Bioreactor systems and methods of bioprocessing

Abstract

The bioreactor system includes a vessel having a bottom bed, a flexible bioprocessing bag disposed within the vessel, and a flexible bladder disposed intermediate the bottom bed of the vessel and the bioprocessing bag, the flexible bladder being selectively inflatable to change at least one of the shape or configuration of the bioprocessing bag to improve drainage or increase the turndown ratio for the bioreactor system.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present invention relate generally to bioprocessing systems and methods, and more particularly to bioreactor systems that are capable of selectively changing the shape and / or configuration of single-use culture bags in such systems. [Background technology]

[0002] A variety of vessels, devices, components and unit operations are known for carrying out biochemical and / or biological processes and / or manipulating the liquids and other products of such processes. Increasingly, single-use or disposable bioreactor bags and single-use mixer bags are used as such vessels to avoid the time, expense and difficulty associated with sterilizing vessels used in biopharmaceutical manufacturing processes. For example, biological materials (e.g., animal and plant cells), including mammalian, plant or insect cells and microbial cultures, can be processed using disposable or single-use mixers and bioreactors.

[0003] One type of bioreactor mixing system includes a rigid cylindrical vessel in which a single-use flexible bag is placed. The use of a sterile disposable bag eliminates the time-consuming step of cleaning the vessel and reduces the possibility of contamination. The bag is filled with the desired fluid for mixing, and an impeller (driven by a magnetic drive system or a motor located outside the vessel) located within the bag is used to mix the fluid. Depending on the fluid being processed, the system can include multiple fluid lines and different sensors, probes and ports coupled with the bag for monitoring, analysis, sampling and liquid transfer. For example, a harvest port is usually placed at the bottom of the disposable bag and vessel, allowing a harvest line to be connected to the bag for harvesting and draining the bag after the process is completed.

[0004] The capacity of these single-use flexible bags usually ranges from about 50 liters to about 2,000 liters. In many applications, for example during the initial stages of scale-up, it is desirable to culture at a working volume significantly less than the maximum working volume of the disposable bag. However, system constraints, such as the need to maintain the fluid level in the bag above the area where the sensor penetrates the bag, sometimes make it impossible to work at a volume below a certain lower threshold. This minimum volume at which a given bioreactor system can operate effectively in a controlled manner is called the turn-down ratio. For example, in many large-scale cell culture applications, before a commercial-scale run can be completed in a 2,000 L bioreactor, the process is first run in a small bioreactor to ensure that the cell culture performance is appropriately scaled and can reproducibly achieve the desired cell density, viability, glycosylation pattern, and expression rate. This scale-up process can be very time-consuming and costly, requiring the use of many different bioreactors of increasing capacity. Therefore, the ability to operate bioreactors at low working volumes (high turndown ratios) is desirable because it reduces the number of bioreactors required to scale up to a desired harvest volume. Most bioreactors today have a maximum turndown ratio of 5:1, which means that a 200 L vessel can be effectively operated in a controlled manner down to about 40 L. Summary of the Invention [Problem to be solved by the invention]

[0005] While existing bioreactor systems are generally adequate for what can be considered conventional performance, there is a need for bioreactor systems with increased turndown ratios and improved drainage. [Means for solving the problem]

[0006] In one embodiment, a bioreactor system includes a vessel having a bottom bed, a flexible bioprocessing bag disposed within the vessel, and a flexible bladder disposed intermediate the bottom bed of the vessel and the bioprocessing bag, the flexible bladder being selectively inflatable to change at least one of the shape or configuration of the bioprocessing bag.

[0007] In another embodiment, a method of bioprocessing includes placing a flexible bladder on a bottom bed of a bioreactor vessel, placing a flexible bioprocessing bag in the vessel generally on top of the flexible bladder, performing a bioprocess in the flexible bioprocessing bag, and inflating the flexible bladder to change at least one of the shape or configuration of the flexible bioprocessing bag.

[0008] In yet another embodiment, an apparatus for use in a bioreactor system includes a flexible bladder having an inlet port configured to connect to a supply of pressurized air, the flexible bladder configured to be disposed on the bottom floor of a bioreactor vessel beneath a flexible bioprocessing bag also disposed within the vessel, and configured to selectively expand with the supply of pressurized air to change the shape or configuration of the flexible processing bag to improve drainage or increase the turndown ratio of the bioreactor system.

[0009] The invention will be better understood from reading the following description of non-limiting embodiments, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a front elevation view of a bioreactor system according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a simplified side elevation cross-sectional view of the bioreactor system of FIG. 1 showing the single-use flexible bag and inflatable bladder disposed therein, with the bladder in an uninflated state. [Diagram 3]FIG. 2 is a simplified top plan view of the bioreactor system of FIG. 1 with an inflatable bladder disposed therein. [Figure 4] FIG. 1 illustrates a perspective view of an inflatable bladder, according to one embodiment of the present invention. [Diagram 5] FIG. 2 is a simplified side elevation cross-sectional view of the bioreactor system of FIG. 1 showing the single-use flexible bag and inflatable bladder disposed therein, with the bladder in an inflated state. [Figure 6] FIG. 2 is a top plan view of an inflatable bladder according to one embodiment of the present invention, illustrating the dimensional relationships of the bladder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Reference will now be made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference characters used throughout the drawings refer to the same or like parts.

[0012] As used herein, the terms "flexible" or "foldable" refer to structures or materials that are pliable or can bend without breaking, and can also refer to materials that are compressible or expandable. An example of a flexible structure is a bag made of polyethylene film. The terms "rigid" and "semi-rigid" are used interchangeably herein to describe structures that are "non-foldable", i.e., structures that do not fold, collapse, or otherwise deform under normal forces to substantially reduce their extended dimensions. Depending on the context, "semi-rigid" can also refer to structures that are more flexible than "rigid" elements, such as bendable tubes or conduits, but still do not collapse longitudinally under normal conditions and forces.

[0013] "Vessel", as the term is used herein, refers to a flexible bag, a flexible container, a semi-rigid container, a rigid container, or a flexible or semi-rigid tube, as the case may be. The term "vessel" as used herein is intended to encompass bioreactor vessels having walls or portions of walls that are flexible or semi-rigid single-use flexible bags, as well as other containers or conduits commonly used in biological or biochemical processing, including, for example, cell culture / purification systems, mixing systems, media / buffer preparation systems, and filtration / purification systems, such as chromatography and tangential flow filter systems, and associated flow paths therein. As used herein, the term "bag" refers to, for example, a flexible or semi-rigid container or vessel used as a bioreactor or mixer for the contents therein.

[0014] As used herein, the term "turndown ratio" refers to the breadth of the operating range of a bioreactor and is defined as the ratio of the maximum working volume of the bioreactor to the minimum working volume. For example, a bioreactor with a maximum working volume of 200 liters and a minimum working volume of 40 liters has a turndown ratio of 5:1. As used herein, "drainability" refers to the ability to easily and completely drain the contents of the bioreactor during a batch drain or harvest.

[0015] An embodiment of the invention provides a bioreactor system having a vessel having a bottom bed, a flexible bioprocessing bag disposed within the vessel, and a flexible bladder disposed intermediate the bottom bed of the vessel and the bioprocessing bag, the flexible bladder being selectively inflatable to change at least one of the shape or configuration of the bioprocessing bag to improve drainage or increase turndown ratio for the bioreactor system.

[0016] 1 and 2, a bioreactor system 10 according to one embodiment of the present invention is shown. The bioreactor system 10 includes a generally rigid bioreactor vessel 12 or support structure mounted on top of a base 14 having a plurality of legs 16. The vessel 12 may be formed, for example, from stainless steel, polymers, composites, glass, or other metals and may be cylindrical in shape, although other shapes may be utilized without departing from the broader aspects of the present invention. The vessel 12 may be equipped with a lift assembly 18 that provides support to a single-use flexible bag 20 disposed within the vessel 12. The vessel 12 may include one or more viewing windows 22 that allow for viewing of the fluid level within the flexible bag 20, as well as a window 24 disposed in a lower region of the vessel 12. The window 24 allows access to the interior of the vessel 12 for inserting and positioning various sensors and probes (not shown) within the flexible bag 20, as well as for connecting one or more fluid lines to the flexible bag 20 for adding or withdrawing fluids, gases, and the like from the flexible bag 20. Sensors / probes and controls for monitoring and controlling critical process parameters include, for example, any one or more and combinations of temperature, pressure, pH, dissolved oxygen (DO), dissolved carbon dioxide (pCO2), mixing rate, and gas flow rate. As shown in Figure 1, the vessel 12 can also include a drain port 26 on its bottom surface to which drain tubing can be connected for draining and / or recovering the contents of the flexible bag 20.

[0017] With particular reference to FIG. 2, a schematic side elevation cross-sectional view of the bioreactor system 10 is shown. As shown therein, a single-use flexible bag 20 is disposed within and constrained by the vessel 12. The flexible bag 20 includes an impeller 28 attached to a magnetic hub 30 at the bottom center inside the bag, which rotates on an impeller plate (not shown) also disposed at the bottom inside the bag 20. A magnetic drive 32 external to the vessel 12 provides the motive force for rotating the magnetic hub 30 to mix the contents of the flexible bag 20. Although FIG. 2 illustrates the use of a magnetically driven impeller, other types of impellers and drive systems are possible, including a top-driven impeller. The single-use flexible bag 20 further includes an outlet port 33 configured to align with and be coupled to the discharge port 26, and provide fluid communication therewith for draining the bag 20 after processing, as needed and as desired.

[0018] As shown in Figures 2 and 3, the bioreactor system 10 also includes an inflatable bladder 34 that rests on the bottom surface or floor 36 of the vessel 12 below the flexible bag 20. In particular, the bladder 34 is disposed intermediate the bottom floor 36 of the vessel 12 and the bottom of the flexible bag 20. As shown in Figure 3, the inflatable bladder 34 is generally U-shaped and has a pair of opposing legs 38, 40 that extend generally toward the exhaust port 26 in the vessel 12. An inflation port 42 is provided on one of the legs 38, 40 for selectively inflating and deflating the inflatable bladder 34, as discussed below, although the inflation port may be located elsewhere on the bladder without departing from the broader aspects of the present invention. Figure 4 provides a more detailed view of the inflatable bladder 34. As shown in Figure 4, the inflatable bladder 34 may be in the shape of a segmented torus, having a peripheral shape that generally corresponds to the peripheral shape of the vessel 12 and the bag 20.

[0019] As will be discussed in detail below, the bladder 34 is selectively inflatable and deflatable to change the shape, configuration and volume of the flexible bag 20 (and, in particular, the shape and configuration of the bottom of the flexible bag 20) located on top of the bladder 34. Figure 2 shows the bladder 34 in its deflating state, while Figure 5 shows the bladder 34 in its fully inflated state. In one embodiment, the bladder 34 can be inflated to any intermediate state between the deflating state and the inflated state, as will be discussed below.

[0020] In an embodiment, the single-use flexible bag 20 is formed of a suitable flexible material, such as a homopolymer or copolymer. It can also be formed of a laminate including multiple flexible layers, each such layer can include a homopolymer or copolymer. The flexible material can be USP Class VI certified, such as silicone, polycarbonate, polyethylene, and polypropylene. Non-limiting examples of flexible materials include polymers such as polyethylene (e.g., linear low density polyethylene and very low density polyethylene), polypropylene, polyvinyl chloride, polyvinyl dichloride, polyvinylidene chloride, ethylene vinyl acetate, polycarbonate, polymethacrylate, polyvinyl alcohol, nylon, silicone rubber, other synthetic rubbers and / or plastics. A portion of the flexible container can include a substantially rigid material, such as a rigid polymer, e.g., high density polyethylene, metal, or glass. In one embodiment, the inflatable bladder 34 can be formed of the same or different flexible material as the single-use flexible bag 20.

[0021] FIG. 6 is a top plan view of an exemplary bladder 34 and illustrates various dimensional relationships of the bladder. For example, in a bioreactor having a maximum working volume of about 200 liters, such as a General Electric XDR-200 single-use stirred tank bioreactor having an internal diameter of about 22 inches, and a disposable bag, the bladder 34 can have the configuration shown in FIG. 6, where A is about 4 inches, B is about 15 3 / 4 inches, C is about 19 3 / 4 inches, D is about 5 inches, and E is about 11 1 / 2 inches. Other dimensional relationships and bladder configurations are possible. As discussed in detail below, the inflatable bladder can be sized to enable the bioreactor system to operate with nearly any desired fluid volume. In particular, the volume of the bladder 34 can be selected such that in the inflated state, the level of fluid in the flexible bag 20 is above the point where the sensor penetrates the flexible bag 20. Additionally, the shape of the bladder 34 can be selected to surround but not interfere with the action of the impeller (if either a top-mounted or bottom-mounted impeller is utilized).

[0022] In use, the inflatable bladder 34 can be placed at the bottom of the container 12 prior to inserting the single-use flexible bag into the container 12. The inflation port 42 of the inflatable bladder 34 can then be connected to an instrument air supply through a hose extending through a drain port in the container 12 or through a bottom opening in the container 12 through which the magnetic drive for the impeller extends. In one embodiment, the instrument air can provide 30-90 psi for inflation. The single-use flexible bag 20 is then placed on top of the bladder 34 (in its deflated state), the outlet port 33 on the bag 20 is connected to the exhaust port 26 of the container 12, and the impeller 28 is coupled to the magnetic drive 32 in a manner previously known in the art.

[0023] In one mode of operation, bioprocessing operations are carried out in the bag in a conventional manner. After processing, for example during a harvesting step, or any time the bag needs to be drained, the contents of the bag 20 can be released through the drain port 26. During draining or harvesting, as the fluid level in the bag 20 drops, a supply of instrument air can be used to inflate the bladder 34. As shown in FIG. 5, when the bladder 34 inflates, it lifts the bag 20 upward in the area where it contacts the flexible bag 20. If the bladder 34 is in the shape of a segmented torus, it pushes the bag 20 upward along the bottom, periphery of the bag 20. Inflating the bladder 34 thus changes the configuration and shape of the bottom of the flexible bag 20, creating a funnel-like configuration at the bottom of the bag 20. This serves to facilitate draining of the bag, especially during the final stages of draining, as the funnel-like shape causes the fluid in the bag 20 to flow towards the exit port 33 and the drain port 26. This is in contrast to existing systems in which the flexible bag rests approximately flat on the bottom of the container during the entire drainage process, resulting in less than complete drainage and / or very slow drainage as the fluid level drops.

[0024] In another mode of operation, the inflatable bladder 34 can be utilized to increase and improve the turndown ratio. For example, once the bladder 34 and flexible bag 20 are placed in the vessel 12 in the manner described above, the bladder can be inflated to lift at least a portion of the bag 20 off the bottom of the vessel 12. In one embodiment, process medium can be added to the bag 20 either before or after the inflation of the bladder 34. Inflating the bladder 34 effectively reduces the volume of the bag and increases the fluid level in the bag 20 compared to when the bag 20 is fully located at the bottom of the vessel 12. With the bladder 34 in its inflated state and the process medium in the bag 20, bioprocessing can then be initiated and carried out in a conventional manner. As the process is expanded and the fluid level in the bag increases, the bladder 34 can be deflated (all at once or in stages) so that the maximum working volume of the bag 20 can be utilized. In particular, the bladder 34 can be deflated incrementally (or essentially instantaneously) as its batch is expanded.

[0025] By inflating the bladder 34 during the initial stages of processing, an improved turndown ratio for the bioreactor system can be achieved. For example, a conventional 200 liter bioreactor using a 200 liter disposable bag can have a minimum operating volume of 40 liters, corresponding to a turndown ratio of 5:1. This means that at a minimum operating volume of 40 liters, the fluid level in the bag will be above the sensor, allowing for the desired process control. However, below 40 liters in the bag, the level of fluid in the bag may drop to a point where an accurate sensor reading cannot be obtained (if at all). Thus, in such conventional systems, the process cannot be effectively run at volumes below 40 liters.

[0026] By using the expandable bladder 34 described herein, which can have an internal volume in its expanded state of, for example, 10-15 liters, the minimum operating volume of the bioreactor can be pushed down to about 25-30 liters. In particular, the expansion of the bladder 34 can be used to maintain a minimum fluid level in the bag (e.g., at a level above the sensor) to perform bioprocessing operations at a lower fluid volume than would otherwise be necessary if the bag extended all the way to the bottom of the vessel. For example, in the 200 liter bioreactor described above, if the fluid volume was, for example, 25-30 liters, the fluid level may be below the level required for accurate sensing of process conditions and parameters. However, expansion of the bladder 34 displaces the fluid upward, pushing the fluid level above the level required for accurate sensing, thereby allowing the bioreactor to operate at a lower fluid volume. Thus, in the example given above where expanding the bladder 34 allows the minimum operating volume to be reduced from 40 liters to about 25-30 liters, the turndown ratio of the bioreactor system can be increased to about 6:1 to 8:1, or even more.

[0027] Although the bladder 34 is shown and described herein as having a segmented torus shape, the invention is not so limited in this respect. Indeed, the shape or configuration of the bladder can be selected to provide any desired fluid flow configuration during drainage or retrieval, depending on one or more of the configuration or shape of the flexible bag, the configuration or shape of the vessel and / or its bottom floor, and the location of the drain port and / or impeller / drive component. For example, the bladder 34 can be torus, annular, or wedge-shaped, although other shapes and configurations, such as rectangular, triangular, etc., are also possible without departing from the broader aspects of the invention. In one embodiment, the peripheral shape of the bladder can be selected to correspond to or reflect the internal peripheral shape of the vessel (defined by the internal sidewall). Additionally, the volume of the bladder 34 can be selected to facilitate drainage or increase the turndown ratio to a desired extent, as discussed above.

[0028] Although the inflatable bladder has been shown and described herein for use in a generally cylindrical, flat-bottom bioreactor vessel, various modifications can be made to allow the bladder to be used in bioreactors having other configurations. For example, it is contemplated that the size, shape and configuration of the bladder can be selected to allow the bladder to be used in vessels of any shape (including square, rectangular, etc.), any bottom configuration (flat or funnel shaped), and with any impeller configuration (top-mounted or bottom-mounted).

[0029] In one embodiment, rather than being a separate component that is oriented within the vessel prior to placing the single-use flexible bag 20 within the vessel 12, the bladder 34 can be integrated with the bag 20 itself. For example, the bladder 34 can be welded to the bottom of the bag 20 such that the bag 20 includes two separate chambers, one in the form of an inflatable bladder and the other for holding the process media and performing the bioprocessing operation. An integrated bag and bladder can be utilized in situations where ease of installation is desired, since both the bladder and the processing chamber can be installed in the vessel in a single step. If cost reduction is a primary concern, a separate bladder and bag can be utilized such that the inflatable bladder can be reused after draining and retrieval.

[0030] As discussed above, the flexible bladder of the present invention thus improves drainage for a bioreactor system, as well as allowing for increased turndown ratios of the system by providing the ability to selectively raise the fluid level within the flexible bag to a level above a sensor upon inflation of the bladder. Additionally, the ability to precisely control the levels of inflation and deflation allows for precise control over the manufacturing process to a degree not previously seen in the art.

[0031] In one embodiment, a bioreactor system is provided. The bioreactor system includes a vessel having a bottom bed, a flexible bioprocessing bag disposed within the vessel, and a flexible bladder disposed intermediate the bottom bed of the vessel and the bioprocessing bag. The flexible bladder is selectively inflatable to change at least one of the shape or configuration of the bioprocessing bag. In one embodiment, the vessel includes a drain port in the bed, and the bioprocessing bag includes an outlet port configured to connect with the drain port, the outlet port and the drain port cooperating to facilitate drainage of the contents of the bioprocessing bag. In one embodiment, the bladder is selectively inflatable to raise at least a portion of the bioprocessing bag above the level of the outlet port. In one embodiment, the bladder is selectively inflatable to create a funnel shape at the bottom of the bioprocessing bag to funnel the contents of the bioprocessing bag toward the outlet port. In one embodiment, the bladder has a torus or segmented torus shape in the inflated state. In another embodiment, the bladder has a wedge shape in the inflated state. In one embodiment, the flexible bladder is shaped and positioned to generally surround the drain port in the bottom floor of the vessel. In one embodiment, the bladder is integral with the bioprocessing bag. In one embodiment, the vessel is substantially rigid.

[0032] In another embodiment, a method of bioprocessing is provided. The method includes placing a flexible bladder on a bottom floor of a bioreactor vessel, placing a flexible bioprocessing bag in the vessel generally on top of the flexible bladder, performing a bioprocess in the flexible bioprocessing bag, and inflating the flexible bladder to change at least one of the shape or configuration of the flexible bioprocessing bag. In one embodiment, the method also includes connecting the flexible bladder to a supply of pressurized air. Connecting the flexible bladder to the supply of pressurized air can include inserting a hose from the supply of pressurized air through a drain port in the bottom of the vessel and connecting the hose to an inlet port of the flexible bladder. In one embodiment, inflating the flexible bladder is performed during draining of the flexible bioprocessing bag. In one embodiment, the method also includes placing the flexible bladder at the bottom floor of the vessel to at least partially surround the drain port. In one embodiment, the step of inflating the flexible bladder is performed during a first stage of the bioprocess, and the method can also include a step of deflating the flexible bladder during a second stage of the bioprocess, the second stage occurring in time after the first stage. In one embodiment, the step of inflating the flexible bladder is performed prior to performing a bioprocess in the flexible bioprocessing bag, and the method can also include expanding a culture in the flexible bioprocessing bag, increasing a fluid level in the flexible bioprocessing bag by expanding the culture, and deflating the flexible bladder as the fluid level in the flexible bioprocessing bag increases. In one embodiment, the flexible bladder has one of an annular segmented torus or a wedge shape in the expanded state. In one embodiment, the flexible bladder is integral with the flexible bioprocessing bag.

[0033] In yet another embodiment, an apparatus for use in a bioreactor system is provided. The apparatus includes a flexible bladder having an inlet port configured to connect to a supply of pressurized air. The bladder is configured to be disposed on the bottom floor of a bioreactor vessel, below a flexible bioprocessing bag also disposed within the vessel, and to selectively expand with the supply of pressurized air to change the shape or configuration of the flexible processing bag to improve drainage or increase the turndown ratio of the bioreactor system. In one embodiment, the flexible bladder has one of an annular segmented torus or a wedge shape in an expanded state.

[0034] As used herein, elements or steps defined in the singular and preceded by the word "a" or "an" should be understood not to exclude a plurality of said elements or steps, unless the exclusion of such a plurality is expressly stated. Furthermore, references to "one embodiment" of the invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the specified features. Also, unless expressly stated to the contrary, embodiments "comprising," "including," or "having" an element or elements having a particular characteristic can include additional such elements that do not have that characteristic.

[0035] This written description uses examples to disclose certain embodiments of the invention, including the best mode, and also enables one of ordinary skill in the art to practice the embodiments of the invention, including making and using any devices or systems, and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that differ insubstantial from the literal language of the claims. [Explanation of symbols]

[0036] 10 Bioreactor System 12 containers 14 Base 16 legs 18 Lift Assembly 20 Bags 22 Peephole 24 Windows 26 Discharge port (drainage port) 28 Impeller 30 Magnetic Hub 32 Magnetic Drive 33 Exit Port 34 Vlada 36 Substrate 38 legs 40 legs 42 Inflation port

Claims

1. a vessel (12) having a bottom floor (36); a flexible bioprocessing bag (20) disposed within the vessel (12), the bioprocessing bag (20) including an exit port (33) at a bottom of the bioprocessing bag; a flexible bladder (34) disposed intermediate the bottom bed (36) of the vessel (12) and the bioprocessing bag (20); A bioreactor system (10) comprising: the flexible bladder is selectively inflatable to change at least one of a shape or configuration of the bioprocessing bag, the flexible bladder having a contact surface with the bioprocessing bag when inflated, the contact surface being angled toward the exit port; the bladder is selectively inflatable to create a funnel-like shape at the bottom of the bioprocessing bag to direct the contents of the bioprocessing bag toward the exit port. Bioreactor system.

2. The vessel includes a drain port (26) in the bottom floor (36); the outlet port (33) of the bioprocessing bag is configured to connect with the drain port, the outlet port and the drain port cooperating to facilitate drainage of the contents of the bioprocessing bag; 2. The bioreactor system of claim 1.

3. the bladder is selectively inflatable to raise at least a portion of the bioprocessing bag above the level of the outlet port.

3. The bioreactor system of claim 2.

4. The bladder has a torus or segmented torus shape in an inflated state. A bioreactor system according to any one of claims 1 to 3.

5. The bladder has a wedge shape in an inflated state. A bioreactor system according to any one of claims 1 to 4.

6. the flexible bladder is shaped and positioned to generally surround the drain port in the bottom floor of the container; A bioreactor system according to any one of claims 1 to 5.

7. the bladder being integral with the bioprocessing bag; 7. A bioreactor system according to any one of claims 1 to 6.

8. The container is substantially rigid. A bioreactor system according to any one of claims 1 to 7.

9. placing a flexible bladder (34) on a bottom bed (36) of a bioreactor vessel (12); placing a flexible bioprocessing bag (20) within the bioreactor vessel (12) generally on top of the flexible bladder (34), the bioprocessing bag including an exit port (33) at a bottom of the bioprocessing bag; performing a bioprocess in the flexible bioprocessing bag; inflating the flexible bladder to change at least one of the shape or configuration of the flexible bioprocessing bag, the flexible bladder having a contact surface with the flexible bioprocessing bag when inflated, the contact surface inclined toward the exit port, and the bladder inflates to create a funnel-like shape at a bottom of the bioprocessing bag to inject the contents of the bioprocessing bag toward the exit port; A method of bioprocessing comprising:

10. connecting the flexible bladder to a supply of pressurized air. The bioprocessing method of claim 9, further comprising:

11. the step of inflating the flexible bladder is performed during drainage of the flexible bioprocessing bag. A bioprocessing method according to claim 9 or 10.

12. Positioning the flexible bladder to at least partially surround a drain port (26) in the bottom floor of the bioreactor vessel.

12. The method of bioprocessing according to any one of claims 9 to 11, further comprising:

13. the step of inflating the flexible bladder is performed during a first stage of the bioprocess; The method further comprises the step of contracting the flexible bladder during a second stage of the bioprocess, the second stage occurring in time subsequent to the first stage. A bioprocessing method according to any one of claims 9 to 12.

14. the step of inflating the flexible bladder is performed prior to performing the bioprocess in the flexible bioprocessing bag; The method comprises: expanding a culture in the flexible bioprocessing bag and increasing a fluid level in the flexible bioprocessing bag by expanding the culture; contracting the flexible bladder as the fluid level in the flexible bioprocessing bag increases; Further comprising: A bioprocessing method according to any one of claims 9 to 13.

15. The flexible bladder has one of an annular segmented torus or a wedge shape in an inflated state. A bioprocessing method according to any one of claims 9 to 14.

16. the flexible bladder is integral with the flexible bioprocessing bag; A bioprocessing method according to any one of claims 9 to 15.

17. the step of connecting the flexible bladder to the supply of pressurized air includes inserting a hose from the supply of pressurized air through a drain port at the bottom of the bioreactor vessel and connecting the hose to an inlet port of the flexible bladder.

17. A bioprocessing method according to any one of claims 10 to 16.

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