Bioreactor and method for gassing a biological system

Abstract

The invention relates to a bioreactor (100, 502) for gassing a biological system, comprising a cover system (104), a fluid container (102, 506) and a gassing and stirring unit (106, 504), wherein the cover system (104) and the fluid container (102, 506) together form a reactor chamber (108, 510) and the gassing and stirring unit (106, 504) is located in the reactor chamber (108, 510). The bioreactor is characterised in that: the cover system (104) has a fluid inlet (122) and a hollow drive shaft (126, 514) having an inner channel (128), wherein the fluid inlet (122) and the inner channel (128) of the hollow drive shaft (126, 514) are flow-permeably interconnected; the gassing and stirring unit (106, 504) has a connecting region (144) having a fluid inlet (146), has at least one membrane element (148, 516) and has a fluid outlet (150), wherein the fluid inlet (146), the membrane element (148, 516) and the fluid outlet (150) are flow-permeably interconnected; and the fluid inlet (122) of the cover system (104), the inner channel (128) of the hollow drive shaft (126, 514), the fluid inlet (146) of the gassing and stirring unit (106, 504), the at least one membrane element (148, 516) and the fluid outlet (150) of the gassing and stirring unit (106, 504) form a fluid section (154) and the fluid outlet (150) of the gassing and stirring unit (106, 504) opens into the reactor chamber (108, 510).

Description

[0001] GO / sw 241019DE

[0002] December 17, 2025

[0003] Bioreactor and methods for gassing a biological system

[0004] The present invention relates to a bioreactor for aerating a biological system, comprising a cover system, a fluid reservoir, and an aeration and stirring unit, wherein, in an assembled state of the bioreactor, the cover system and the fluid reservoir together form a reactor chamber, and the aeration and stirring unit is arranged in the reactor chamber. The present invention further relates to a method for aerating a biological system.

[0005] Biological systems, such as those involving bacteria, archaea, fungi, plants, or enzyme reactions, particularly those involving human and animal cells, are especially sensitive to shear forces. This is particularly true for biological systems containing stem and / or immune cells, or assemblies such as organoids. Despite this shear sensitivity, or susceptibility to shear forces in fluid flows, the transfer of substances between fluids is frequently required, for example, in microbiological investigations or cell cultures. Examples of such transfers include the transfer of CO2 from the air into water or the transfer of a dissolved, nonpolar product from a preceding chemical reaction into an extraction fluid.Mass transfer is generally caused or at least facilitated by bringing the substances involved in the transfer into contact with each other, for example by mixing, blending, dispersing, or similar processes. Therefore, it is regularly desirable to both aerate and stir the fluids in question.

[0006] It is known from the prior art to introduce a liquid or culture medium as the first fluid in a bioreactor and to introduce a gas as the second fluid using an aeration and stirring unit immersed in the liquid, as is known, for example, from publication WO 2021 / 152128 Al. The aeration and stirring unit can be designed as a movable unit with at least one membrane element, wherein the at least one membrane element is provided for diffusive or convective transfer of the gas into the liquid. Thus, a gas from outside the bioreactor can be introduced directly into the aeration and stirring unit, at least partially transferred into the liquid through the membrane element, and the residual gas can be discharged from the bioreactor through a gas outlet of the aeration and stirring unit.

[0007] In known systems, gaseous water from the reactor fluid also passes through the membrane and is continuously flushed out of the reactor. Over time, this reduces the liquid volume in the reactor and increases the concentration of salts, etc., in the reactor medium, which can lead to osmotic stress for the organisms in the reactor. For this reason, water is usually added periodically, or the gas flow is returned to the reactor. A condenser can be provided at the gas outlet of the reactor to condense the moisture and return it to the reactor as a liquid. A disadvantage of this method is that gas transfers in the so-called "headspace," located in the bioreactor between the medium level and the lid, remain uncontrolled.

[0008] If the reactor headspace is not purged, gases (e.g. CO2) can accumulate there and diffuse back into the medium via the medium level, negatively affecting the process control.

[0009] Against this background, the present invention aims to provide improved means for aeration and stirring of biological systems.

[0010] The aforementioned task is accomplished with a bioreactor for the aeration of a biological system, with a cover system, with a fluid container, and with

[0011] GO / sw 241019DE

[0012] December 17, 2025, of a gassing and stirring unit, wherein, in an assembled state of the bioreactor, the cover system and the fluid container together form a reactor chamber and the gassing and stirring unit is arranged in the reactor chamber, in that the cover system has a fluid inlet and a drive hollow shaft with an inner channel, wherein the fluid inlet and the inner channel of the drive hollow shaft are flow-permeable, that the gassing and stirring unit has a connection area with a fluid inlet, at least one membrane element and a fluid outlet, wherein the fluid inlet, the membrane element and the fluid outlet are flow-permeable, and that, in an assembled state of the bioreactor, the fluid inlet of the cover system, the inner channel of the drive hollow shaft, the fluid inlet of the gassing and stirring unit,that at least one membrane element and the fluid outlet of the aeration and stirring unit form a fluid path and the fluid outlet of the aeration and stirring unit opens into the reactor chamber.

[0013] The aforementioned problem is further solved by a method for gassing a biological system, in which a bioreactor with a reactor chamber and with a gassing and stirring unit arranged in the reactor chamber, in particular a bioreactor according to the disclosure, is provided, in which the reactor chamber is partially filled with a first fluid, preferably as a liquid, so that a first volume fraction of the reactor chamber is occupied by the first fluid, in which a second fluid, preferably gaseous, is introduced into the gassing and stirring unit for a first fluid transfer and is introduced into the first fluid via the gassing and stirring unit essentially diffusively.in which the second fluid from the gassing and stirring unit is guided into a second volume fraction of the reactor space arranged in the direction of the gravitational force above the first volume fraction and is brought into contact with the first fluid at the free surface of the first fluid in the reactor space for a second fluid transfer.

[0014] GO / sw 241019DE

[0015] December 17, 2025. The disclosed bioreactor and process propose dual gassing, achieved firstly through at least one membrane element of the gassing and stirring unit immersed in the medium to be gassed, and secondly at the free surface of the medium. Simultaneously, the medium can be stirred by the gassing and stirring unit, thereby optimizing the distribution of the gas in the liquid or medium and controlling the formation and size of gas bubbles. Furthermore, the disclosed solution allows moisture to be retained in liquid form within the reactor, while gases can be collected and discharged. In addition, the disclosed solution offers the option of a complete reactor exhaust gas analysis, which is rather difficult with the aforementioned prior art gassing and stirring unit.

[0016] The fluid vessel preferably has a wall with a bottom section and a wall section. The bottom section and the wall section can be formed as a single piece. Alternatively, the bottom section and the wall section can be formed as separate components, which can then be connected to each other in a flow-tight manner. Optionally, the bottom section and the wall section can be detachably connected to allow for the replacement of the bottom section as needed, depending on the application of the bioreactor.

[0017] The cover system is preferably designed to be flow-tight, for example by means of a sealing element, connected to the wall of the fluid container. In an assembled state of the bioreactor, the fluid container and the cover system are connected to each other and together form a cavity for receiving at least one fluid. This cavity corresponds to a reactor chamber within the meaning of the present disclosure.

[0018] The cover system has a fluid inlet and a drive hollow shaft with an inner channel, wherein the fluid inlet and the inner channel of the drive hollow shaft are connected in a flow-permeable manner. For this purpose, the

[0019] GO / sw 241019DE

[0020] December 17, 2025 Cover element shall have a cavity that at least partially surrounds the drive hollow shaft and is permeable to the fluid inlet, the drive hollow shaft shall have an opening and the cavity of the cover element shall be permeable to the opening of the drive hollow shaft.

[0021] Preferably, the drive hollow shaft is designed to drive the gassing and stirring unit for a rotational movement into the reactor chamber in an assembled state of the bioreactor.

[0022] The aeration and stirring unit is preferably designed for both fluid transfer, for example, gas transfer, and stirring of a fluid or medium contained in the fluid vessel. The aeration and stirring unit has a connection section with a fluid inlet. This connection section is preferably connectable to the drive hollow shaft of the cover element in such a way that, in an assembled state of the bioreactor, a fluid, in particular a gas, can be introduced through the drive hollow shaft and guided via the fluid inlet to the membrane element of the aeration and stirring unit, and a driving force can be transmitted from the drive hollow shaft to the aeration and stirring unit.

[0023] The aeration and stirring unit comprises at least one membrane element. Preferably, the aeration and stirring unit is designed to maximize fluid transfer between a fluid supplied to the unit through its fluid inlet and a fluid in the reactor chamber. For this purpose, the aeration and stirring unit can be designed for rotational movement within the reactor chamber, with the at least one membrane element designed for molecular diffusive transfer and arranged, for example, in a radial spiral or as circular segments with an axial, turbine-blade-like arrangement.

[0024] GO / sw 241019DE

[0025] December 17, 2025. A molecular-diffusive transfer of a first fluid into a second fluid differs from convective mass transfer in that the molecular-diffusive transfer occurs without direct contact, i.e., without the two fluids coming into direct contact. In convective mass transfer, the first fluid is brought into direct contact with the second fluid, for example, by the first fluid flowing through a porous interface into the second fluid. Such convective mass transfer is known, for example, from the application of so-called spargers. Convective mass transfer typically results in the formation of bubbles, which are generally detrimental in biological systems.In contrast, in a molecular-diffusive transfer, as in this case via the membrane element of the aeration and stirring unit, molecules of the first fluid are diffusively guided through the membrane element, i.e., indirectly via the membrane element, to the second fluid. Thus, the molecular-diffusive transfer occurs essentially without bubbles, resulting in a particularly gentle aeration of biological systems in particular.

[0026] The gassing and stirring unit can preferably be used to bring about both molecular diffusive transfer and convective mass transfer. The molecular introduction of a gas into the gassing and stirring unit into a fluid in the reactor chamber occurs diffusively, on the one hand directly via the membrane surface, and on the other hand indirectly via the surface of the gas bubbles formed during convective gas introduction.

[0027] The aeration and stirring unit can be driven at a stirring rate. A stirring rate, as defined in this disclosure, can be expressed as the number of movement cycles per unit of time or as units derived therefrom. Examples include: number of rotations per minute, number of oscillations per minute, although this list is not exhaustive. The stirring rate can be used to determine both the input of kinetic energy (energy dissipation) and the homogenization of the reactor contents.

[0028] GO / sw 241019DE

[0029] December 17, 2025 Gas transfer has a significant impact on a cell culture taken up by the bioreactor.

[0030] In addition, the aeration and stirring unit can be supplied according to an aeration rate. An aeration rate, as defined in this disclosure, can be understood as the volumetric flow rate of a volume of gas that is fed into the aeration and stirring unit of the bioreactor, or that exits the gas pump of the control system and is, if applicable, supplied to the bioreactor. The aeration rate can be expressed as gas volume per unit of time or in units derived therefrom. The influence of the aeration rate on the diffusive transfer of the gas into the medium of the bioreactor can be asymptotic or stabilize above a certain threshold.

[0031] Furthermore, gas introduction can be achieved using the aeration and stirring unit. This gas introduction corresponds to the diffusive introduction of a gas into a medium contained within the reactor chamber, for example, a liquid. If the medium contains a cell culture, the gas introduction has a significant impact on the cell culture. The gas introduction can be understood as a volumetric transfer coefficient. It can be expressed as a gas volume per volume of culture medium per unit of time, or in units derived from this. The gas introduction can result from fluid transfer via the at least one membrane element of the aeration and stirring unit, or alternatively or additionally from so-called "headspace aeration."

[0032] In this context, "headspace aeration" refers in particular to fluid transfer at the surface of a culture medium contained in the bioreactor, whereby a gas that at least partially penetrates the culture medium in the space between the lid of the bioreactor and the surface of the culture medium contained in the bioreactor diffuses, mixes, or is otherwise transferred. Such headspace aeration can, in principle, be carried out with or without the use of an aeration and stirring unit. The bioreactor disclosed is designed for a

[0033] GO / sw 241019DE

[0034] December 17, 2025: Gassing through the gassing and stirring unit and additionally for headspace gassing.

[0035] The bioreactor, in particular at least one element from the list (fluid container, cover system, aeration and stirring unit), can be designed for single use or a so-called "single-use" process. This eliminates the need for complex sterilization or cleaning procedures at the user's site. Furthermore, cost-effective materials can be used in the bioreactor's construction, as durability requirements are low.

[0036] The following describes various embodiments of the bioreactor and the process, each embodiment being independent of the other. Furthermore, the individual embodiments can be combined with one another as desired.

[0037] In one embodiment of the bioreactor, the connection area of ​​the gassing and stirring unit is designed for connection with the drive hollow shaft, the connection being designed both for transmitting a drive force and for transmitting a fluid to the gassing and stirring unit.

[0038] In this way, in addition to the hollow drive shaft, further gas connections can be omitted to supply the gas supply and stirring unit. Furthermore, the hollow drive shaft allows gas to be supplied even during rotation of the gas supply and stirring unit, i.e., independently of its rotation.

[0039] The connection area is preferably connectable to the drive hollow shaft of the cover element in such a way that, in an assembled state of the bioreactor, a fluid, in particular a gas, is introduced through the drive hollow shaft and via the fluid inlet to the membrane element of the aeration and

[0040] GO / sw 241019DE

[0041] December 17, 2025, a stirring unit can be guided, and on the other hand, a driving force can be transferred from the drive hollow shaft to the gassing and stirring unit.

[0042] In one embodiment of the bioreactor, it is provided that the cover system has at least one fluid outlet, and that, in an assembled state of the bioreactor, the reactor chamber and the at least one fluid outlet of the cover system further form the fluid path downstream to the fluid outlet of the aeration and stirring unit.

[0043] In this way, a fluid, especially a gas, can be released from the bioreactor or reactor chamber through the cover system. Thus, the headspace in the reactor chamber and the at least one fluid outlet of the cover system are located downstream of the aeration and stirring unit in the fluid path formed by the fluid inlet of the cover system, the drive hollow shaft, and the aeration and stirring unit.

[0044] Providing the fluid outlet on the cover system allows for optimized spatial use of the reactor space and standardized manufacturing of the fluid container or the wall area of ​​the fluid container.

[0045] The at least one fluid outlet of the cover system can be equipped with a valve or similar device to control the pressure in the headspace or reactor chamber. Increased pressure in the headspace allows more gas to dissolve into the liquid contained in the reactor chamber.

[0046] Alternatively or additionally, the fluid outlet can be provided on the wall of the fluid container, thus achieving the same effect as a fluid outlet from the headspace of the bioreactor. In this case, the reactor chamber and the at least one fluid outlet of the fluid container then form the fluid path leading to the fluid outlet of the aeration and stirring unit. When a fluid outlet is provided both on the cover system and on the wall of the

[0047] GO / sw 241019DE

[0048] From December 17, 2025, fluids with different properties, such as density, can be released from the reactor chamber, possibly separately from each other, via the fluid container.

[0049] In one embodiment of the bioreactor, the cover system comprises a first cover element and a second cover element, the first cover element and the second cover element are connected to each other via a flow-tight connection and together form a cavity, the drive hollow shaft has a wall forming the inner channel with at least one penetrating opening, and the fluid inlet of the cover system and the inner channel of the drive hollow shaft are connected in a flow-permeable manner via the cavity and via the at least one penetrating opening in the wall of the drive hollow shaft.

[0050] This reduces the number of components required for transmitting driving force on the one hand and fluid flow on the other. This allows for simplified manufacturing and scaling of the bioreactor both upwards, for larger volumes (so-called "up-scaling"), and downwards, for smaller volumes (so-called "down-scaling").

[0051] Preferably, the cavity formed by the first and second cover elements surrounds the drive hollow shaft at least in the section of the wall that has the penetrating opening. In this way, a fluid can be transferred to the interior of the drive hollow shaft independently of a rotational movement of the drive hollow shaft, for example, during power transmission from the drive hollow shaft to the aeration and stirring unit.

[0052] Furthermore, it can be provided that the first cover element has a first penetrating opening for receiving a first area of ​​the drive hollow shaft, that a first bearing element and a first sealing element are received on the first cover element in such a way that the first cover element and

[0053] GO / sw 241019DE

[0054] December 17, 2025, the first area of ​​the drive hollow shaft is rotatably and fluid-tightly connected to each other, that the second cover element has a second penetrating opening for receiving a second area of ​​the drive hollow shaft, that a second bearing element and a second sealing element are received on the second cover element in such a way that the second cover element and the second area of ​​the drive hollow shaft are rotatably and fluid-tightly connected to each other, and that the penetrating opening of the drive hollow shaft is arranged between the first area and the second area.

[0055] Thus, the cavity is sealed against an atmosphere outside the reactor space and the drive hollow shaft can undergo a rotational movement.

[0056] In one embodiment of the bioreactor, the drive hollow shaft has a first distal end for connection with a drive element and a second distal end for connection with the gassing and stirring unit, wherein the first distal end is designed for connection with a mechanical drive element or for connection with a magnetic drive element, and wherein the inner channel of the drive hollow shaft is closed in a flow-impermeable manner at the first distal end.

[0057] Depending on the application of the bioreactor, either a mechanical or a magnetic drive may be advantageous. For example, if magnetic particles are used in the reactor chamber to separate components of a culture, a magnetic drive could negatively affect the separation process, and it is therefore advisable to avoid using a magnetic drive to prevent interference with the treatment.

[0058] A closure of the inner channel at the first distal end of the drive may be provided if a gas is to be introduced through a fluid inlet in the cover system, in particular in a cover element of the cover system.

[0059] GO / sw 241019DE

[0060] December 17, 2025. Alternatively or additionally, the interior of the drive hollow shaft can be left open at the first distal end, for example, to introduce a fluid directly into the interior of the drive hollow shaft. In this case, the first distal end of the drive hollow shaft can be open and correspond to the fluid inlet of the cover system as disclosed. Such a design can be used, for example, for a dual fluid flow system, where a first fluid is to be supplied to the aeration and stirring unit and, in parallel, a second fluid is to be discharged from the aeration and stirring unit.

[0061] In one embodiment of the bioreactor, the drive hollow shaft has a first distal end for connection with a magnetic drive element and a second distal end for connection with the gassing and stirring unit, wherein the inner channel of the drive hollow shaft is open to allow flow at the first distal end.

[0062] This allows for a simplified design of the bioreactor, particularly the cover system. The open distal end of the drive shaft allows gas to be introduced directly into the interior of the drive shaft, independent of any rotational movement of the shaft.

[0063] The first distal end of the hollow drive shaft, or the inner channel of the hollow drive shaft, can open into the cavity of the cover system. This simplifies the sealing of the cavity. In particular, this minimizes the number of sealing elements and bearing elements.

[0064] Alternatively, the drive hollow shaft can pass through the cover system and the first distal end of the drive hollow shaft or the inner channel of the drive hollow shaft can form the fluid inlet of the cover system.

[0065] GO / sw 241019DE

[0066] December 17, 2025 In one embodiment of the bioreactor, the fluid container is provided to have a bottom section with a substantially flat base profile. This allows the bottom section to be adapted to a flat floor material or support.

[0067] In one embodiment of the bioreactor, the fluid container is provided to have a bottom area with a medium collection area.

[0068] The medium collection area facilitates the emptying of the bioreactor or its fluid container. Furthermore, it helps to collect components separated during cultivation by the rotation of the aeration and stirring unit.

[0069] The medium collection area can be formed as a local low point in the direction of the gravitational force. This allows collection to be achieved through centripetal acceleration and / or due to the gravitational force.

[0070] Alternatively or additionally, the aeration and stirring unit can be rotatable relative to an axis of rotation, the aeration and stirring unit can be essentially cylindrical with an outer diameter and a principal axis of extension, the principal axis of extension being parallel to the axis of rotation, and, viewed in a cross-sectional view perpendicular to the axis of rotation, the medium collection area is formed by a region of the bottom of the fluid vessel that has a larger diameter than the aeration and stirring unit. This allows components of a culture that have been separated radially relative to the axis of rotation to be collected in the medium collection area during rotation of the aeration and stirring unit along the axis of rotation.

[0071] Examples of the design of the medium collection area are: circumferential channel in the bottom of the fluid container, conical area in the bottom of the fluid container, valleys in the bottom of the fluid container, although this list is not exhaustive.

[0072] GO / sw 241019DE

[0073] December 17, 2025 In one embodiment of the bioreactor, it is provided that the

[0074] The medium collection area is formed by a bulge in the bottom area.

[0075] The curvature allows for the optimization of flow patterns in the reactor space, especially in combination with a rotational movement of the gassing and stirring unit.

[0076] The curvature can be directed towards the reactor chamber. In this way, the medium collection area can, for example, be designed as a circumferential channel. Alternatively, the curvature can be directed in the opposite direction to the reactor chamber. This allows for the formation of a medium collection area shaped as a local low point.

[0077] The curvature of the bottom sections can correspond to a curve with a radius of curvature. Additionally, the bottom section of the fluid container can have a diameter corresponding to the inner diameter of the fluid container. In one embodiment of the bioreactor, the curvature is designed such that the radius of curvature is equal to or greater than half the diameter of the bottom section, in particular that the radius of curvature is equal to or greater than the diameter of the bottom section, preferably that the radius of curvature is in the range of the diameter of the bottom section up to five times the diameter of the bottom section.

[0078] The specified curvature allows the medium to flow into the medium collection area while minimizing any negative impact on the flow. If the ratio of the curvature radius to the diameter of the base area is greater than specified, the base is too flat to form a medium collection area. If the ratio is smaller than specified, the increased curvature can negatively affect the flow pattern in the reactor chamber and the flow into the membrane module.

[0079] GO / sw 241019DE

[0080] December 17, 2025 In one embodiment of the bioreactor, the medium collection area is formed by an inclination of the bottom area.

[0081] By sloping the bottom of the reactor, the fluid collection area can be designed as a local low point within the reactor chamber. If a fluid outlet is provided at this local low point, emptying the reactor chamber can be facilitated.

[0082] Such a local low point can be formed by the fact that the bottom area meets the cylindrically formed wall area of ​​the fluid container as a planar surface, whereby the planar surface is inclined relative to the main extension direction of the rotational symmetry axis of the wall area.

[0083] In one embodiment of the bioreactor, the gassing and stirring unit is essentially cylindrical with an outer diameter, and the reactor chamber is essentially cylindrical with an inner diameter, and the ratio of the outer diameter of the gassing and stirring unit to the inner diameter of the reactor chamber is in the range of 0.4 to 0.9, in particular in the range of 0.5 to 0.8.

[0084] This method allows for particularly effective control of the flow during rotation of the aeration and stirring unit within the reactor chamber. In particular, it ensures optimal mixing of the fluid within the reactor chamber within the specified ranges. If the ratio of the outer diameter to the inner diameter of the aeration and stirring unit is greater than approximately 0.9, the flow within the reactor will be excessively restricted. If the ratio of the outer diameter to the inner diameter of the aeration and stirring unit is less than approximately 0.4, uniform mixing will be difficult, and the aeration and stirring unit will be undersized.

[0085] GO / sw 241019DE

[0086] December 17, 2025 The cylindrical shape of the aeration and stirring unit can result from the design of one or more individual components of the aeration and stirring unit, such as the at least one membrane element, a mounting element for the at least one membrane element, or a bottom element. Alternatively, the essentially cylindrical shape of the aeration and stirring unit can be determined by a basic form that corresponds to a lateral surface of the aeration and stirring unit.

[0087] In addition, such a design offers sufficient space for the provision of additional elements in the reactor space, such as sensors or probes.

[0088] Furthermore, a radially spiral arrangement or an axial, turbine blade-like arrangement of the at least one membrane element as circular segments and the above-mentioned value ranges for a ratio of the outer diameter of the aeration and stirring unit to the inner diameter can ensure that conditions such as shear forces and oxygen availability can be kept essentially constant.

[0089] It should be noted that in the case of a fluid container manufactured using a mold, for example by means of an injection molding process, the term "essentially cylindrical" can be extended to include a conical shape. The conical shape in such manufacturing processes is due to the necessity of removing the injected material from the mold after cooling. With such a conical shape, the inner diameter of the fluid container, as defined in the present embodiment, can be assumed to be the inner diameter of the fluid container in the region of the membrane element of the aeration and stirring unit, for example, in the region of a bottom element of the aeration and stirring unit or in the region of an equator of the aeration and stirring unit.

[0090] GO / sw 241019DE

[0091] December 17, 2025 In one embodiment of the bioreactor, the aeration and stirring unit is provided to have a bottom element with a main extension plane and with at least one penetrating opening, wherein, viewed in a cross-sectional view parallel to the main extension plane of the bottom element, the penetrating opening has an outer circumference and forms a flowable area A2, the aeration and stirring unit is arranged in the reactor space such that the bottom element is spaced at a distance H from the bottom area of ​​the fluid container, wherein the distance H and the outer circumference of the penetrating opening of the bottom element define a flowable area Al, and the flowable area Al is equal to or larger than the flowable area A2.

[0092] By designing the bioreactor, an optimized fluid transfer can be achieved between a fluid taken up in the reactor chamber and a fluid supplied to the gassing and stirring unit.

[0093] Preferably, the distance H corresponds to the minimum distance between the bottom element of the aeration and stirring unit and the bottom area of ​​the fluid container. In addition, the distance H is preferably adjustable via the length of the drive hollow shaft or via the design of the connection between the drive hollow shaft and the aeration and stirring unit.

[0094] In one embodiment of the method, the first fluid transfer is carried out via a membrane element of the aeration and stirring unit.

[0095] The membrane element enables a diffusive transfer of a first fluid, supplied to the aeration and stirring unit, into a second fluid, contained in the reactor chamber. The present embodiment ensures that a maximum fluid transfer occurs, namely a

[0096] GO / sw 241019DE

[0097] December 17, 2025: Fluid transfer according to the properties of the membrane element. The first, controlled fluid transfer can be supplemented by a second fluid transfer through headspace gassing.

[0098] In one embodiment of the method, it is provided that an overpressure or underpressure is created in the reactor chamber using the second fluid.

[0099] Applying positive pressure within the reactor chamber can increase the solubility of fluids, particularly according to Henry's Law. Applying negative pressure can facilitate the flow of gas through the fluid path or from the aeration and stirring unit.

[0100] The at least one fluid outlet of the cover system can be equipped with a valve or similar device to control pressure in the headspace or reactor space.

[0101] In one embodiment of the method, the gassing and stirring unit is driven in a rotational movement.

[0102] In contrast to an oscillatory movement, which causes strong acceleration or deceleration forces and can therefore have negative effects on cells etc., the rotational movement described above allows for a gentle and essentially uniform circulation or flow pattern of the fluid contained in the reactor space.

[0103] In addition, the rotational movement actively moves at least one membrane element of the aeration and stirring unit through the reactor fluid, ensuring optimal flow around it. This allows concentration gradients at the membrane element to be efficiently reduced and gas input to be increased.

[0104] GO / sw 241019DE

[0105] December 17, 2025. Further features and advantages of the bioreactor and the process will become apparent from the following description of exemplary embodiments, with reference to the attached drawing.

[0106] The drawing shows

[0107] Fig. 1 shows a first embodiment of a bioreactor;

[0108] Fig. 2 shows a detailed view of the bioreactor cover system from Fig. 1;

[0109] Fig. 3 shows an embodiment of one use of the bioreactor from Fig. 1;

[0110] Fig. 4 shows an exemplary embodiment of a basic profile of a bottom area of ​​a fluid container in a schematic view;

[0111] Fig. 5 shows a detailed view of a bottom area of ​​a bioreactor with a gassing and stirring unit and

[0112] Fig. 6 shows an embodiment of a method for gassing a biological system.

[0113] Fig. 1 shows a first embodiment of a bioreactor 100 for aerating a biological system. The bioreactor 100 comprises a fluid vessel 102, a cover system 104, and an aeration and stirring unit 106. Fig. 1 shows the bioreactor 100 in an assembled state. Here, the cover system 104 and the fluid vessel 102 together form a reactor chamber 108 in which the aeration and stirring unit 106 is arranged.

[0114] GO / sw 241019DE

[0115] December 17, 2025. The fluid container 102 has a wall 110 with a bottom section 112 and a wall section 114. The bottom section 112 has a connection section 116 for a flow-tight connection with the wall section 114, as well as a circumferential medium collection section 118, which is formed by a bulge 120 of the bottom section.

[0116] The cover system 104 comprises a fluid inlet 122, a fluid outlet 124, a hollow drive shaft 126 with an inner channel 128, a first cover element 130, and a second cover element 132. The first cover element 130 and the second cover element 132 are connected to each other via a flow-tight connection and together form a cavity 134. The cavity 134 is fluidically connected to the fluid inlet 122, which opens into the cavity 134. Furthermore, the cavity 134 partially surrounds the drive shaft and is fluidically connected to the inner channel 128 of the hollow drive shaft 126 via a penetrating opening 136 in the wall 110 of the hollow drive shaft 126. As a result, the fluid inlet 122, the cavity 134 and the inner channel 128 of the drive hollow shaft 126 are connected to each other in a flow-permeable manner and form a first section of a fluid path of the bioreactor 100.

[0117] The drive hollow shaft 126 has a first distal end 138 for connection to a drive element and a second distal end 140 for connection to the gassing and stirring unit 106. The first distal end 138 is designed for connection to a mechanical drive element. For this purpose, a connecting piece 142 is provided at the first distal end 138 of the drive hollow shaft 126, which is attached to the wall 110 of the drive hollow shaft 126. By attaching the first distal end 138 to the connecting piece 142, the inner channel 128 of the drive hollow shaft 126 is closed at the first distal end 138, preventing flow.

[0118] GO / sw 241019DE

[0119] December 17, 2025 The gassing and stirring unit 106 has a connection area 144 with a fluid inlet 146, at least one membrane element 148 and a fluid outlet 150, wherein the fluid inlet 146, the membrane element 148 and the fluid outlet 150 are connected in a flow-permeable manner and thus form a second section of a fluid path of the bioreactor 100.

[0120] In the assembled state of the bioreactor 100 shown, the aeration and stirring unit 106 is connected via the connection area 144 to the second distal end 140 of the drive hollow shaft 126 of the cover system 104. The inner channel 128 of the drive hollow shaft 126 and the fluid inlet 146 of the aeration and stirring unit 106 are permeably connected to each other. The connection of the aeration and stirring unit 106 to the drive hollow shaft 126 is also designed to transmit a driving force from the drive hollow shaft 126 to the aeration and stirring unit 106.

[0121] Furthermore, the fluid outlet 150 of the aeration and stirring unit 106 opens into the reactor chamber 108. Additionally, the fluid outlet 124 of the cover system 104 is fluidically connected to the reactor chamber 108 by opening into the reactor chamber 108 and being fluidically separated from the cavity 134 of the cover system 104. Thus, the fluid outlet 150 of the aeration and stirring unit 106, the free volume 152 of the reactor chamber 108, and the fluid outlet 124 of the cover system 104 form a third section of a fluid path of the bioreactor 100.

[0122] In the assembled state of the bioreactor 100 shown, the first, second, and third sections of the fluid path are arranged in sequence and connected to each other in a flow-permeable manner. In other words, the fluid inlet 122 of the cover system 104, the cavity 134 of the cover system 104, the inner channel 128 of the drive hollow shaft 126, the fluid inlet 146 of the aeration and stirring unit 106, the at least one membrane element 148, and the fluid outlet 150 of the aeration and stirring unit 106 form a fluid path.

[0123] GO / sw 241019DE

[0124] December 17, 2025 Stirring unit 106, reactor chamber 108 and fluid outlet 124 of the cover system 104 together form a fluid path 154.

[0125] In an alternative design of the bioreactor 100, the fluid outlet 124, which is provided on the cover system 104, could be located in the wall area 114 of the fluid container 102.

[0126] The aeration and stirring unit 106, comprising at least one membrane element 148, is essentially cylindrical with an outer diameter 156. The fluid vessel 102, specifically the wall section 114 of the fluid vessel 102, is also essentially cylindrical. Thus, the reactor chamber 108 is essentially cylindrical with an inner diameter 158. The outer diameter 156 of the aeration and stirring unit 106 is smaller than the inner diameter 158 of the reactor chamber 108, so that the aeration and stirring unit 106 is spaced apart from the wall section 114 of the fluid vessel 102, creating a gap 160. The bioreactor 100 has a sensor 162 located in this gap 160.

[0127] Fig. 2 shows a detailed view of the cover system 104 of the bioreactor 100 from Fig. 1. The reference numerals from the description of Fig. 1 are adopted for the description of corresponding components of the bioreactor 100 in Fig. 2.

[0128] Fig. 2 shows the first cover element 130 and the second cover element 132, as well as the cavity 134 formed by their assembly or connection. The cavity 134 surrounds the drive hollow shaft 126 radially in the section 200 in which the wall 110 of the drive shaft has a penetrating opening 136.

[0129] The first cover element 130 has a first penetrating opening 202 for receiving a first section 204 of the drive hollow shaft 126. Furthermore, the

[0130] GO / sw 241019DE

[0131] On December 17, 2025, the first cover element 130, a first bearing element 206, and a first sealing element 208 were incorporated in such a way that the first cover element 130 and the first area of ​​the drive hollow shaft 126 are rotatably and fluid-tightly connected to each other.

[0132] In addition, the second cover element 132 has a second penetrating opening 210 for receiving a second section 212 of the drive hollow shaft 126. Furthermore, a second bearing element 214 and a second sealing element 216 are received on the second cover element 132 in such a way that the second cover element 132 and the second section of the drive hollow shaft 126 are rotatably and fluid-tightly connected to each other.

[0133] The penetrating opening 136 of the drive hollow shaft 126 is arranged between the first area 204 and the second area 212, and is thus also radially surrounded by the cavity 134.

[0134] Fig. 3 shows an embodiment for the use of the bioreactor 100 from Fig. 1. Here too, the reference numerals from the description of Fig. 1 are adopted for the description of corresponding components of the bioreactor 100 in Fig. 3.

[0135] The reactor chamber 108 is partially filled with a first fluid 300 in the form of a liquid. Accordingly, there is a first volume fraction 302 of the reactor chamber 108, which is occupied by the first fluid 300, and a second volume fraction 304 of the reactor chamber 108 arranged above the first volume fraction 302 in the direction of the gravitational force.

[0136] A second fluid 306 in the form of a gas flows through the fluid path 154 of the bioreactor 100, which passes through the fluid inlet 122 of the cover system 104, the cavity 134 of the cover system 104, the inner channel 128 of the drive hollow shaft 126, the fluid inlet 146 of the gassing and stirring unit 106, the

[0137] GO / sw 241019DE

[0138] December 17, 2025, membrane element 148, the fluid outlet 150 of the gassing and stirring unit 106, the second volume fraction 304 and the fluid outlet 124 of the cover system 104 is formed.

[0139] The second fluid 306 undergoes a first fluid transfer into the first fluid 300 as it passes through the fluid line in the section of the membrane element 148, and a second fluid transfer into the first fluid 300 in the second volume fraction 304 of the reactor chamber 108, at the free surface of the first fluid 300. Both the first and the second fluid transfers occur essentially without bubbles and diffusively.

[0140] In the illustrated embodiment, the membrane element 148 of the aeration and stirring unit 106 is completely immersed in the first fluid 300. A first fluid transfer and a second fluid transfer as described above can also be achieved if the membrane element 148 is partially immersed in the first fluid 300.

[0141] In operation, the gassing and stirring unit 106 is driven for a rotational movement 308 during a pass of the second fluid 306 through the fluid path 154. Thus, the first fluid 300, which has been gassed twice with the second fluid 306, is stirred.

[0142] Fig. 4 shows an embodiment of a basic profile 400 of a bottom area of ​​a fluid container in a schematic view.

[0143] The basic profile 400 is shown in a cross-sectional view for viewing the ground area.

[0144] The basic profile 400 of the bottom area has an edge area 402, 404 and a middle area 406, wherein the edge area 402, 404 is located on both sides of the middle area 406 due to a rotational symmetry of the bottom area.

[0145] GO / sw 241019DE

[0146] December 17, 2025. The central region 406 and part of the edge region 402, 404 together exhibit a curvature corresponding to a radius of curvature n, 408. Furthermore, the bottom region has a diameter da, 410, which corresponds to the inner diameter of the fluid container for which the bottom region is intended. The curvature is designed such that the radius of curvature n, 408 has a value ranging from equal to or greater than half the diameter da, 410 of the bottom region to five times the diameter da, 410 of the bottom region.

[0147] Viewed in the cross-sectional view shown, the curvature forms a slope 412 beyond the central area 406, which descends towards the edge area 402, 404. The base profile 400 rises in the edge area 402, 404 in the opposite direction to the slope 412, with a height hl, 414, i.e., upwards in the present illustration. Thus, the central area 406 and the edge area 402, 404 together form a curvature and a channel 416 surrounding the central area 406, which, when used in a bioreactor with such a bottom area, serves as a medium collection area 420. The channel 416 can be characterized by a radius r2, 418.

[0148] Fig. 5 shows a detailed view of a bottom area 500 of a bioreactor 502 with a gassing and stirring unit 504.

[0149] The illustration shows, in part, a fluid vessel 506 with a wall section 508 and a bottom section 500, as well as a section of the aeration and stirring unit 504. The aeration and stirring unit 504 is arranged in the fluid vessel 506 or in a reactor chamber 510 formed at least partially by the fluid vessel 506.

[0150] Also shown is the connection 512 of the gassing and stirring unit 504 with a drive hollow shaft 514 for the fluid supply of the gassing and stirring unit 504.

[0151] GO / sw 241019DE

[0152] December 17, 2025 The aeration and stirring unit 504 comprises a membrane element 516, a support element 518, and a bottom element 520. The bottom element 520 extends substantially along a principal extension plane 522. Furthermore, the bottom element 520 has a penetrating opening 524 which, viewed in a cross-sectional view parallel to the principal extension plane 522 of the bottom element 520, has an outer circumference 526 and forms a flowable or open area A2, 528.

[0153] The gassing and stirring unit 504 is arranged in the reactor chamber 510 such that the bottom element 520 is spaced at a distance H, 530 from the bottom area 500 of the fluid container 506, wherein the distance H, 530 and the outer circumference 526 of the penetrating opening 524 of the bottom element 520 define a flowable area Al, 532.

[0154] The bottom element 520 of the gassing and stirring unit 504 is designed in such a way or the gassing and stirring unit 504 is arranged in the reactor space 510 in such a way that the flowable area Al, 532 is equal to or greater than the flowable area A2, 528.

[0155] Preferably the distance H, 530 is adjustable via the length of the drive hollow shaft 514 or the design of the connection 512 between the drive hollow shaft 514 and the gassing and stirring unit 504.

[0156] Fig. 6 shows an embodiment of a method 600 for gassing a biological system.

[0157] In a first step 602, a bioreactor with a reactor room and a gassing and stirring unit arranged in the reactor room is provided.

[0158] GO / sw 241019DE

[0159] December 17, 2025. In step 604, the reactor chamber is partially filled with a first fluid, preferably a liquid, such that a first volume fraction of the reactor chamber is occupied by the first fluid. In step 606, a second fluid, preferably gaseous, is introduced into the aeration and stirring unit for a first fluid transfer and is introduced into the first fluid substantially diffusively via the aeration and stirring unit.

[0160] In step 608, the second fluid is introduced from the aeration and stirring unit into a second volume fraction of the reactor chamber, arranged in the direction of gravity above the first volume fraction, and brought into contact with the first fluid at the free surface of the first fluid within the reactor chamber for a second fluid transfer. In steps 606 and 608, the aeration and stirring unit is driven in a rotational motion.

[0161] GO / sw 241019DE

[0162] December 17, 2025

Claims

GO / sw 241019DE 17. December 2025 Please note that 1. Bioreactor (100, 502) for aerating a biological system, comprising a cover system (104), a fluid container (102, 506), and an aeration and stirring unit (106, 504), wherein, in an assembled state of the bioreactor (100, 502), the cover system (104) and the fluid container (102, 506) together form a reactor chamber (108, 510), and the aeration and stirring unit (106, 504) is arranged in the reactor chamber (108, 510), characterized in that the cover system (104) has a fluid inlet (122) and a drive hollow shaft (126, 514) with an inner channel (128), wherein the fluid inlet (122) and the inner channel (128) of the drive hollow shaft (126, 514) are connected in a flow-permeable manner, such that the aeration and stirring unit (106, 504) has a connection area (144) with a fluid inlet (146), at least one membrane element (148, 516) and a fluid outlet (150), wherein the fluid inlet (146), the membrane element (148,516) and the fluid outlet (150) are connected in a flow-permeable manner, and that, in an assembled state of the bioreactor (100, 502), the fluid inlet (122) of the cover system (104), the inner channel (128) of the drive hollow shaft (126, 514), the fluid inlet (146) of the aeration and stirring unit (106, 504), the at least one membrane element (148, 516) and the fluid outlet (150) of the aeration and stirring unit (106, 504) form a fluid path (154) and the fluid outlet (150) of the aeration and stirring unit (106, 504) opens into the reactor chamber (108, 510).

2. Bioreactor (100, 502) according to claim 1, characterized in that the connection area (144) of the gassing and stirring unit (106, 504) is designed for a connection with the drive hollow shaft (126, 514), wherein the connection is designed both for the transmission of a drive force and for the transmission of a fluid to the gassing and stirring unit (106, 504).

3. Bioreactor (100, 502) according to one of the preceding claims, characterized in that the cover system (104) has at least one fluid outlet (124), and that, in an assembled state of the bioreactor (100, 502), the reactor chamber (108, 510) and the at least one fluid outlet (124) of the cover system (104) further form the fluid path (154) adjoining the fluid outlet (150) of the aeration and stirring unit (106, 504).

4. Bioreactor (100, 502) according to one of the preceding claims, characterized in that the cover system (104) comprises a first cover element (130) and a second cover element (132), that the first cover element (130) and the second cover element (132) are connected to each other via a flow-tight connection and together form a cavity (134), that the drive hollow shaft (126, 514) has a wall (110) forming the inner channel (128) with at least one penetrating opening (136), and that the fluid inlet (122) of the cover system (104) and the inner channel (128) of the drive hollow shaft (126, 514) are connected via the cavity (134) and via the at least one penetrating opening (136) in the wall (110) of the drive hollow shaft (126, 514). are connected in a flow-permeable manner. GO / sw 241019DE December 17, 2025 5. Bioreactor (100, 502) according to one of the preceding claims, characterized in that the drive hollow shaft (126, 514) has a first distal end (138) for connection with a drive element and a second distal end (140) for connection with the gassing and stirring unit (106, 504), wherein the first distal end (138) is designed for connection with a mechanical drive element or for connection with a magnetic drive element, and wherein at the first distal end (138) the inner channel (128) of the drive hollow shaft (126, 514) is closed in a flow-impermeable manner.

6. Bioreactor (100, 502) according to one of claims 1 to 4, characterized in that the drive hollow shaft (126, 514) has a first distal end (138) for connection with a magnetic drive element and a second distal end (140) for connection with the gassing and stirring unit (106, 504), wherein at the first distal end (138) the inner channel (128) of the drive hollow shaft (126, 514) is open to allow flow.

7. Bioreactor (100, 502) according to one of the preceding claims, characterized in that the fluid container (102, 506) has a bottom area (112, 500) with a medium collection area (118, 420).

8. Bioreactor (100, 502) according to claim 7, characterized in that the medium collection area (118, 420) is formed by a bulge (120) of the bottom area (112, 500). GO / sw 241019DE December 17, 2025 9. Bioreactor (100, 502) according to claim 7 or 8, characterized in that the medium collection area (118, 420) is formed by an inclination of the bottom area (112, 500).

10. Bioreactor (100, 502) according to one of the preceding claims, characterized in that the aeration and stirring unit (106, 504) is essentially cylindrical with an outer diameter (156), and that the reactor chamber (108, 510) is essentially cylindrical with an inner diameter (158), and that the ratio of the outer diameter (156) of the aeration and stirring unit (106, 504) to the inner diameter (158) of the reactor chamber (108, 510) is in the range of 0.4 to 0.9, in particular in the range of 0.5 to 0.8 11. Bioreactor (100, 502) according to one of the preceding claims, characterized in that the aeration and stirring unit (106, 504) has a bottom element (520) with a main extension plane (522) and with at least one penetrating opening (524), wherein, viewed in a cross-sectional view parallel to the main extension plane (522) of the bottom element (520), the penetrating opening (524) has an outer circumference (526) and forms a flowable area A2 (528), such that the aeration and stirring unit (106, 504) is arranged in the reactor chamber (108, 510) such that the bottom element (520) is spaced at a distance H (530) from the bottom region (112, 500) of the fluid vessel (102, 506), wherein the distance H (530) and the The outer perimeter (526) of the penetrating opening (524) of the bottom element (520) defines a flowable area Al (532), and that the flowable area Al (532) is equal to or larger than the flowable area A2 (528). GO / sw 241019DE December 17, 2025 12. A method for aerating a biological system, in which a bioreactor (100, 502) with a reactor chamber (108, 510) and with an aeration and stirring unit (106, 504) arranged in the reactor chamber (108, 510), in particular a bioreactor (100, 502) according to one of the preceding claims, is provided, in which the reactor chamber (108, 510) is partially filled with a first fluid (300), preferably as a liquid, so that a first volume fraction (302) of the reactor chamber (108, 510) is occupied by the first fluid (300), in which a second fluid (306), preferably gaseous, is introduced into the aeration and stirring unit (106, 504) for a first fluid transfer and passes through the aeration and stirring unit (106, 504) substantially diffusively is introduced into the first fluid (300), in which the second fluid (306) is extracted from the aeration and stirring unit (106,504) is guided in a second volume fraction (304) of the reactor space (108, 510) arranged in the direction of the gravitational force above the first volume fraction (302) and is brought into contact with the first fluid (300) for a second fluid transfer at the free surface of the first fluid (300) in the reactor space (108, 510).

13. Method according to claim 12, wherein the first fluid transfer is carried out via a membrane element (148, 516) of the gassing and stirring unit (106, 504).

14. Method according to one of the preceding claims, wherein an overpressure or underpressure is caused in the reactor space (108, 510) by the second fluid (306).

15. Method according to one of the preceding claims, wherein the gassing and stirring unit (106, 504) is driven in a rotational movement (308). GO / sw 241019DE December 17, 2025

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