Fermentation: Precise gas control for reproducible processes

Definition of fermentation 

In biotechnology, fermentation refers to the conversion of biological materials. It requires the help of biocatalysts such as enzymes or cells and depends on optimum temperature conditions (usually 35 °C to 37 °C).

What plays the important roles in fermentation? 

An optimised fermentation requires precise control of all parameters. The type and concentration of the nutrients, the temperature, oxygen content and pH value are critical. Reproducible processes are fundamental to consistently high product quality. The challenges inherent in this include in particular:

• Having all components comply with applicable approvals.
• Optimising the gas supply control.
• Ensuring that process data is documented and analysable.

Gas supply: Four gases are used in the fermentation process: oxygen O₂, nitrogen N₂, carbon dioxide CO₂ and air. Optimum product growth requires optimum control of these.

Approval: To ensure the quality of the end product, the components used must conform to the applicable approvals.

Flow control

Nutrient solution

Inoculation (as required)

Conventional solution: Rotameters are mechanically-acting floating flow meters, but they do not operate according to the principle of mass or volume flow measurement. They require precise calibration and only work at the pressure and the temperature to which they have been set.

Products

Biological material

35 °C – 37 °C (ideal growth temperature)

Gas extraction

Sampling Product yield

Measuring points

• ORP
• Temperature
• pH
• Pressure
• pO₂

Biocatalysts (cells or enzymes)

Processes that can be traced at any time help keep everything under control. This is the only way to produce consistent quality. Bürkert mass flow controllers (MFCs) help you do this.

Reproducible processes are key

Fermentation processes involving microorganisms – such as bacteria or mammalian cells – play a key role these days in the production of medicines, chemicals, amino acids and much more. 

Decisive for the quality of the end product during fermentation: Precise control of gas quantities. It must match the needs of the ever-increasing cultures. Reproducible processes are the key for precise control:

• Identical processes: Gas dosing data can be retrieved at any time
• Optimum end products: Selectively controlling gases according to the respective process step

Mass flow controller: Precise and repeatable gas control

Be it research laboratory or pilot plant: Bürkert mass flow controllers (MFCs) make the fermentation process reproducible. Since setting of the flow rate can be automated with repeat accuracy. Using just one device, you can control standard fermenter gases such as air, oxygen, nitrogen and carbon dioxide according to the needs of your cultures.

Advantages of Bürkert MFCs:

1. Fermenter gases: Calibrate up to four different gases
2. Approval: Compliant with USP Class VI, FDA and available with 3.1 certificate
3. No fermentation contamination: Parts that come into contact with media are made of stainless steel 
4. Wide setting range: Precise control of ultra-small to large gas quantities thanks to direct- measuring sensors

In contrast to measurements with floats and needle valves, MFCs guarantee identical processes. You also benefit from all the advantages of digitalisation, such as data that can be retrieved at any time. 

Added values for your process 

What is the benefit of precise gas control for your fermentation processes? This is illustrated by the following points:

Flexible integration of MFC solutions

Ethernet, system bus or analogue interface? No matter which communication standard you use, the versatile MFC solutions fit your existing interfaces. We present three integration options below:

Ethernet concept

 
MFCs are connected directly to the higher visualisation level via integrated industrial Ethernet switches.

Bürkert system bus concept

 
MFCs are connected to the Bürkert fieldbus gateway via CANopen-based büS interfaces.

• Suitable for applications with numerous gas flow control loops. 
• Easy start-up: Preconfigured MFC systems are connected to the PLC via a gateway. 
• Permanent access to the device status thanks to digital communication.

Standard signal concept

 
MFCs are connected to the existing I/O system via analogue interfaces.

• Connect MFCs via analogue standard signals and continue to use the existing automation concept.
• You simply adapt the concept to the number of MFCs required.

MFCs and available interfaces:

Industrial Ethernet: PROFINET, EtherNet/IP, EtherCAT, Modbus TCP
Fieldbus: CANopen, RS485/ Modbus as well as PROFIBUS-DP via a gateway
Standard signals: 0/4 … 20 mA, 0 ... 5/10 V (switchable)

One system solution, many advantages

Bürkert also offers modular, customised gas mixing units. We configure these units according to your requirements – using space-saving mass flow controllers arranged side by side, including valves. You receive the units already pre-tested for tightness, pressure and correct electrical operation. The advantages of a complete solution:

✓ You save installation costs
✓ You simplify your engineering tasks
✓ You do not need to order, store and assemble individual parts

Do you want to increase the efficiency of your plant and measure the flow profitably?  Simply contact us for more information.

Mass flow controller (MFC)/mass flow meter (MFM) for gases

Type 8741

• Nominal flow ranges from 0.010 l/min to 160 l/min
• High accuracy and repeatability
• Very fast response times
• Simple device exchange due to configuration memory
• Optional: USP Class VI, FDA, EC 1935 compliant

Mass flow controller (MFC)/mass flow meter (MFM) for gases

Type 8741

• Nominal flow ranges from 0.010 l/min to 160 l/min
• High accuracy and repeatability
• Very fast response times
• Simple device exchange due to configuration memory
• Optional: USP Class VI, FDA, EC 1935 compliant