Bioreactor Equipment

Abstract

A bioreactor apparatus and method for bioreactor processing is disclosed. The bioreactor apparatus includes a vessel for containing liquid medium and headspace gas, and a venturi pump assembly. The venturi pump assembly includes a medium outlet conduit, a medium inlet conduit, a pump device configured to draw medium from the vessel through the medium outlet conduit and pass it through the medium inlet conduit, and a bubble trapping member. The bubble trapping member has a mouth portion disposed within the vessel at a liquid medium surface location and a narrowed throat portion. The medium inlet conduit is adapted to pass pumped medium through the throat portion of the bubble trapping member to create a reduced pressure region therein for drawing surface bubbles into the mouth portion of the bubble trapping member.

Description

[Technical field]

[0001] The present invention relates to a bioreactor apparatus and a method for treating a bioreactor medium. [Background technology]

[0002] Fermenters and bioreactors for facilitating and optimizing microbial reactions and processes are known in the art. Such bioreactors generally require mechanical movement of the liquid medium containing the microorganisms and active substances to address two main challenges: aerating the medium for microbial respiration, and mixing the contents throughout the container tank to achieve a uniform distribution of oxygen, nutrients, microorganisms, etc. In the bioreactors previously discussed, aeration is generally achieved by filtered sterile air pumped through a microbubble generator such as an air stone. Aeration is usually separate from the mixing system.

[0003] Aeration and / or mixing processes usually generate biological foam, which can lead to very significant volume loss and thus loss of bioreactor function. Because foam generation depends on several variables and is therefore unpredictable, chemical antifoam agents such as surfactants are routinely used. The yield of some reactor processes can be affected by such agents.

[0004] Bioreactor systems previously considered are very complex, have many moving parts, and are time-consuming and expensive to maintain and clean.

[0005] Filtration systems for headspace gases for bioreactors can be unreliable or behave differently in different environmental conditions, potentially affecting bioprocessing. Some environments in which bioreactors are required to operate are harsh for reactor components and require careful isolation. Some known sterilization systems require expensive and complex, or environmentally damaging or inefficient components or materials. Some known filtration systems require filters that must be replaced periodically once saturated with filtered materials. Such systems can be difficult or expensive to apply to various bioreactors or media, as different filters or filtration styles may be required. Other known systems use ultraviolet light for sterilization, but ultraviolet light is not always effective against all microorganisms. Known sterilization systems can also cause a significant reduction in air flow into the bioreactor environment. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention aims to address these challenges and to provide improvements over known devices and methods. [Means for solving the problem]

[0007] Aspects and embodiments of the invention are set out in the accompanying claims.

[0008] In general, one embodiment of a first aspect of the present invention can provide a bioreactor apparatus comprising: a container for containing liquid medium and headspace gas; a venturi pump assembly, the venturi pump assembly including a medium outlet conduit, a medium inlet conduit, a pump device configured to draw medium from the container through the medium outlet conduit and pass it through the medium inlet conduit; and a bubble trapping member including a mouth portion and a narrowed throat portion disposed within the container at a liquid medium surface location, the medium inlet conduit adapted to pass pumped medium through the throat portion of the bubble trapping member to create a reduced pressure region therein for drawing surface bubbles into the mouth portion of the bubble trapping member.

[0009] This allows air bubbles to be removed from the liquid medium surface by the air bubble trapping member and Venturi pump rather than requiring anti-foam agents or the like. Air bubbles can be aspirated, sucked or drawn into the mouth portion. The liquid medium may be sealed or contained by a container. The throat can be a constricted portion or area of ​​the trapping member and can provide or enable a Venturi effect. The liquid medium may or may not contain microorganisms.

[0010] Preferably, the medium inlet conduit is positioned to enter the mouth portion of the bubble trapping member and pass pumped medium through the throat portion.

[0011] In an embodiment, the pump device is located outside the container.

[0012] Optionally, the mouth portion is adapted to draw headspace gas into the mouth portion of the bubble trapping member in the direction of the pumped medium passing through the throat portion of the bubble trapping member while creating a reduced pressure region therein.

[0013] Suitably, the apparatus includes a mixing device for mixing any of the air bubbles, headspace gas and liquid medium from the air bubble trapping member. Optionally, the mixing device is located downstream of the air bubble trapping member. In an embodiment, the mixing device is fed from the air bubble trapping member by at least a first intermediate medium conduit. Suitably, the mixing device includes an impeller, the impeller adapted to draw any of the air bubbles, headspace gas and / or liquid medium into the mixing device and / or to atomize the mixture of any of the air bubbles, headspace gas and / or liquid medium.

[0014] This allows for a simplified system compared to previously considered systems, providing combined aeration and mixing as well as air bubble capture.

[0015] Optionally, the mixing device is disposed in line with the bubble trapping member.

[0016] Optionally, the mixing device is adapted to create a region of reduced pressure to draw the container contents into the mixing device.

[0017] One embodiment of another aspect of the present invention can provide a bioreactor apparatus including a container for containing liquid culture medium, a venturi pump assembly including a culture medium outlet conduit, a culture medium inlet conduit, a pump device configured to draw culture medium from the container through the culture medium outlet conduit and pass it through the culture medium inlet conduit, a bubble trapping member including a mouth portion and a narrowed throat portion, and a mixing device disposed downstream of the trapping member, wherein the culture medium inlet conduit is adapted to pass pumped culture medium through the throat portion of the trapping member to create a reduced pressure region therein for drawing the container contents into the mouth portion of the trapping member, and the mixing device is adapted to mix the container contents captured by the trapping member.

[0018] The series combination of a Venturi pump and a post-mixer provides more efficient mixing and aeration than previously considered systems and allows the Venturi pressure differential to be shared by two devices, reducing the shear load on the microorganisms in the bioreactor. The capture member can be positioned within the vessel at the liquid medium surface.

[0019] Suitably, the mixing device is fed from the collection member by at least a first intermediate medium conduit. Optionally, the mixing device comprises an impeller adapted to draw any of the gas bubbles, headspace gas and / or liquid medium into the mixing device and / or to atomize a mixture of any of the gas bubbles, headspace gas and / or liquid medium. In an embodiment, the pump device comprises a first drive means or modality and the mixing device comprises a second drive means.

[0020] Optionally, the device includes a dedicated air bubble trapping member, the dedicated air bubble trapping member including a mouth portion located at a liquid medium surface location opposite to the surface location of the air bubble trapping member.

[0021] In an embodiment, a dedicated bubble collection conduit is coupled to the dedicated bubble collection member and to the impeller housing, and the impeller is further adapted to create a reduced pressure region for drawing surface bubbles into a mouth portion of the dedicated bubble collection member.

[0022] Suitably, the apparatus of any of the above embodiments may include an environmental gas compressor and a first sterilisation unit operable to receive gas from the compressor, heat the gas to a predetermined sterilisation temperature, cool the gas to a predetermined container temperature and supply sterilised gas to the container.

[0023] Optionally, the dedicated bubble trapping member includes a narrowed throat portion.

[0024] Optionally, the pump device is located outside the container.

[0025] According to another aspect disclosed herein, there is provided a bioreactor apparatus comprising: a container for containing liquid culture medium and head space gas; a venturi pump assembly comprising a bubble trapping member having a mouth portion and a narrowed throat portion; a culture medium conduit disposed within the bubble trapping member concentrically with the narrowed throat portion; and a pump device configured to pump culture medium from the container through the culture medium conduit, thereby creating a reduced pressure region for drawing surface bubbles and / or head space gas into the mouth portion of the bubble trapping member.

[0026] Optionally, the bioreactor device may comprise any one or more of the features recited in claims 1 to 17 or any combination thereof.

[0027] One embodiment of another aspect of the present invention may provide a system for maintaining environmental conditions in a sealed chamber including an environmental gas compressor and a first sterilization unit operable to receive gas from the compressor, heat the gas to a predetermined sterilization temperature, cool the gas to a predetermined enclosure temperature, and supply sterilized gas to the sealed chamber.

[0028] This system can provide sterilization for a sealed chamber that is more efficient and comprehensive (removes more different microorganisms and contaminants) than in previously contemplated systems.

[0029] Suitably, the enclosed chamber is pressurised. Optionally, the enclosed chamber is a bioreactor.

[0030] In an embodiment, the first sterilization unit includes an intermediate chamber operable to receive gas heated to a predetermined sterilization temperature and output gas that is cooled to a predetermined enclosure temperature.

[0031] Preferably, the intermediate chamber comprises a coiled conduit having an inlet end for receiving the heated gas and an outlet end for producing the cooled gas. The coiled conduit may alternatively be helical or serpentine in shape.

[0032] The advantage of this configuration is that a high gas flow rate can be maintained into the sealed chamber and, due to the increased travel distance through the coiled conduit, the gas can be kept heated longer (or for a sufficient period despite the high flow rate) for improved sterilization while still maintaining a compact overall system structure.

[0033] Preferably, the system includes a second sterilisation unit operable to receive the gas from the sealed chamber and heat the gas, which may be to a predetermined sterilisation temperature.

[0034] Optionally, the second sterilisation unit is operable to heat the gas and then cool the gas to a predetermined ambient temperature.

[0035] An embodiment of another aspect of the invention can provide an apparatus including a container for containing a liquid medium and a venturi assembly including a medium outlet conduit, a medium inlet conduit, a pump device, and a trapping member including a mouth portion and a throat portion, the venturi assembly can be arranged to create a reduced pressure region for drawing surface air bubbles into the mouth portion of the trapping member.

[0036] An embodiment of another aspect of the present invention can provide an apparatus including a container for containing a liquid medium and a venturi assembly, the venturi assembly including a medium outlet conduit, a medium inlet conduit, and a pump device. The apparatus can include a mixing device. The venturi assembly can be arranged to create a reduced pressure region to draw the liquid medium into and / or through the venturi assembly and / or into or through the mixing device.

[0037] According to another aspect disclosed herein, there is provided a bioreactor system comprising the bioreactor apparatus as described above and a system for maintaining environmental conditions within the enclosed chamber as described above.

[0038] According to another aspect disclosed herein, there is provided a use of a bioreactor apparatus as described above and / or a system for maintaining environmental conditions within an enclosed chamber as described above.

[0039] According to another aspect disclosed herein, there is provided a method for bioreactor processing comprising the steps of providing a container for containing liquid culture medium and a venturia pump assembly including a culture medium outlet conduit, a culture medium inlet conduit, a pump device, an inlet member including a mouth portion and a throat portion, and a mixing device, drawing culture medium from the container through the culture medium outlet conduit using the pump device and passing it through the culture medium inlet conduit, passing the pumped culture medium through the throat portion of the inlet member to create a reduced pressure region therein for drawing the container contents into the mouth portion of the inlet member, and mixing the container contents collected by the inlet member using the mixing device.

[0040] Optionally, the method includes providing an environmental gas compressor and a sterilization unit, receiving gas from the compressor in the sterilization unit, heating the gas to a predetermined temperature, and supplying the sterilized gas to a container.

[0041] Optionally, the method includes the steps of providing an elongated heating portion, receiving an input gas, throttling the input gas using the elongated heating portion, heating the gas to a predetermined sterilization temperature using the elongated heating portion, and supplying the sterilized gas to the container.

[0042] The above aspects and embodiments may be combined to provide further aspects and embodiments of the invention.

[0043] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0044] [Figure 1a] FIG. 1 is a schematic diagram showing components of a bioreactor apparatus according to an embodiment of the present invention. [Figure 1b] FIG. 1 is a schematic diagram showing components of a bioreactor apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram of a bioreactor apparatus according to an embodiment of the present invention. [Diagram 3] FIG. 1 is a schematic diagram showing components of a bioreactor apparatus according to an embodiment of the present invention. [Figure 4] FIG. 1 illustrates components of a sterilization system according to an embodiment of the present invention. [Diagram 5] FIG. 1 illustrates components of a sterilization system according to an embodiment of the present invention. [Figure 6] FIG. 1 illustrates components of a sterilization system according to an embodiment of the present invention. [Figure 7] FIG. 1 illustrates components of a sterilization system according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Detailed Description of the Embodiments The apparatus and systems of the present invention embodiments allow for improved bioreactor efficiency, lower complexity, lower environmental impact, more reliable processing and improved or facilitated maintenance. The apparatus and systems of the present invention embodiments allow for improved aeration and mixing (improving microbial growth) and reduced shear loads (reducing or avoiding microbial damage or destruction). The use of eductor or venturi driven bubble trapping allows for the reduction or elimination of antifoam agents. Coordination of bubble trapping, aeration and mixing allows for simplified components and processing and can facilitate increased biomass content and growth rates. The use of a sealed and reliable sterilization and headspace gas control system allows for predictable results in any condition.

[0046] The use of eductor or venturi driven aeration allows for the reduction or elimination of antifoam agents. The combination of eductor or venturi driven aeration and air bubble trapping is particularly advantageous for allowing for the reduction or elimination of antifoam agents.

[0047] An example of an apparatus 100 according to an embodiment of the invention is shown in Figure 1. Within a bioreactor vessel (not shown), a liquid medium 106 containing the microorganisms for a given process is located below the headspace gas. Naturally, different processes require different medium components, microorganisms and headspace gas, typically air. Embodiments of the invention are applicable to a wide variety of processing paradigms.

[0048] In this case, bioprocessing generates gas bubbles 108, which sit on the surface of the liquid. The gas bubble collector 102 is positioned in the container so that its mouth sits on the liquid medium surface (or the liquid medium is filled or can be filled to this level). The gas bubble collector can also include an additional lateral inlet to overcome small differences in liquid level in the container when gas bubbles are generated (which would change the liquid level during the process). In one embodiment, the gas bubble collector can also compensate for larger liquid level differences by inclusion of a pressure-controlled floatation device attached to the upper edge of the gas bubble collector. In another embodiment, the gas bubble collector can also compensate for larger liquid level differences by a liquid level sensing integrated circuit that controls a mechanical height adjustment arm attached to the gas bubble collector.

[0049] In this embodiment, a venturi pump structure is used in conjunction with this air bubble trap to remove air bubbles from the liquid surface.

[0050] Alternatively, the bubble trapping member 102 may be positioned such that its mouth is near (but not exactly at) the liquid medium surface (or such that the liquid medium is filled or can be filled to this level).Those skilled in the art will appreciate that the bubble trapping member may function as a suction or trapping device.

[0051] In embodiments, the (air bubble) trapping member may be positioned or elevated above the liquid level so that only headspace gas (and not the liquid or air bubbles at the liquid level) is drawn into the trapping member at least in the initial processing stages. In embodiments, multiple trapping members may be used to perform different or complementary functions. For example, one trapping member may be used for aeration or for drawing headspace gas, and another for air bubble collection or liquid mixing. The trapping members may each perform a combination of these functions if appropriately positioned. The trapping members may also provide different functions at different stages of the process. For example, a trapping member positioned above the liquid level primarily for aeration may also (or instead) provide a bubble trapping role if air bubble generation increases and raises the air bubble level to the trapping member position.

[0052] In this embodiment, a venturi pump structure is used in conjunction with this air bubble trap to remove air bubbles from the liquid surface.

[0053] The Venturi pump structure may also be used in conjunction with an air bubble trap to aerate the liquid medium. Additionally, the Venturi pump structure may also be used in conjunction with an air bubble trap to provide a combination of aeration and removal of air bubbles from the liquid surface.

[0054] Venturi pumps rely on a pressure difference due to a relative constriction. This can be achieved, for example, between a primary tube for liquid flow and a secondary supply tube for air or another liquid. This creates a pumping effect from the supply tube to the primary tube. These devices can be configured in a variety of ways to achieve a pressure difference that results in a lower local pressure at the junction between the faster flowing primary liquid tube and the slower flowing supply tube.

[0055] In this embodiment, the venturi pump is an in-line flow-controlled venturi pump design based on controlling the pressurized air in the tank headspace and controlling the medium flow rate. A medium conduit 104 is positioned concentrically within the throat portion of the bubble trapping member 102 (where the narrowing of the member occurs from the wider mouth portion). Faster moving fluid can then be forced or driven in the conduit 104 in the direction 110 shown down the throat portion, creating a Venturi effect due to the relative narrowing created by the gap between the two concentric tubes and the narrowing of the trapping member up to this point.

[0056] The Venturi effect creates a pressure drop within the throat portion of the bubble capture member which draws or sucks in any air bubbles located at the mouth of the member in the direction indicated at 112. This provides a simple and effective means of capturing air bubbles.

[0057] In some embodiments, the constriction required for the pressure differential is formed by a concentric tube arrangement, with mixing occurring, at least in part, in / from the outer air tube rather than in the inner liquid tube.

[0058] The driving force for the liquid medium in the conduit 104 may be provided by a pumping device, in this case a pump external to the vessel. Other known similar means for driving a venturi may also be used.

[0059] The Venturi effect here also draws in headspace gas as shown in direction 114. Thus, with proper evaluation and optimization of the conditions within the vessel, this system can be used for bubble collection, for bubble collection and aeration of the medium, or just for aeration if required for a particular type of process, or if no bubbles are present (perhaps early or late in processing).

[0060] The system may be used solely for aeration of the medium on its own or when no air bubbles are present (e.g. early or late in processing). The system may be used solely for air bubble collection if necessary for a particular type of process or if other collection elements are present to provide other functions (e.g. aeration).

[0061] Headspace gas is drawn into the bubble trap in the direction indicated at 114 by the pressure drop in the throat portion of the bubble trap. This provides aeration for the process medium when the headspace gas is or contains air. The collection of headspace gas in the bubble trap can be an alternative to or in addition to the collection of air bubbles on the surface of the liquid medium described above.

[0062] This system can be used in combination with other similar and / or other known elements in fermenter designs to improve efficiency. For example, combining the bubble trapping effect with the aeration effect eliminates the need for separate components for these tasks. Combining the Venturi with other similar devices can provide additional bubble trapping and / or aeration at various or different points in the vessel. Combining this device with a mixing component can provide a combined aeration, bubble trapping and mixing device. In previously considered systems, this had to be provided using numerous different components, reducing efficiency.

[0063] In particular, providing a mixing device in series with a Venturi device as described above can provide efficiency benefits as well as improved processing results. In embodiments, the mixing component can be provided by another Venturi device, or by a device with a similar drag effect. This allows the pressure differential required to achieve the effect to be split between the two devices, minimizing the shear effects on microorganisms and bubble generation.

[0064] FIG. 1b shows an apparatus similar to that shown in FIG. 1a or to that shown in FIG. 1a. When the apparatus is combined with a mixing component, it can provide combined aeration and / or bubble trapping and mixing capabilities. In previously considered systems, this must be provided using a number of different components, reducing efficiency. Here, the trapping member 102 provides a Venturi effect driven by the input fluid in direction 110 to draw in gas and / or bubbles in direction 112. The output of the apparatus is then passed in direction 120 to a mixing device 130. For example, this can be via a conduit coupled to (or formed as part of) the lower portion of the trapping member 102, which is coupled to the mixing device 130. The input for the mixing device can combine the output of the trapping member 102 with other inputs, such as surrounding liquid medium in a vessel. In an embodiment, it may be sufficient to send the output of the trapping member generally in the direction of the mixing device, without the use of a dedicated conduit.

[0065] The mixing device 130 takes in input fluids from above in direction 122 and outputs mixed fluids downward in direction 124, thereby circulating these outputs, for example, towards the center or bottom of the bioreactor vessel. The input and output can be driven by the mixing device itself, for example, by a Venturi effect driven by the mixing device. In one embodiment, the Venturi effect is provided by the use of a mixing element, such as an impeller, that drives liquid downward through the mixing device, thereby drawing in the input fluid. In an embodiment, in addition to the input from the capture member 102 in direction 122, the surrounding liquid medium is drawn into the mixing device in direction 123. Thus, the mixing device can act not only on liquids, but also on mixed solutions of gas and liquid. In an embodiment, the mixing device can be located at a central or mid-level position in the vessel to provide a more consistent mix of gas into the liquid and avoid gradient effects.

[0066] 2 and 3, a specific embodiment of a bioreactor apparatus according to an embodiment of the present invention is shown. As can be seen, a venturi driven collection member 202 similar to that shown in FIG. 1 is provided within a vessel 201, with a constricted throat portion 204 providing that effect.

[0067] In this embodiment, the collection member 202 is positioned above the surface level of the liquid medium such that at least initially only headspace gas (here air) is drawn into the venturi, but the collection member is adapted to also collect air bubbles if they rise to this higher level during the process.

[0068] In an embodiment, an external mechanical pump 210 draws liquid medium through an outlet 227 at the bottom of the vessel and through an inlet at the top of the vessel to the collection member, creating a pressure differential where the inner tube (the conduit) terminates in the outer tube (the constricting collection member), creating a liquid flow in the direction 206 shown. The mouth of the collection member contains air and trapped surface bubbles, and the faster moving liquid in the conduit forms a venturi pump, thereby mixing the liquid medium with the air (and bubbles, if any).

[0069] In an embodiment, control of the aeration rate is achieved by simultaneously adjusting the air pressure and liquid flow rate: the flow rate is controlled by pump 210 and the air pressure is controlled by compressor 250, which provides headspace gas into the vessel.

[0070] In this embodiment, a network of two or more Venturi pumps is used to aerate the medium, recirculate biological bubbles, and mix the aerated medium, bubbles, and bulk tank medium to achieve improved microbial growth. The first medium / air and bubbles (if any / needed) mixing step is accomplished by the Venturi pumps 202 / 204. The second air / medium / bubble mixing creates dispersion throughout the tank, here accomplished by the Venturi pump 222. In this configuration, the Venturi pump 222 is an open system within the vessel. The components of the pump 300 can be seen in FIG. 3 along with the medium inputs 302 and 304. The impeller 306 is driven by the jet mixer 225. The cowling 228 / 310 around the impeller 306 creates a pressure differential creating a Venturi effect, acting to draw in the medium. This is in contrast to an aeration Venturi pump where the primary fluid motive force is upstream of the Venturi pump. Here, the fluid motive force is downstream of the Venturi pump so that the air bubbles / aerated liquid medium / tank liquid medium entering the Venturi pump collide with the impeller, thereby atomizing the air bubbles through mixing using the mechanical force of the blades, breaking up any remaining air bubbles, and dispersing the contents evenly throughout the tank in the direction of arrow 226.

[0071] In this embodiment, the venturi pump 222 functions as a mixing device.

[0072] It can be noted that the difference between this configuration and that of previously considered systems is that the driving force is provided (by the mixing impeller) below or after the constriction that enables the Venturi effect. The constrictions here are the conduits 302 and 304 that carry the input medium and air / bubbles.

[0073] Therefore, in this embodiment, a second (venturi) component provides mixing after the first venturi. In addition, this embodiment includes an additional venturi pump structure 223 with a dedicated bubble trapping member (unlike the bubble / gas / liquid trapping member 202) directly connected to the jet mixer cowling. This additional bubble trapping member is at a different level in the vessel. This is advantageous because bubble generation affects the surface level of the medium in the tank and the bubble level itself. Using two bubble trapping members located at different positions relative to the starting medium level allows for variations in foaming rate to be addressed.

[0074] In this embodiment, the first venturi pump structure and trapping member 202 may function primarily as the headspace gas trapping member 202, with the further venturi pump structure 223 functioning as a dedicated air bubble trapping member.

[0075] For example, one advantage of this structure is that the trapping member 202, due to its higher position, avoids clogging with air bubbles and can therefore provide aeration and mixing effect via the venturi more efficiently. The dedicated trapping member 223 provides the bubble trapping / suction function, which also assists in trapping air bubbles, as long as the air bubble height is not such that it reaches the first trapping member 202. Also, since the venturi effect for the dedicated bubble trapping member is, in embodiments, driven by only a single pump structure 222 / 223 (or is only connected to the mixing or venturi components by a single conduit or assembly), it can be advantageous that bubble trapping is more efficient and trapped air bubbles can be efficiently destroyed by a downstream mixing device.

[0076] In this embodiment, the dedicated bubble trapping member is positioned at the surface of the process medium such that the mouth of the trapping member is just above the liquid level and below the accumulating air bubbles (as in the position shown in FIG. 1a with reference to the bubble suction direction 112). In other embodiments, different arrangements of the trapping member may be used. For example, in one embodiment (e.g., for a low bubble generation process), a single trapping member adapted or arranged for air and bubble suction may be used. In other embodiments, multiple trapping members, each with the same or different functions, may be used at different positions in the vessel to enable the advantages described herein. Also, in further embodiments, other trapping members such as the dedicated bubble trapping member 223 may include a concentric Venturi effect structure similar to FIG. 1a, as well as being driven by a secondary mixing / Venturi device.

[0077] A further advantage of embodiments of the present invention is that aeration and mixing by the Venturi effect and / or combination of this with mixing by a second Venturi element, particularly using an impeller, can provide much smaller oxygen bubble sizes than previously contemplated systems, such as systems using air stones. Fine bubble sizes can improve aeration efficiency.

[0078] In addition, the mixing device assists in the flow of the aerated, pumped medium while simultaneously directly mixing the aerated, pumped medium with the main vessel medium while maintaining a high degree of uniform mixing of the aerated, pumped medium with, optionally, vessel air and air bubbles (if present) throughout the vessel. Also, in embodiments, the dual venturi design allows for the scaling of vessel sizes.

[0079] In this and other embodiments of the present invention, an improved aeration, sterilization and pressurization system is provided. Although an example is shown in Figure 4, this and similar systems can be applied to various types of bioreactors. Indeed, this system can also be used in other fields where a reliable supply of sterile gas / air is required in consistently maintained conditions.

[0080] Aeration systems for bioreactors generally require that both the incoming and outgoing air be sterile. In previously considered systems, this is achieved by filtration. Filtration systems require significant maintenance and servicing and are not suitable for humid environments (such as dye houses) that produce relatively large amounts of airborne microorganisms and spores. Traditional aeration systems also use materials such as air stones to generate microbubbles. Again, these devices require maintenance and some components require frequent replacement.

[0081] An embodiment of the invention can provide an external gas pump and heat sterilization system. Figures 2 and 4-7 show examples of embodiments of the invention, but these features can be applied to closed systems, especially pressurized systems and bioreactors. In general, the system provides a compressor or other gas supply / pressurization means, a heating system to sterilize the supplied gas, and a cooling system to cool the heated gas before it is supplied to the enclosure (here the bioreactor). The advantages of heat sterilization over conventional systems are that filtration (and thus filter clogging and disposal) is not required and many more different types of microorganisms and contaminants can be removed compared to, for example, UV treatment.

[0082] In the example shown in FIG. 2, a compressor 250 provides a supply of gas (usually air) to the system under a maintained pressure (variable if necessary). When the headspace gas supplied is air, it can be extracted from the surrounding environment. In this embodiment, the pumped air is heated to 250° C. by a sterilization unit 252 to inactivate live microorganisms, spores or viruses from the ambient air source, and then rapidly cooled to 30° C. before entering the tank headspace. The tank headspace maintains a controlled pressure, as the air leaving the tank is pumped back to another heat sterilization stage 254 before being returned to the environment. Thus, the air in the tank headspace can be maintained at a suitable temperature and pressure for aeration of the medium via a Venturi pump network. Importantly, this can be achieved regardless of the ambient or environmental conditions, no matter where the bioreactor is located. The headspace gas can be provided at the same temperature and consistent pressure in all circumstances.

[0083] In the example shown in Figures 4-7, the system includes a compressor 402, a sterilization box 404, a coil section 406, and a cooling device 408. The compressor in many examples is an air compressor that provides air from the environment, which must then be sterilized and provided at sufficient pressure to a pressurized enclosure, such as a certain type of bioreactor. The sterilization box 404, shown in detail in Figure 5, is essentially an enclosure 502 that contains a series of electrical resistors 504 to heat the incoming gas. In this example, the gas, air, is heated to 250°C.

[0084] The sterilization box 404 functions as a heating chamber. In an embodiment, the heating chamber (i.e., the sterilization box 404) heats the incoming gases to between 120° C. and 300° C. depending on the microbial environment and the level of sterilization required.

[0085] Gas is delivered from the compressor by a conduit to the sterilization box and a similar outlet conduit delivers heated gas to a coil section 406 (shown in FIG. 6). This component is essentially a coiled, helical or serpentine shaped conduit which then feeds a cooling device 408.

[0086] Sterilization of air by heating presents challenges. Biological contaminants in the incoming (non-sterile) air may be protected from heating by the air boundary around the contaminant, especially if the airflow is laminar in nature. This can reduce the efficiency of heat transfer and the rate of sterilization (by heat transfer inactivation of biological contaminants). Although there are previously considered systems for heat sterilization of air, none meet the requirements for bioreactors / fermenters or other situations where filtration and UV alone cannot be successful. In these systems, the airflow and temperature required for biological inactivation are not compatible with the downstream use of the air to be sterilized, as the temperature and airflow design do not inactivate biological contaminants at the required rate / level. Bioreactors / fermenters typically provide an ideal environment for microbial growth and are therefore highly susceptible to contamination by biological contaminants. Advantageously, the apparatus and systems of the present embodiments exhibit extremely low contamination rates, especially when gases (including, for example, air) are sterilized according to the present embodiments.

[0087] In an embodiment of the invention, the temperature of the air in the heating chamber 404 may not be uniform since the incoming air to be heated is initially at room temperature and may vary in a spatially determined manner due to, for example, laminar flow. Therefore, the coil section 406 is designed to create mixing / turbulence and keep the heated air at the inactivation temperature because the configuration of the coil unit allows it to equilibrate to the temperature of the heating chamber. The coil section contracts and spatially restricts the incoming heated air from the heating chamber. This (in an embodiment, in combination with a compressor) creates a forced or dynamic air environment, resulting in a more uniform heat distribution and turbulence, thereby increasing the heat exposure time and / or decreasing the time required to inactivate airborne biological contaminants, resulting in more efficient heat transfer inactivation. The turbulence created significantly increases the probability of physical contact between the biological contaminants and the heated components. Direct contact typically results in near instantaneous inactivation of biological contaminants. Turbulence in the gas flow is also desirable because it tends to mix the gas and promote a more uniform heat distribution in the gas, thereby reducing or avoiding relative hot or cold spots in the gas that might otherwise not be properly sterilized.

[0088] Thus, rather than simply immediately cooling it to provide heated gas to the enclosure / bioreactor, this coiled section can maintain an elevated temperature for the gas for an extended period (longer period) after the initial heating stage (without necessarily heating it) due to the length of time required for the gas to travel the entire length of the coil.

[0089] The coil 604 is provided within the housing 602 in as compact a form as possible for convenience and ease of temperature maintenance. Inlet gas travels along the coiled conduit in the direction indicated at 606 to the outlet where it is cooled.

[0090] The inventors have found that the provision of this additional portion, which allows the gas heat to be maintained for much longer, can provide even greater sterilization capacity, especially compared to conventional systems. In addition, the system can provide a very consistent gas / air supply at high flow rates, for example for the illustrated system at around 200 liters per minute, compared to previously considered systems. This is achieved in part thanks to the omission of any type of filtration from the system, which would slow down the flow rate. No filters are required to remove microorganisms or other contaminants, due to the comprehensive sterilization effect of the system of the present embodiment. A significant component of the flow capacity is the provision of heating (or temperature maintenance) over a much longer travel distance than previously envisioned, thereby providing a long sterilization period despite the high flow rate.

[0091] This high flow rate is an advantage in many environments and formats, but especially in bioreactors according to embodiments of the invention. In some embodiments, the goal may be to provide an airflow:liquid volume ratio of about 1:1, for example, so that the number of liters (per minute) provided to the enclosure is comparable to the volume of liquid medium in the enclosure. This is advantageous, for example, in use cases where it is important to maintain bacteria in the bioreactor medium in a high oxygen environment, for example during aerobic fermentation. The high flow rate of embodiments of the invention means that the partial pressure of dissolved oxygen (pDO) in the bioreactor can be maintained higher than 50% more easily and efficiently than in previously considered systems. In embodiments, the system uses pressure difference principles (e.g., pressure of about 2 bar in the tank headspace) to ensure a high, homogenized oxygen transfer between the gas and liquid phases.

[0092] In an embodiment, for example if a higher flow rate is required or possible, the coil portion 406 may also include a heating device. The coil is typically made of stainless steel.

[0093] A cooling device 408 is shown in FIG. 7. The device includes a fan 702 mounted in the housing with vaned channels 704 for passing gas. Gas from the heating section is inlet into the device and travels in a direction indicated at 706 from the bottom of a first vaned channel section, travelling in an alternating or zigzag path to increase residence time in the cooling device, then descends through a corresponding section on the opposite side of the device. This device is sufficient to cool the gas temperature down to 250° C.-30° C. before being injected into an enclosure or pressurized device. Similar known cooling devices can also be used to provide a similar cooling effect.

[0094] In an embodiment of the invention, the cooling device includes a fan-driven cooling unit that passes heated air through a heat exchanger connected to the vessel. In an embodiment, the fan-driven cooling unit includes a fan 702. Thus, in an embodiment, the cooling device and the vessel (e.g., a bioreactor) can both act as a heat sink.

[0095] The outlet sterilization chamber 254 shown in Figure 2, which is applicable to other embodiments, can be provided with the same or similar components as those shown in Figures 4-7, but of course without the need for a compressor. Where appropriate, these components can be simplified, as it may not be necessary to provide the same levels of sterilization and / or cooling.

[0096] In embodiments of the present invention, the sterilization system is scalable in that each component can be modified in size and capacity, and all stages can be designed to work in unison to provide the required flow rate of sterile air.

[0097] Additionally, in embodiments, the systems shown in Figures 4-7 may be provided with temperature sensors and / or monitoring systems to enable them to be used as a component for heating the bioreactor contents or as the primary heating modality for heating the bioreactor contents.

[0098] The devices, systems and methods of the present invention are not limited to any particular type of microorganism: the present invention (and the advantages provided thereby) are applicable to any type of microorganism that can be cultured in liquid media, such as bacteria (such as E. coli), yeast (such as Pichia coli or Saccharomyces cerevisiae), or mammalian cells (such as Chinese hamster ovary cells, NSO mouse myeloma cells, baby hamster kidney cells, green monkey kidney cells, or human fetal kidney cells).

[0099] As described herein, the present invention achieves better aeration and mixing than previously contemplated systems. Because of this better aeration and mixing, the present invention is particularly suitable for use with microorganisms that are prone to aggregation (e.g., prone to autoaggregation). A non-limiting example of an autoaggregating bacterium includes E. coli.

[0100] In some embodiments, the microorganism is a recombinant microorganism. In some embodiments, the recombinant microorganism expresses a recombinant product, e.g., a recombinant protein. In some embodiments, the recombinant microorganism is engineered to modulate production of a product that is naturally produced by that type of microorganism. In some embodiments, the microorganism is mutated compared to its native form. In some embodiments, the mutated microorganism produces a different level of a product compared to its native form. The product may include, but is not limited to, an industrial product (e.g., for use in the textile industry), a therapeutic product, or a primary metabolite (e.g., ethanol).

[0101] In other embodiments of the invention, the systems shown in these figures and described in any of the above embodiments may advantageously include sensors within the vessel and / or within components of the system to aid in system management. For example, sensors within the vessel may monitor temperature, pressure, pH, etc.

[0102] Those skilled in the art will appreciate that the invention has been described by way of example only and that various alternatives can be adopted without departing from the scope of the invention as defined by the appended claims.

[0103] In particular, the above description refers to the air bubble trapping member (102, 202). However, one skilled in the art will appreciate that in a particular application, or at a particular position relative to the liquid medium level, the air bubble trapping member may trap only gas, only liquid medium, or any combination of gas, liquid medium, and air bubbles. For example, in the early stages of processing, when no air bubbles have yet been generated, the air bubble trapping member may trap only gas and / or liquid medium. Similarly, when the air bubble trapping member is positioned above the level of the liquid medium during use, the air bubble trapping member may trap only gas until enough air bubbles have formed to raise the air bubble level above the level of the mouth portion of the air bubble trapping member.

[0104] The above description also refers to a coil section (406). However, those skilled in the art will appreciate that the coil section functions as a holding unit for the gas and may therefore be replaced by alternative structures that similarly function as a gas holding unit. For example, the holding unit may include a series of connected chambers or winding or spiral pipe sections to direct the gas flow from the sterilization box to the cooling device while maintaining the gas at an elevated temperature longer than if the gas were delivered directly from the sterilization box to the cooling device.

Claims

1. a container for containing a liquid medium and a headspace gas; Venturi pump assembly and the venturi pump assembly comprising: a medium outlet conduit; a medium inlet conduit; a pump device configured to draw medium from the container through the medium outlet conduit and pass it through the medium inlet conduit; an air bubble collecting member including a mouth portion and a narrowed throat portion, the mouth portion being disposed at the surface of the liquid culture medium in the container; Including, the culture medium inlet conduit is arranged to pass pumped culture medium through the throat portion of the bubble trapping member to create a reduced pressure region therein for drawing surface bubbles into the mouth portion of the bubble trapping member.

2. 2. The bioreactor apparatus of claim 1, wherein the medium inlet conduit is positioned to enter the mouth portion of the bubble trapping member and pass the pumped medium through the throat portion.

3. The bioreactor apparatus of claim 1 , wherein the pump device is located outside the vessel.

4. 2. The bioreactor apparatus of claim 1, wherein the mouth portion is adapted to draw headspace gas into the mouth portion of the bubble trapping member in the direction of pumped culture medium passing through the throat portion of the bubble trapping member while creating a reduced pressure region therein.

5. The bioreactor apparatus of claim 1 , further comprising a mixing device for mixing any one of the air bubbles from the air bubble collecting member, the headspace gas, and the liquid medium.

6. The bioreactor apparatus of claim 5 , wherein the mixing device is located downstream of the bubble trapping member.

7. 7. The bioreactor apparatus of claim 6, wherein the mixing device is fed from the bubble trapping member by at least a first intermediate medium conduit.

8. 7. The bioreactor apparatus of claim 6, wherein the mixing device comprises an impeller, the impeller adapted to draw any of the air bubbles, headspace gas and / or liquid medium into the mixing device and / or to atomize a mixture of any of the air bubbles, headspace gas and / or liquid medium.

9. 6. The bioreactor apparatus of claim 5, wherein the mixing device is adapted to create a region of reduced pressure to draw vessel contents into the mixing device.

10. 10. The bioreactor apparatus of claim 1, further comprising an additional air bubble trapping member, said additional air bubble trapping member being spaced apart from said air bubble trapping member.

11. 11. The bioreactor apparatus of claim 10, wherein the bubble trapping member and the further bubble trapping member are positioned at different heights within the vessel.

12. 11. The bioreactor apparatus of claim 10, wherein the further air bubble trapping member is positioned lower within the vessel so that, during use, as the height of air bubbles in the vessel increases, the air bubbles reach the further air bubble trapping member before the air bubble trapping member.

13. a container for containing a liquid medium; Venturi pump assembly and the venturi pump assembly comprising: a medium outlet conduit; a medium inlet conduit; a pump device configured to draw medium from the container through the medium outlet conduit and pass it through the medium inlet conduit; a collection member including a mouth portion and a constricted throat portion; a mixing device disposed downstream of the collection member; Including, the medium inlet conduit is arranged to pass pumped medium through the throat portion of the collection member to create a reduced pressure region therein for drawing container contents into the mouth portion of the collection member; The bioreactor apparatus, wherein the mixing device is adapted to mix the vessel contents captured by the capture member.

14. 14. The bioreactor apparatus of claim 13, wherein the mixing device is fed from the capture member by at least a first intermediate medium conduit.

15. 14. The bioreactor apparatus of claim 13, wherein the mixing device comprises an impeller, the impeller adapted to draw any of the air bubbles, headspace gas and / or liquid medium into the mixing device and / or to atomize a mixture of any of the air bubbles, headspace gas and / or liquid medium.

16. 15. The bioreactor apparatus of claim 14, wherein the pumping device comprises a first drive means and the mixing device comprises a second drive means.

17. The bioreactor apparatus according to any one of claims 1 to 16, further comprising a dedicated air bubble trapping member, the dedicated air bubble trapping member comprising a mouth portion disposed at a liquid medium surface position opposite to the surface position of the air bubble trapping member.

18. 18. The bioreactor apparatus of claim 17 when dependent on claim 11, wherein a dedicated bubble collection conduit is coupled to the dedicated bubble collection element and impeller housing, the impeller further adapted to create a reduced pressure region for drawing surface bubbles into the mouth portion of the dedicated bubble collection element.

19. 18. The bioreactor apparatus of claim 17, wherein the specialized bubble trapping member includes a narrowed throat portion.

20. 14. The bioreactor apparatus of claim 13, wherein the pumping device is located outside the vessel.

21. a container for containing a liquid medium and a headspace gas; Venturi pump assembly and the venturi pump assembly comprising: a bubble trapping member having a mouth portion and a narrowed throat portion; a culture medium conduit disposed within the bubble trapping member and concentric with the narrowed throat portion; Pump device and Including, the pump device is arranged to pump culture medium from the container through the culture medium conduit, thereby creating a reduced pressure region for drawing surface bubbles and / or headspace gas into the mouth portion of the bubble trapping member.

22. an environmental gas compressor; a first sterilization unit operable to receive gas from the compressor, heat the gas to a predetermined sterilization temperature, cool the gas to a predetermined enclosure temperature, and supply sterilized gas to a sealed chamber; 1. A system for maintaining environmental conditions within a sealed chamber, comprising:

23. 23. The system of claim 22, wherein the sealed chamber is pressurized.

24. 23. The system of claim 22, wherein the enclosed chamber is a bioreactor.

25. 23. The system of claim 22, wherein the first sterilization unit includes an intermediate chamber operable to receive gas heated to the predetermined sterilization temperature and to output gas that is cooled to the predetermined enclosure temperature.

26. 26. The system of claim 25, wherein the intermediate chamber includes a coiled conduit, the conduit including an inlet end for receiving heated gas and an outlet end for producing cooled gas.

27. 23. The system of claim 22, including a second sterilization unit operable to receive gas from the sealed chamber and heat the gas.

28. 28. The system of claim 27, wherein the second sterilization unit is operable to heat the gas and then cool the gas to a predetermined ambient temperature.

29. A bioreactor device according to any one of claims 1, 13 and 21; The system of claim 22.

1. A bioreactor system comprising:

30. 23. Use of a bioreactor device according to any one of claims 1, 13, 21 or a system according to claim 22 in a fermentation process.

31. a container for containing a liquid medium; a venturi assembly including a medium outlet conduit, a medium inlet conduit, a pump device, an inlet member including a mouth portion and a throat portion, and a mixing device; providing a using the pump device to draw medium from the container through the medium outlet conduit and pass it through the medium inlet conduit; passing pumped culture medium through the throat portion of the inlet member to create a reduced pressure region therein for drawing container contents into the mouth portion of the inlet member; and mixing the container contents collected by the inlet member using the mixing device.

1. A method for bioreactor processing comprising:

32. providing an environmental gas compressor and a sterilization unit; receiving gas from the compressor in a sterilization unit; heating the gas to a predetermined temperature; and supplying sterilized gas to said container; 32. The method for bioreactor treatment of claim 31, comprising:

33. providing an elongated heating portion; receiving an input gas; throttling the input gas using the elongated heating portion; heating the gas to a predetermined sterilization temperature using the elongated heating portion; and supplying sterilized gas to said container; 32. The method for bioreactor treatment of claim 31, comprising:

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