Bioreactor system with gas supply system
By designing multiple gas outlet pipelines in the bioreactor system to connect to the gas source and setting up a closed-loop controller for mass flow, the problem of insufficient flexibility in gas delivery is solved, and flexible transportation and precise control of gas is achieved.
Patent Information
- Application Number
- CN202380060709.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-08-19
- Filing Date
- 2023-07-20
- Publication Date
- 2025-03-28
AI Technical Summary
Existing bioreactor systems have insufficient flexibility in gas delivery and cannot flexibly transport different gases into bioreactor vessels.
A bioreactor system is designed, which uses multiple gas outlet pipelines to connect to multiple gas sources. Each gas outlet pipeline is equipped with a mass flow closed loop controller, allowing independent control of the gas delivery path and flow rate.
It realizes flexible gas transportation, and can transport different gases through multiple gas distributors and cover gas outlets at the same time, accurately control gas transportation, and save gas use.
Smart Images
Figure CN119731301A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a bioreactor system for carrying out a bioprocess, the bioreactor system having a gas supply facility. Background Art
[0002] A bioreactor system is generally understood here to mean an apparatus having a container, by means of which a biotechnological process, for example a biopharmaceutical process, can be carried out or supported. In addition to bioreactors, in which microorganisms or mammalian cells are cultured under specific conditions, another example is a process mixing device, by means of which liquid biological media, such as suspensions, solutions, emulsions, etc., can be mixed. The container of a bioreactor system can be a dimensionally stable vessel or a flexible bag.
[0003] Bioreactor systems can be equipped with one or more gas supply devices ("Sparger" in English) in order to introduce air and / or other gases directly into the liquid biological medium present in the container. In the context of cell culture biotechnology, the gas supply controls the air or gas input into the nutrient juice in the interior of the container in an open loop in order to achieve an optimized environment for cell growth. Therefore, in cell culture - in contrast to some bacterial cultures - gas is supplied not only by air, but also by oxygen (O2), nitrogen (N2), carbon dioxide (CO2) and air in a composition optimized for the corresponding cell type and fermentation. Since the pH value in the medium changes during cell growth, but a constant pH value is important for many production processes, the pH value must also be closed-loop controlled. This closed-loop control is usually performed by means of a controlled supply of CO2.
[0004] Typically, a gas supply ring or a gas supply disk is used as a gas supply device, or the gas is directly introduced into the liquid biological medium via a gas outlet pipeline. There is also a combined gas supply device, which has a housing with two gas supply channels in the interior. Via two gas inlet openings in the housing, one or more gases can be introduced into the associated gas supply channels of the housing respectively. The first gas supply channel is associated with a plurality of larger gas outlet openings with a diameter greater than 0.2 mm, for example, 0.8 mm, and the second gas supply channel is associated with a plurality of smaller gas outlet openings with a smaller diameter, for example, 0.15 mm or less. The combined gas supply device can therefore selectively be used as a so-called "annular gas distributor" with a larger opening and as a "micro gas distributor" with a smaller opening.
[0005] Additionally, gas can be fed from above into the bioreactor container, more precisely into the space above the medium. This so-called "cover ventilation" or head supply can be done for various reasons, in particular to ensure that the bag remains inflated when using a bioreactor system with a flexible bag.
[0006] In order to deliver different gases to the bioreactor container, a gas delivery station with a gas pipeline is usually provided, which leads from the corresponding gas source to the gas outlet in the container, that is - as long as it is provided - to the annular gas distributor and the micro gas distributor and to the cover gas outlet, wherein the annular gas distributor and the micro gas distributor share a gas pipeline. A mass flow closed-loop controller can be used for open-loop control of the total amount of delivery, and a stop valve can be used for switching the flow path (from the corresponding gas source to the desired gas outlet). In this traditional configuration, it must be decided in advance for a specific gas whether it is delivered via an annular gas distributor or via a micro gas distributor or delivered to the cover gas outlet. The corresponding flow path is released by correspondingly switching the stop valve. However, the feasibility of the gas supply is limited thereby. Summary of the invention
[0007] The object of the invention is to enable a flexible supply of gas into a bioreactor container.
[0008] This object is achieved by a bioreactor system having the features of claim 1. Advantageous and suitable embodiments of the bioreactor system according to the invention are specified in the dependent claims.
[0009] The bioreactor container for carrying out a bioprocess according to the invention comprises a container for containing a liquid biological medium and a gas supply facility for controlled delivery of different gases from a gas source into the container. The gas supply facility has a plurality of gas outlet pipelines, which are connected to a gas outlet of a cover in one or more gas supply devices and / or in the interior of the container. Each gas outlet pipeline is connected to a plurality of gas sources via a respective gas delivery pipeline or a respective branch of a gas delivery pipeline. A mass flow closed-loop controller connected to an open-loop control unit is arranged in each gas delivery pipeline and in each branch.
[0010] According to this configuration of the gas supply facility of the bioreactor system of the present invention, it is therefore proposed that each connection between the gas source and the gas outlet pipeline is provided with its own mass flow closed-loop controller, via which the gas is delivered to the bioreactor container. The gas outlet pipeline of the gas supply facility is typically connected to a gas supply device in the form of a gas distributor, especially an annular gas distributor or a micro gas distributor or a combined gas distributor and / or to a cover gas outlet. Therefore, each gas distributor and each cover gas outlet can be supplied with gas separately. It is also possible to provide a mass flow closed-loop controller in all connections to simultaneously and individually closed-loop control a gas type (e.g. oxygen) via multiple gas distributors, especially annular gas distributors and micro gas distributors and, if necessary, other gas distributors (other types) and / or other gas outlet pipelines to the bioreactor container. It is also feasible to mix different gases in variable proportions.
[0011] Further advantages of this bioreactor configuration are more precise and finer closed-loop control of the gas delivery, which allows targeted setting of the bubble size and number of bubbles and saves gas.
[0012] In a preferred embodiment of the bioreactor system according to the present invention, the first gas outlet pipeline leading to the annular gas distributor is connected to an air source and / or an oxygen source and / or a nitrogen source and / or a carbon dioxide source. The second gas outlet pipeline leading to the mixed gas distributor is preferably connected to an air source and / or an oxygen source. The third gas outlet pipeline leading to the cover gas outlet is preferably connected to an air source and / or a carbon dioxide source.
[0013] According to an independent inventive aspect, a bioreactor system for carrying out a bioprocess, in particular a bioreactor system of the type described above, comprises an open-loop control mechanism, the open-loop control mechanism comprising a main closed-loop controller for a closed-loop control variable, at least one sensor associated with the main closed-loop controller, and one or more servo closed-loop controllers with a regulating element, the regulating variable of which affects the closed-loop control variable in a targeted manner. The open-loop control mechanism is configured so that a desired value for the closed-loop control variable can be preset for the main closed-loop controller, at least one sensor is used to repeatedly determine the actual value of the closed-loop control variable, and the main closed-loop controller provides an output signal related to the deviation of the actual value of the closed-loop control variable from the desired value of the closed-loop control variable to the servo closed-loop controller. An open-loop control curve is assigned to the servo closed-loop controller, the open-loop control curve being related to the output signal of the main closed-loop controller. According to a first alternative, the open-loop control curve contains a desired value for the regulating element of the servo closed-loop controller, and the open-loop control mechanism is configured so that the desired value for the regulating element can be input in the physical unit of its regulating variable. According to a second alternative, the open-loop control curve contains a desired value for a parameter directly related to the bioprocess and influencingable in a targeted manner by the control element, and the open-loop control is configured such that it automatically assigns a desired value for the control element of the servo closed-loop controller to the parameter desired value.
[0014] Due to the open-loop control mechanism configured according to the present invention, the user does not have to consider and input abstract data in general units, such as percentage values of the output signal of the servo closed-loop controller.
[0015] More precisely, according to the first alternative of the invention, the user can input real physical values for the desired values of regulating elements, such as a mass flow closed-loop controller of an agitator and a gas supply facility arranged in a bioreactor container, without having to consider which output value of the servo closed-loop controller corresponds to a specific rotational speed of the agitator or gas supply rate.
[0016] According to a second alternative of the invention, the user input is less abstract, ie the user predetermines the desired values for process-related, ie process-characterizing, parameters, for example for the volume-dependent mass transfer coefficient (k L The desired value of the parameter a) is determined by the open-loop control mechanism. The open-loop control mechanism then automatically uses the open-loop control curve associated with the value for the open-loop control of the regulating elements of the servo closed-loop controller, in particular the agitator and the mass flow closed-loop controller. This is particularly advantageous in the case where the user has already developed the bioprocess on a small scale in the laboratory and does not know how to set the regulating elements of the large bioreactor system when it is expanded to a large production scale in order to achieve and maintain the same parameter values. This is done automatically by the open-loop control mechanism coordinated with the large bioreactor system; the user only has to enter the desired parameter value.
[0017] Besides the advantages mentioned, the invention very clearly helps to reduce the risk of erroneous inputs.
[0018] As process-related parameter values input by the user instead of percentage values for the servo closed-loop controller, in particular values for one of the following parameters are considered: cell growth rate, cell density, oxygen transfer rate, oxygen absorption rate, bubble size, number of bubbles, mixing time, volume-related mass transfer coefficient.
[0019] The parameters are important parameters that characterize their processes from the user's perspective. For example, bubble size has a significant impact on how oxygen is distributed in a bioreactor container. In the case of the small bubbles produced by a micro gas distributor, surface tension is the dominant force. It therefore has a long residence time in the reactor, which improves oxygen mass transfer (oxygen input), but it is not so suitable for removing carbon dioxide from the culture. The larger bubbles produced by an annular gas distributor have a short residence time, but they are not so easily dissolved compared to smaller bubbles. It is particularly used to remove CO2.
[0020] In particular, dissolved oxygen is suitable as a closed-loop control variable for a main closed-loop controller for a bioreactor system, since a corresponding sensor is usually always available. However, the closed-loop control variable can in principle also be another parameter that can be measured directly by means of at least one sensor, for example one of the following parameters: carbon dioxide content, cell number, cell density, viable cell volume, turbidity, glucose content, pH value, carbon dioxide partial pressure, oxygen partial pressure.
[0021] According to a refinement of the invention, the closed-loop control variable can even be a parameter that cannot be directly measured by means of at least one sensor, but can be determined by means of at least one sensor, such as one of the following parameters: oxygen transmission rate, oxygen absorption rate, cell growth rate, glucose consumption rate, carbon dioxide production rate, carbon dioxide emission rate, respiratory quotient, biomass yield, glucose yield, yield of other carbon dioxide sources or nitrogen sources. In order to determine the actual value of the parameter, calculations are additionally performed and / or mathematical models created in advance are used. The sensor and the required auxiliary mechanisms can in this case be collectively referred to as "soft sensors".
[0022] In a preferred embodiment of the bioreactor system according to the invention, the regulating elements include a plurality of mass flow closed-loop controllers of an agitator and a gas supply facility arranged in the container of the bioreactor system. The open-loop control mechanism can then be configured according to the first alternative of the invention so that a value in the unit of U / min (revolutions per minute) can be input as a desired value for the agitator and a value in the unit of L / min (liters per minute) can be input as a desired value for the mass flow closed-loop controller. This of course includes units derived or derivable therefrom, such as, for example, U / sec (revolutions per second) or mL / sec (milliliters per second), etc., because these are always still the units of the regulating variables of the agitator or mass flow closed-loop controller - as opposed to percentage values with respect to the closed-loop control range of the corresponding servo closed-loop controller).
[0023] The open-loop control curve assigned to the servo closed-loop controller and related to the output signal of the main closed-loop controller can be stored directly in the open-loop control mechanism or in an external database accessed by the open-loop control mechanism. The open-loop control curve itself can be preset by the manufacturer or the user, or it can be pre-set individually by the user.
[0024] Preferably, the open-loop control curve is based on empirically determined values or on a mathematical model created beforehand.
[0025] A further development of the invention provides that the open-loop control device monitors the input of desired values for the regulating elements of the servo closed-loop controller, in particular the stirrer and the mass flow closed-loop controller, so that no desired value combinations are input that would lead to abnormal operation of the bioreactor system. In particular, flooding or an unnecessarily high power input when no gas is supplied can thereby be avoided.
[0026] In addition, the time sequence (starting time) and the actuation of the corresponding control elements can be automatically preset by means of the open-loop control mechanism. For example, by starting the gas supply first and then starting the stirring, a higher k L a value and more uniform bubble distribution. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Other features and advantages of the present invention are apparent from the following description and the accompanying drawings to which reference is made. In the accompanying drawings:
[0028] Figure 1 A bioreactor system with gas supply facilities is shown;
[0029] Figure 2 A greatly simplified view of the gas supply system is shown;
[0030] Figure 3 A circuit diagram showing a conventional open-loop control of gas delivery for a bioreactor system;
[0031] Figure 4 A circuit diagram showing an open-loop control of gas delivery for a bioreactor system according to the present invention;
[0032] Figure 5 Shown are open-loop control curves coordinated with closed-loop control variables for actuating various control elements during a bioprocess. DETAILED DESCRIPTION
[0033] exist Figure 1 1 shows an exemplary embodiment of a bioreactor system 10 for culturing cells, which comprises a container 12, here in the form of a disposable flexible bag. The container 12 is provided for containing a substantially liquid biological medium, which serves as a nutrient medium.
[0034] The bioreactor system 10 further comprises an agitator 14, which is installed inside the container 12. The agitator 14 has an agitator shaft 16, on which one or more agitation mechanisms 18 are arranged. The agitator 14 is used, in particular, to mix the biological medium during cultivation.
[0035] As in Figure 1 As shown in FIG. 1 , the bioreactor system 10 further comprises a gas supply device 20 arranged in the container 12 , and the gas supply device is used to deliver more gases, in particular oxygen, carbon dioxide, nitrogen and air, to the biological medium.
[0036] As indicated Figure 2 As can be seen in the figure, the gas supply device 20 has a plurality of, here two, mutually separated gas supply channels 22, 24, which are formed within a housing 26. A gas inlet is formed in the housing 26 for each gas supply channel 22, 24, through which gas can be introduced into the corresponding gas supply channel 22, 24. In the installed and ready-to-operate state, each gas inlet is in fluid connection with a corresponding gas source via a corresponding gas outlet line 28, 30.
[0037] Furthermore, the housing 26 has a plurality of gas outlet openings 34 , 36 , via which gas can be discharged from the respective gas supply channel 22 , 24 into the liquid biomedium surrounding the gas supply device 20 in the interior of the container 12 .
[0038] In the embodiment shown, the outer first air supply channel 22 has a diameter greater than 0.2 mm, preferably 0.25 mm to 4.0 mm, or a cross section greater than 0.03 mm. 2 , preferably 0.05mm 2 Up to 12.0mm 2The second gas supply channel 24 has a maximum diameter of 0.2 mm, preferably 0.005 mm to 0.2 mm or a maximum cross-section of 0.03 mm. 2 , preferably 0.00002mm 2 To 0.03mm 2 The first gas supply channel 22 is referred to as the annular gas distributor 22 and the second gas supply channel 24 is referred to as the micro gas distributor 24 for simplicity.
[0039] In addition to the gas supply device 20, there is a Figure 1 A cover gas supply device (not shown) is provided, wherein air or carbon dioxide can be supplied via a further gas outlet line 3 which opens into the gas outlet in the space above the liquid biomedium.
[0040] exist Figure 3 2 shows an example of a circuit diagram for a conventional gas delivery station with four different gas sources 38 , 40 , 42 , 44 (air, oxygen, nitrogen and carbon dioxide).
[0041] The gas delivery line 46 leads from the gas source 38 to the first gas outlet line 28, which leads to the annular gas distributor 22. The first branch 48 leads from the gas delivery line 46 to the second gas outlet line 30, which leads to the micro gas distributor 24. The second branch 50 leads from the air delivery line 46 to the third gas outlet line 32, which leads to the cover gas outlet.
[0042] The oxygen delivery line 52 leads from the oxygen source 40 to the first gas outlet line 28, which leads to the annular gas distributor 22. The third branch 54 leads from the oxygen delivery line 52 to the second gas outlet line 30, which leads to the micro gas distributor 24.
[0043] A nitrogen delivery line 56 leads from the nitrogen source 42 to the first gas outlet line 28 , which opens into the annular gas distributor 22 .
[0044] A carbon dioxide delivery line 58 leads from the carbon dioxide source 44 to the first gas outlet line 28, which opens into the annular gas distributor 22. A fourth branch 60 leads from the carbon dioxide delivery line 58 to the third gas outlet line 32, which opens into the cover gas outlet.
[0045] As a whole, six mass flow closed-loop controllers 62 connected to the open-loop control mechanism are provided, and the mass flow closed-loop controllers are arranged at the following positions: 1) in the air delivery pipeline 46 between the first branch 48 and the second branch 50; 2) in the oxygen delivery pipeline 52 upstream of the third branch 54; 3) in the nitrogen delivery pipeline 56; 4) in the carbon dioxide delivery pipeline 58 downstream of the fourth branch; 5) in the second branch 50; 6) in the fourth branch 60.
[0046] In addition, according to Figure 3 According to the circuit diagram, four switching valves 64 are arranged at the following positions: 1) in the air delivery pipeline 46 downstream of the mass flow closed-loop controller 62 and the first branch 48; 2) in the oxygen delivery pipeline 52 downstream of the mass flow closed-loop controller 62 and the third branch 54; 3) in the first branch 48; 4) in the third branch 54. The switching valves 64 are switched alternately as needed, so that the corresponding gas is guided to the annular gas distributor 22 or to the micro gas distributor 24.
[0047] Furthermore, each of the three gas outlet lines 28 , 30 , 32 can be blocked and released respectively by means of a block valve 66 , typically a solenoid valve.
[0048] In order to, for example, achieve the delivery of oxygen to a liquid biological medium contained in a container 12 of a bioreactor system 10 via a micro gas distributor 24, a suitable flow rate must be set in the oxygen delivery line 52 at the mass flow closed-loop controller 62, and it must be ensured that the switching valve 64 arranged downstream of the third branch 54 is closed, while the switching valve 64 in the third branch 54 and the shut-off valve 66 in the second gas outlet line 30 are open.
[0049] Figure 4 The circuit diagram for gas delivery of the bioreactor system 10 according to the invention is shown by way of example. The extension of the pipelines 28, 30, 32, 46, 52, 56, 58 and the branches 48, 50, 54 and 60 is in principle the same as in the above-mentioned gas delivery station, which can be designed as a module of the bioreactor system 10. A shutoff valve 66 can also be provided for shutting off and releasing the three gas outlet pipelines 28, 30, 32, but without a switching valve 64. For this purpose, eight mass flow closed-loop controllers 62 connected to an open-loop control mechanism are used as a whole, which are arranged in all four gas delivery pipelines 46, 52, 56, 58 of the gas sources 38, 40, 42, 44 and in all four branches 48, 50, 54, 60. This means that a mass flow closed-loop controller 62 is provided in each gas section.
[0050] With the configuration described, it is possible to individually open-loop control the delivery of all gases to the annular gas distributor 22 and the delivery of air and oxygen to the micro gas distributor 24 and to the cover gas outlet. In particular, since the mass flow closed-loop controller 62 can individually set for each gas whether it is delivered to the corresponding gas outlet pipeline 28, 30, 32 and with what mass flow rate it is delivered to the corresponding gas outlet pipeline 28, 30, 32. In particular, it is possible to deliver gas to multiple gas outlet pipelines 28, 30, 32 at the same time. For example, oxygen can be delivered to the annular gas distributor 22 and the micro gas distributor 24 at different mass flow rates at the same time.
[0051] Of course, it is also possible to provide more or fewer and / or other gas sources. It is also possible to provide more or fewer gas outlet lines, which lead to the gas distributor or directly to the liquid biological medium or are provided for the gas supply of the cover. It is important that a dedicated mass flow closed-loop controller 62 is provided for each gas supply to the gas outlet line provided.
[0052] In which, for example, according to Figure 4 In the configuration described above, each gas delivery line 46, 52, 56, 58 from the gas source 38, 40, 42, 44 to the gas outlet line 28, 30, 32 and each branch 48, 50, 54, 60 that also establishes a connection between the gas source 38, 40, 42, 44 and the gas outlet line 28, 30, 32 is provided with its own mass flow closed-loop controller 62, or in the configuration described above, according to the exemplary embodiment of the present invention, Figure 3 In the conventional configuration described, a special open loop control mechanism can be used as described below.
[0053] The measurement and closed-loop control system (not shown separately in the figure), which is referred to below for simplicity as an “open-loop control mechanism” (open-loop controller), comprises a main closed-loop controller with at least one associated sensor and a plurality of servo closed-loop controllers with regulating elements that can be controlled simultaneously in principle, in this case in particular the stirrer 14 and the mass flow closed-loop controller 62. Further sensors can be associated with the servo closed-loop controllers.
[0054] The at least one sensor associated with the main closed loop controller is typically a sensor for measuring dissolved oxygen (DO sensor).
[0055] The open-loop control mechanism is configured so that a desired value to be kept constant for a closed-loop control variable monitored during the process can be input by a user for the execution of a bioprocess (or a bioprocess step). In the example described here, the user can input a desired value for dissolved oxygen. The open-loop control mechanism has a DO sensor for continuously monitoring (repeatedly performing measurements) said parameter and has a closed-loop controller for said closed-loop control variable (DO closed-loop controller), said closed-loop controller generating an output signal that is correlated with a deviation of an actual value of the closed-loop control variable determined by means of the sensor from a desired value of the closed-loop control variable set by the user.
[0056] The DO closed-loop controller works as a master closed-loop controller, i.e., it acts on one or more servo closed-loop controllers for controlling regulating elements according to the configuration, and the regulating elements can specifically influence the DO value in the process. In the event of a deviation from the desired value, the master closed-loop controller provides an output signal (master variable) to the servo closed-loop controller, which is compared with the closed-loop control range (0%...100%). The servo closed-loop controller controls its regulating elements (here in particular the agitator 14 for mixing and the mass flow closed-loop controller 62 for gas supply) according to the output signal. More precisely, an open-loop control curve is saved for each servo closed-loop controller, which presets its closed-loop control performance according to the output signal of the master closed-loop controller.
[0057] In the example observed here, a plurality of (e.g. five) desired values can be assigned to each servo closed-loop controller, which are related to the output signal of the main closed-loop controller. For example, for the output values of the main closed-loop controller 0%, 10%, 20%, 30%, 40% and 50%, the desired values for the regulating elements of the servo closed-loop controller can be entered respectively. Usually, the user presets the desired values himself. However, the expected values can also be preset by the manufacturer and stored in the memory of the open-loop control mechanism. The expected values can also be stored in an external database accessed by the open-loop control mechanism. The expected values for the servo closed-loop controller are coordinated with the specific bioreactor configuration and are based on empirical values and / or mathematical analysis models, which are created by a comprehensive method technology characterization.
[0058] The peculiarity of the open-loop control mechanism is that the desired values for the servo closed-loop controller do not have to be entered as abstract output values relative to its closed-loop control range (0% ... 100%). Rather, the desired values can be entered in the physical units of the corresponding manipulated variables. In the example considered here, the user can therefore enter a specific rotational speed (U / min) for the agitator 14 and a specific air supply rate (L / min) for the mass flow closed-loop controller 62 for different output values of the DO closed-loop controller. The desired values determined in this way can be graphically displayed as a polygon chain with respect to the output signal of the main closed-loop controller, as for example in Figure 5 , where the x-axis indicates the output of the main closed-loop controller and the y-axis indicates the associated manipulated variable of the control element in the physical unit of the corresponding manipulated variable.
[0059] As a safety function of the open-loop control, it can be provided that, when the input of desired values for the stirrer 14 and the mass flow closed-loop controller 62 would lead to an excessively high gas input or an excessively high stirring speed and thus to so-called "Impeller Flooding", an alarm is output or even the input of such values is not accepted in the first place. In the same way, a response can be made to inputs which would lead to an unnecessarily high power input when no gas is supplied.
[0060] Referring to the example considered here, in operation, that is, during the process, the DO value measured by the DO sensor is repeatedly compared with the expected value preset by the user, and the DO closed-loop controller outputs an output signal relative to its closed-loop control range corresponding to the determined deviation. The servo closed-loop controller automatically closes the agitator 14 and the mass flow closed-loop controller 62 to the expected value set for the output value of the DO closed-loop controller so that the DO value is maintained.
[0061] exist Figure 5In the graphical representation of a plurality of polygonal chains shown by way of example, closed-loop control is performed to the desired values for the closed-loop control variables preset by the user by correspondingly controlling the stirrer 14 and the mass flow closed-loop controller 62, so that the stirrer speed (topmost diagram) is kept at 160 U / min with respect to the entire interesting closed-loop control range of the main closed-loop controller (here 0% to 50%). The nitrogen delivery via the annular gas distributor 22 (second diagram from the top) is 10 L / min at an output value of 0% of the main closed-loop controller and is 0 from an output value of 10% of the main closed-loop controller, i.e., nitrogen delivery is no longer performed in the case of greater deviations. Air is delivered not only via the annular gas distributor 22 (third diagram from the top) but also via the micro gas distributor 24 (fourth diagram from the top). The corresponding desired values are similar, but are offset with respect to the output value of the main closed-loop controller. Different polygonal chains are provided for the delivery of carbon dioxide via the annular gas distributor 22 (fifth diagram from the top) and the micro gas distributor 24 (sixth diagram from the top).
[0062] According to another embodiment of the open-loop control mechanism, the output value of the main closed-loop controller is not linked to the desired value of the manipulated variable for the control element, but to at least one desired value for the following parameter, which is directly related to the process and can be influenced in a targeted manner by means of the control element. In other words: the user does not link different output values of the main closed-loop controller to desired values for the stirrer 14 and the mass flow closed-loop controller 62, but simply enters the desired value for the parameter that can be open-loop controlled by the control element, such as the desired cell growth rate, cell density, oxygen transmission rate (OTR), oxygen absorption rate (OUR), bubble size, number of bubbles, mixing time or the desired volume-related mass transfer coefficient (k L a value).
[0063] Users usually rely on these parameters. L The a value is of great significance in biotechnological processes, for example, because it provides an indication of how well the microorganisms in the container 12 of the bioreactor system 10 can be supplied with gas. When cultivating aerobic microorganisms, it is important to achieve a high k for oxygen. L a value, while in autotrophic microorganisms, k for hydrogen and carbon dioxide L The a value is also of great significance.
[0064] If a user develops a process on a laboratory scale in a small bioreactor, he knows the optimized values for one or more of these parameters. However, the settings required for the regulating elements, in particular the stirrer and the mass flow closed-loop controller, in order to achieve the desired parameter values cannot be transferred 1:1 to a large-volume process in a large bioreactor with other regulating elements, in particular a larger stirrer 14 and gas distributors 22, 24. This means that in order to achieve the desired parameter values, other desired values must be preset for the regulating elements, which the user must first find empirically.
[0065] The open-loop control mechanism takes over the work. The user only inputs the desired parameter value as the expected value (e.g. k L The open-loop control mechanism assigns an open-loop control curve to the parameter desired value, by means of which the parameter desired value is realized by means of a large bioreactor on a production scale. The open-loop control curve includes the desired value for the servo closed-loop controller regulating element, as described above. The association of the servo closed-loop controller desired value with the desired parameter value is in turn based on an analytical model, which was created by a comprehensive methodological characterization. For example, for different k L The a values respectively store the desired values for the stirrer 14 and the mass flow closed-loop controller 62, which are coordinated with the current bioreactor configuration. The basis for this is that k L The a value is dependent inter alia on the stirrer rotation speed and the contact area with the air (bubble size).
[0066] According to a development of the open-loop control mechanism, it is also possible to use a parameter other than the Do value measured by the DO sensor as a closed-loop control variable for the closed-loop control process. As closed-loop control variables, the following parameters that can be monitored directly during the process with the aid of corresponding sensors are particularly suitable: CO2 content, cell mass, cell density, viable cell volume, turbidity, glucose content, pH value, carbon dioxide partial pressure (pCO2), oxygen partial pressure (pO2).
[0067] It is also possible to use as closed-loop control variables for a closed-loop control process parameters which cannot be measured directly by means of sensors, but which are calculated from the measured values of one or more sensors or can be determined by means of previously created models. These parameters include, in particular, the oxygen transmission rate (OTR), the oxygen absorption rate (OUR), the cell growth rate, the glucose consumption rate, the carbon dioxide production rate (CER) and emission rate, the respiratory quotient (RQ value), the biomass yield, the glucose yield and, in general, the yield of other carbon dioxide or nitrogen sources. The hardware (one sensor or multiple sensors) and the software (algorithms, allocation tables, etc.) required to determine such parameters during the process can be collectively referred to as "soft sensors".
[0068] It is also possible, alternatively or additionally, to take into account measured values of an off-gas sensor which measures, for example, the oxygen or carbon dioxide content of off-gas drawn off from the container 12 of the bioreactor system 10 .
[0069] It is also possible to consider using spectroscopic analysis equipment (e.g. IR, UV / VIS, Raman spectrometers, etc.) as "sensors" for determining closed-loop control variable parameters. Similarly, devices for measuring substances that exchange substances with cells or serve as inducers for gene expression (e.g. lactic acid, methanol / ethanol, etc.) in bioreactor containers can be used as sensors.
[0070] In addition, the open-loop control mechanism can be configured so that the user can set an uneven or uniform bubble pattern according to the application of parameters. An uneven bubble pattern ensures more efficient mixing, and a uniform bubble pattern ensures improved gas transmission. The gas supply rate (mass flow rate) and the agitator speed are automatically coordinated by the open-loop control mechanism to produce the desired bubble pattern.
[0071] The closed-loop control process for closed-loop control variables that differ from the DO value is carried out in principle in the same way as described above, i.e. for the desired value of such a closed-loop control variable, the desired value for the regulating element of the servo closed-loop controller or the desired value for the parameter directly related to the process can be entered in the physical unit of the corresponding manipulated variable. In the latter case, the open-loop control mechanism automatically assigns the adapted desired value for the regulating element.
[0072] Depending on the control variable, a servo closed-loop controller can be provided which, in addition to or as an alternative to the stirrer 14 and the mass flow closed-loop controller 62 , has further control elements, such as a pump for conveying a medium, such as a nutrient solution or a buffer.
[0073] The input of desired values for the closed-loop control variable(s) and desired values for the control elements of the servo closed-loop controller or desired values for process-related parameters, which are dependent on the output values of the main closed-loop controller, can be carried out via a software layer located on a conventional controller. However, the open-loop control can also be designed specifically from the outset to process such input desired values.
[0074] The configuration of the gas supply and the open-loop control described as an example is in principle applicable to all bioreactor sizes.
[0075] List of reference numerals:
[0076] 10 Bioreactor System
[0077] 12 Containers
[0078] 14. Blender
[0079] 16 Agitator shaft
[0080] 18. Mixing mechanism
[0081] 20 Gas supply equipment
[0082] 22 (external) first gas supply channel; annular gas distributor
[0083] 24 (internal) second gas supply channel; micro gas distributor
[0084] 26 Shell
[0085] 28 First gas outlet pipeline (annular gas distributor)
[0086] 30 Second gas outlet pipeline (micro gas distributor)
[0087] 32 Third gas outlet pipeline (cover)
[0088] 34 Gas outlet of the first gas supply channel
[0089] 36 Gas outlet of the second gas supply channel
[0090] 38 Air Source
[0091] 40 Oxygen source
[0092] 42 Nitrogen source
[0093] 44 Carbon dioxide source
[0094] 46 air delivery pipeline
[0095] 48 First Branch
[0096] 50 Second Branch
[0097] 52 oxygen delivery pipeline
[0098] 54 Third Branch
[0099] 56 Nitrogen delivery pipeline
[0100] 58 Carbon dioxide delivery pipeline
[0101] 60 Fourth Branch
[0102] 62 Mass Flow Closed Loop Controller
[0103] 64 switching valve
[0104] 66 Solenoid Valve
Claims
1. A bioreactor system (10) for performing a bioprocess, the bioreactor system comprising: a container (12) for containing a liquid biological medium, and a gas supply facility for controlled delivery of different gases from gas sources (38, 40, 42, 44) into the container (12), The gas supply facility has a plurality of gas outlet pipes (28, 30, 32), which open into one or more gas supply devices (20) and / or into a cover gas outlet in the interior of the container (12). Each gas outlet pipeline (28, 30, 32) is connected to a plurality of gas sources (38, 40, 42, 44) via a respective gas delivery pipeline (46, 52, 56, 58) or a respective branch (48, 50, 54, 60) of a gas delivery pipeline (46, 52, 56, 58), and A mass flow closed-loop controller (62) connected to an open-loop control mechanism is provided in each gas delivery pipeline (46, 52, 56, 58) and in each branch portion (48, 50, 54, 60).
2. The bioreactor system (10) according to claim 1, It is characterized in that The first gas outlet pipeline (28) leading to the annular gas distributor (22) is connected to an air source (38) and / or an oxygen source (40) and / or a nitrogen source (42) and / or a carbon dioxide source (44).
3. The bioreactor system (10) according to claim 1 or 2, It is characterized in that The second gas outlet pipeline (30) leading to the micro gas distributor (24) is connected to an air source (38) and / or an oxygen source (40).
4. The bioreactor system (10) according to any one of the preceding claims, It is characterized in that The third gas outlet line (32) leading to the gas outlet of the cover is connected to an air source (38) and / or a carbon dioxide source (44).
5. A bioreactor system (10) for carrying out a bioprocess, in particular according to any of the preceding claims, It is characterized in that An open-loop control mechanism is provided, which comprises a main closed-loop controller for a closed-loop control variable, at least one sensor associated with the main closed-loop controller and one or more servo closed-loop controllers with regulating elements (14, 62), the regulating variables of which influence the closed-loop control variable in a targeted manner, The open-loop control mechanism is configured such that - being able to preset a desired value for the closed-loop control variable for the main closed-loop controller, - using the at least one sensor for repeatedly determining an actual value of the closed-loop control variable, and - the main closed-loop controller provides an output signal related to the deviation of the actual value of the closed-loop control variable from the desired value of the closed-loop control variable to the servo closed-loop controller, wherein an open-loop control curve is assigned to the servo closed-loop controller, the open-loop control curve being related to the output signal of the main closed-loop controller, and wherein the open-loop control curve contains a desired value for the regulating element (14, 62) of the servo closed-loop controller, and the open-loop control mechanism is configured so that the desired value for the regulating element (14, 62) can be input in the physical unit of its regulating variable, or The open-loop control curve contains a desired value for a parameter which is directly related to a biological process and can be specifically influenced by the regulating element (14, 62), and the open-loop control mechanism is configured so that it automatically assigns a desired value for the regulating element (14, 62) of the servo closed-loop controller to the desired parameter value.
6. The bioreactor system (10) according to claim 5, It is characterized in that The parameter is one of: cell growth rate, cell density, oxygen transfer rate, oxygen absorption rate, bubble size, number of bubbles, mixing time, volume-dependent mass transfer coefficient.
7. The bioreactor system according to claim 5 or 6, It is characterized in that The closed-loop control variable is a parameter that can be directly measured by means of the at least one sensor, in particular at least one of the following parameters: dissolved oxygen, carbon dioxide content, cell number, cell density, viable cell volume, turbidity, glucose content, pH value, carbon dioxide partial pressure, oxygen partial pressure.
8. The bioreactor system (10) according to claim 5 or 6, It is characterized in that The closed-loop control variable is a parameter that cannot be directly measured with the aid of the at least one sensor but can be determined with the aid of the at least one sensor, in particular at least one of the following parameters: oxygen transfer rate, oxygen absorption rate, cell growth rate, glucose consumption rate, carbon dioxide production rate, carbon dioxide emission rate, respiratory quotient, biomass yield, glucose yield, and the yield of a carbon dioxide source or a nitrogen source.
9. The bioreactor system (10) according to any one of claims 5 to 8, It is characterized in that The regulating element includes a stirrer (14) and a plurality of mass flow closed-loop controllers (62) of a gas supply facility arranged in a container (12) of the bioreactor system, and the open-loop control mechanism is configured so that a value in units of U / min can be input as a desired value for the stirrer (14), and a value in units of L / min can be input as a desired value for the mass flow closed-loop controller.
10. The bioreactor system (10) according to any one of claims 5 to 9, It is characterized in that The open-loop control curve is stored in the open-loop control mechanism.
11. The bioreactor system (10) according to any one of claims 5 to 9, It is characterized in that The open-loop control curve is stored in an external database accessed by the open-loop control mechanism.
12. The bioreactor system (10) according to any one of claims 5 to 11, It is characterized in that The open-loop control curve is based on empirical values or a mathematical model.
13. The bioreactor system (10) according to any one of claims 5 to 12, It is characterized in that The open-loop control mechanism monitors the input of desired values for the servo closed-loop controller, in particular the agitator (14) and the mass flow closed-loop controller (62), so that no desired value combination that would cause abnormal operation of the bioreactor system (10) is input.