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Continuous, precisely regulated nutrient supply in a bioreactor
A bioreactor’s purpose is to provide the greatest possible product yield. To do this, it requires precise regulation of all important parameters like nutrient concentration, temperature or oxygen content to optimally support fermentation. Learn how you can use customised valve and sensor solutions for secure, reproducible processes in your fermenters.
Challenges of the fermentation process
Substrates are continuously fed into the bioreactor in a continuous fermentation process, and the yield product is extracted continuously. A closed control loop ensures that the parameters to be regulated always correspond exactly to the specified set-point values as closely as possible. There are a few challenges here:
35 °C – 37 °C (ideal growth temperature)
Biocatalysts (cells or enzymes)
Gas supply: Four gases are used in the fermentation process: oxygen O₂, nitrogen N₂, carbon dioxide CO₂ and air. To ensure optimum product growth, they need to be controlled properly.
Challenges and problems of conventional solutions
The culture system in the fermenter is subjected to constant cell feeding. The biochemical process reacts extremely sensitively to changed parameters. This means that too little or too much nutrient solution must never be added. If the process is disrupted, all supplemented substances are unusable, which results in unnecessary costs and time delays. Diaphragm valves are often used to regulate continuous feeding, although they do not have optimal regulation characteristics.
A: too little nutrient supply; B: correct nutrient supply; C: excessive nutrient supply
For fermentation to function reliably, it is important that production and purification cycles are safely separated from each other. Contamination by foreign germs or CIP media would render the entire batch of the fermented product unusable. In order to avoid unnecessarily high costs, conventional systems often use Coriolis measuring devices to control flow rates, but they are typically heavy and unwieldy, and drive up the pump costs.
Flowmeters, temperature sensors, control valves and other components are often installed in hard-to-reach places in a system or machine. In addition, the devices are usually large and heavy – a conventional flowmeter and a similar valve combined can easily weigh 18 to 20 kilograms. These factors make both installation and subsequent maintenance in everyday production more difficult.
Constant monitoring of the correct glucose feed is intended to secure production processes and guarantee system availability – all with the least possible human effort. At the same time, it serves to comply with the a number of rules and regulations in the pharmaceutical industry, which require complete documentation of the measurement parameters to produce clear traceability. Not all process controls meet this variety of requirements.
Regulating bioreactors safely, quickly and automatically with customised systems
Only when all control loops function perfectly can your machinery ensure efficient production processes and high-quality end products. Valve dimensioning and control loop design are often complex and time-consuming. First, use our valve design tool to get an overview of which valve solution is possible for your fermentation process. We will then be happy to provide you with personal consultation and will compile perfectly selected and dimensioned products for you.
Alternatively, we offer you complete system solutions that reduce your engineering and production process workload – with automation, if you desire. Speak with our experts directly!
Bellows valve including ELEMENT positioner
FLOWave Type 8098
The advantages of the Bürkert system solution:
Unlike conventional solutions, the Bürkert solution provides a local control loop that ensures the direct exchange between the flowmeter and the bellows valve. The valve regulates the amount of nutrient solution to be added based on information from FLOWave. The connected PLC not only monitors the process, but also compares the quantities supplied with the actual requirements of the fermenter, which are calculated from numerous measured values. Conventional solution: Bürkert solution:
Flexible machine concepts with minimal space requirements can be realised with compact Bürkert components. In order to prepare for the challenges of the present and the future, Bürkert also integrates modern digital connectivity into all of its positioner controllers, for example to high-level fieldbuses or an IO-Link. The components can thus be seamlessly integrated into your control systems, which reduces the complexity of the systems in many aspects.
Conventional solution: Bürkert solution:
Conventional solution: DN1/2“: 460 x 177 x 75 mm; valve DN 1/2“: 242 x 327 x 147 mm Bürkert solution: FLOWave (nominal diameter DN 1/2“): (50+92) x 250 x 158 mm; Bürkert valve (nominal diameter DN 1/2“): 65 x (157+38) x 110 mm
Control solutions for fluidic processes by Bürkert are always customised to the specific requirements, such as for fermentation processes. They can be either as perfectly selected and dimensioned, individual products or as complete control loops that reduce customer effort in engineering and manufacturing processes. Such system solutions can typically greatly reduce overall costs compared with purchasing individual components.
Control loop start-up can often be a time-consuming task. But there are ways to speed up the process: The autotune functionality installed in most Bürkert position controllers by default ensures that the regulators are automatically adapted to the system characteristics at the push of a button. The lower weight and compact design of the Bürkert components contribute to quick installation, even in hard-to-reach places.
Conventional solution: Bürkert solution:
Save on installation space and weight
In conventional solutions, the total weight of the two components that control nutrient solution feeds into bioreactors is around 18.5 kg, assuming a DN of ½“ each. By contrast, the total weight of the Bürkert solutions with the same DN is only 4.4 kg. Bürkert’s local control loop can thus save about 14 kg. The solution also requires much less installation space, which results in more flexible system concepts, shorter installation times and lower machine costs.
The Bürkert resistApp helps you identify compatible materials and compiles information for you about the chemical resistance of elastomers, plastics and metals for a large number of gaseous and liquid media.