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Temperature Control for Laboratory and Industrial Fermentation

This article looks at the fermentation process and how it is used with genetic engineering to solve problems, address disease, and enhance the human experience. It looks at the applied science of fermentation and how temperature affects results within the process. There is a look into how fermentation scientists can improve workflows and outcomes by using temperature control equipment with specific features and functionalities.

The History and Culture of Fermentation

Humans have used fermentation to improve their lives from the beginning of civilisation. It turned sour milk to cheese, allowing people to preserve camel and goat milk supplies. In today’s society, fermentation plays a big role in many industries such as medical, pharmaceutical, food, and much more.

Most of us are familiar with products that depend on the fermentation process, items such as sourdough bread, wine, beer, vinegar, soy sauce, miso, kimchi, kombucha, and pickled vegetables. However, biotechnology also uses fermentation to produce pharmaceutical drugs, enzymes, vitamins, nutraceuticals, insulin, bioplastics, etc. There are even uses for the byproducts of the fermentation process; for example, carbon dioxide, a byproduct of beer fermentation, can be used to create a range of products, including dry ice. The applications and uses for fermentation are wide and varied in many industries, spoken about below.

Fermentation in Industry

Pharma, biopharma and medical

Biological fermentation has been vital in developing vaccines and antibody treatments, most recently used to address the COVID-19 pandemic.

Food and beverage

In addition to many fermented foods and beverages, fermentation can produce food flavour additives, thickeners, and preservatives. Genetic engineers are even using modified yeast to add the aroma of hops to a non-alcoholic beer to enhance the consumer experience.

Cosmetics, fragrances and personal care

Cosmetic companies use microbial fermentation to produce biomelanin, an ingredient that protects against sun damage. Many amino acids, peptides, hyaluronic acids, and active ingredients in cosmetics and skincare depend on fermentation.

Bioremediation and environmental science

Currently, fermentation is being used to explore ways to clean microplastics from the oceans and address chemical spills.

Agriculture and food waste

Using microbial fermentation, microbes are cultivated to produce biofertilizers and biopesticides to maintain crop health. Fermentation scientists are also looking into using food waste as fuel for spaceships.

Chemicals and Alternative biofuels

Fermentation converts carbohydrates (such as starch or sugar) into an alcohol or acid. These alcohols, such as ethanol, can be used as solvents or an alternative to fossil fuels.

Wastewater management

Wastewater treatment centres have been using methane fermentation for years to reduce sewage sludge’s mass and volatile content.

So, what exactly is fermentation?

Fermentation is a metabolic process that uses an organism (bacteria, yeast, or filamentous fungi) to convert a carbohydrate into a simpler compound, typically an acid or alcohol. The process uses the microorganism (bacteria, yeasts, and filamentous fungi) to metabolise substrates (carbon sources of various kinds such as glucose, starch, cellulose, and other polymers) as fuel for metabolism.

In intracellular reactions, these carbon sources are broken down, creating:

Adenosine 5′-triphosphate or ATP, the dominant energy carrier
Primary metabolic products (CO2, ethanol, acetic acid, or similar molecules)
Secondary metabolites
Or just more cell material (biomass)

Both the primary metabolites (ethanol, lactic acid, and certain amino acids) and the secondary metabolites are beneficial in many products and applications. Secondary metabolites include terpenes, flavonoids, penicillin, and more. These secondary metabolites add colour, flavour, and other characteristics to the fermented product.

What conditions are necessary for fermentation?

Fermentation, in general, happens without oxygen under anaerobic conditions, meaning it occurs in the absence of oxygen. This process evolved millions of years ago when the atmosphere contained little to no oxygen.

Later as photosynthesis generated more oxygen, the microorganisms used respiration as a more energy-efficient way to create biomass and propagate.

For fermentation to occur, the microorganisms (yeast, bacteria, or filamentous fungi) need a carbon source, phosphor, nitrogen, other nutrients, water, a controlled atmosphere, and a suitable temperature for the bacteria or fungi to multiply efficiently. Learn more about the laborator temperature regulators that can help maintain these conditions.

Temperature Control for Fermentation

For fermentation, precise control of multiple parameters is needed to manufacture the desired product repeatedly. The PRESTO Temperature Control Systems are ideal for such demanding applications. These parameters include sterility, and various unit operations such as atmosphere, reagent, and/or feedstock addition, agitation, and temperature. Fermentation produces heat as a byproduct that can raise the temperature above the desired range. The re-circulating cooler-chillers can effectively remove this excess hear, ensuring high yields and reproducibility. This can cause the production of unwanted byproducts and reduce the yield of the desired product. Temperature control is key to high-yielding and reproducible fermentations.

How to Select a Temperature Control Unit for Fermentation Applications?

Fermenters that have jacketed external walls or internal coils often use a circulating temperature control unit that can control the process temperature. The DYNEO DD heating circulator baths provide the appropriate heating/cooling capabilities for these demanding applications. Most fermentations occur in the range of 20°C to 85°C, with exceptions (such as lager beer fermentation). Temperature control units with the appropriate heating/cooling capabilities provide the proper temperature conditions for fermentation and allow you to remove heat from the process, ensuring high yields and batch-to-batch reproducibility.

The size of fermenters varies greatly from bench-scale (less than 5L) to production scale. Several factors determine which unit you will need for your application, including the size of your fermentation vessel and its heating and cooling capacities.

Consider these when determining the size of the temperature control unit:

Size of the fermentation vessel
Desired process temperature range
Fermentation process volume
Required time to temperature, if applicable
Required heating/cooling capacity (if known)
Heat output of the fermentation process (if known)
The fluid volume of the vessel jacket or coil assembly

Automation and Communication Interfaces

Most manufacturers use some form of automation to control the fermenter and control unit operations. Having automation means there is no chance for human error, increases precision, and greatly improves batch-to-batch reproducibility.

It is important to look for a unit that integrates with a programmable logic controller to streamline the fermentation temperature control. You’ll also want to consider the I/O (input/output) interface to the PLC. I/O options include analog (voltage or current), RS232/RS485, Ethernet, USB, Modbus, Profibus, or Ethercat communication portals.

If the fermenter does not have remote temperature monitoring, then a temperature control unit that includes an external temperature control function (such as Pt100 or thermocouple) will be beneficial. Adding a PT100 or thermocouple will allow you to control and monitor conditions inside the process.

JULABO Temperature Control Solutions for Fermentation

For smaller fermentation setups using benchtop to 20L vessels, JULABO offers the DYNEO DD and MAGIO MS series refrigerated/heating circulators. These units feature heaters ranging from 1kW to 2kW and cooling capacities up to 1kW. Connectivity options include USB, with additional choices of analog or RS232 for the DYNEO DD, and USB, Ethernet, RS232/RS385, Modbus, and an analog option for the MAGIO MS series.

For general cooling needs, the FL chiller product line supports fermenters with cooling power ranging from 0.3kW to 20kW. These chillers also provide RS232 communication, and heaters can be added to achieve temperatures up to +95°C.

Larger fermentation vessels (over 20L) are ideally paired with the SemiChill and PRESTO series. The SemiChill chillers offer cooling power from 2.5kW to 10kW, with options to include heaters and various I/O capabilities. The PRESTO series, suitable for even larger setups, features single-stage units with cooling capacities from 0.5kW to 25kW and heating from 2.3kW to 27kW, utilizing glycol/water mixtures for efficient heat transfer. PRESTO units also support a broad range of communication options including USB, Ethernet, RS232, Modbus, and additional options for analog, Profibus, and Ethercat.

Conclusion

Fermentation drives many innovations and solutions from its advantages over other chemical and industrial processes. It consumes less energy than other processes, produces less waste, generates fuels, and is often the safest process. With more and more genetic engineering and research into how organic organisms such as bacteria, fungi, and yeast can be used, we expect to see growing demands for fermentation temperature control.

For an expert opinion on what temperature control unit suits your processes, please contact our team today.

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