3. Agitator blades 3a wing plate 4 Static Wings 4a Strip-shaped plate 5 Liquid circulation pipe 5a Upper end 5b Lower end 6. Ventilation means 7. Culture Isolation Device 8. Culture medium supply tube 9. Culture medium discharge tube

Claims

1. A tank in which the culture material and culture medium are placed, A stirring means provided inside the tank, A means of aerating only the culture medium that does not contain culture material and More The means for aerating only the culture medium without the culture material is, A circulation pipe is provided in the tank, which is equipped with a liquid transfer means for introducing the liquid in the tank and returning it to the tank for circulation. A ventilation means provided in the aforementioned circulation pipe, The chamber contains a membrane filter installed at the inlet end of the circulation pipe within the tank, which is provided with the ventilation means to introduce only the culture medium without allowing the culture material to pass through. The stirring means includes a rotating blade that discharges the liquid radially outward, A low-power bioreactor characterized by comprising a stator vane consisting of a plurality of radially extending strip-shaped plates fixed to the bottom of the tank below the rotor blade.

2. The low-power bioreactor according to claim 1, characterized in that the circulation pipe is for cooling, heating, concentration, or dilution.

3. The low-power bioreactor according to claim 1, characterized in that the microbubbles released from the ventilation means are UFBs.

4. The low-power bioreactor according to claim 1, further characterized by being provided with a backwashing means for backwashing the membrane filter.

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