What is fermentation? Know more about this chemical process

It is closely linked to organisms such as bacteria and yeast, although lactic fermentation also exists in the animal's muscle tissue.

What happens in the fermentation process? During this transformation within the molecules, there is an incomplete oxidation process, resulting in energy generation. From this perspective, fermentation is less efficient in ATP or Adenosine production since it only produces 2 molecules of this compound, while aerobic cellular respiration can produce 38.

Types of fermentation

There are different types of fermentation, with specific characteristics, in the next paragraphs, you will learn more about.

• Alcoholic fermentation: Occurs during the processing of alcoholic beverages, such as beer or wine, although it's not only for that industry. In this case, it is carried out with yeast and converts glucose, fructose, and sucrose into ethanol and carbon dioxide (CO2) producing a reduced ATP.
• Lactic fermentation: This type of fermentation aims to produce lactic and acetic acid by yeast grains. Lactic acid bacteria (LAB) are more active since they provide outstanding flavor, pleasant aromas have a greater participation since they provide properties such as an outstanding flavor, pleasant aromas and textures that characterized good bread.
• Acetic fermentation: A category that involves a redox type of reaction, that is; instead of producing oxidation, it’s an electron transfer by the action of bacteria, primary alcohols (Molecules with two hydrogens that lose one to become an aldehyde) and acetic acids.
• Malolactic fermentation: Fermentation that is carried out mainly with fruits can be linked to some wines since it contains a large amount of malic acid. It is colloquially known as “second fermentation” because this is when the wine takes on its mildest flavor and should occur naturally in a blend. For this reason, the aging time is so important in the red wine aging process.
• Propionic fermentation: Produced by a bacterium called Propionibacterium genus, and we see it much more frequently in the dairy sector, specifically in cheese production. In it, compounds such as acetic acid, carbon dioxide and succinic acid are involved. Combining these two elements, we obtain a corrosive substance: propionic acid.
• Butyric fermentation: Type of fermentation with which butyric acid is obtained from glucose in an oxygen-free environment. It has the characteristic of giving off unpleasant odors. Even so, there are other compounds that come to have an attractive smell and flavor, giving rise to various flavorings.

Fermentation history

People have used fermentation for thousands of years without even realizing it is used or how it occurs. Until recently, it was thought that Turkey’s oldest bread was made. However, there is existing evidence for more than 14 000 years. As we know, bread requires yeast to have that spongy effect that many consumers prefer. Therefore, fermentation is as old as the recipe we know today, even more.

Another product derived from fermentation is beer, and, according to some data its origin is possible in 3500 BC in Egypt, where wine was reserved only for the highest classes.

But it wasn’t until Louis Pasteur discovered how fermentation operates in 1822, we could understand the entire process. This is the story; as a request from a wine producer, the researcher was asked why the wines were so acidic or bitter after a certain time.

The results obtained showed that this effect was entirely due to lactic acid and alcohol produced from fermentation. In other words, with this discovery, it was found that microorganisms under conditions such as heat and closed environments give this feature to beverages.

What is industrial fermentation?

Fermentation is a naturally occurring process and for industrial microbiology, it’s a key to food and beverage production. Industrial microbiology is the field concerned with microorganisms that can be used in processing. In these cases, knowing the tools and technology we can use to handle them without damage is extremely important.

Biochemistry, biology, and mechanics are needed to know what environmental conditions or temperatures suit microorganisms. Other equipments involved in these processes are bioreactors, in which microorganisms' cultures are generated for fermentation. That’s the base of fermentation science.

Currently, there are equipment and components available to carry out the industrial fermentation process, which could be adapted or customized according to the final product expectations. Specialist recommendations are about the type of fermentation to be carried out, since acid production or the use of microorganisms is a decisive factor.

At Autmix Flow, we have a vast variety of equipment made for the fermentation process. Find out in our catalog the ideal solution.

The agitation mechanism must provide a homogeneous movement through the tank so that the microorganism can grow successfully. In the case of the safety required for the products, equipment with mechanical seals is recommended to prevent the access of unwanted agents, and finally, for uniform dispersion and distribution, impellers that help the movement throughout the tank without leaving residues.

Turbines, impellers, or profiles are important components in any mixing process because they determine the direction of the fluid and can be divided into axial or radial.

Now, we recommend some ideal equipment and components to make the process possible:

• Rushton turbine: A radial flow turbine with a flat disc and four to six vertical blades, maintaining constant pressure inside the tank. An ideal impeller option for dispersion and fermentation.
• Inter RT(N) Series: Equipment that can mix a wide variety of liquids, and is compatible with a vast impeller variety, including Rushton type.

In the short answer, we already know that fermentation requires an oxidant, but the characteristics of this process also require agitation equipment that includes quality mixtures.

Although it is not the only characteristic to take care of since the mechanical reactions that occur inside a fermentor tank add heat to the system, it must be dispersion and controlled with a system that regulates speed and power.

Let’s review one of the most interesting processes, beer fermentation or brewing.

• Malting: Barley seed germination stage, in which it is determined whether a beer will be dark or light, as well as its category, although it's too early to tell.
• Maceration: Mixing the previously obtained malt with water in different phases and proportions, depending on the beer brand and its flavors.
• Filtration: Separation of the mixture from the malt. The liquid now has valuable elements for the fermentation stage.
• Boiling: Applying heat is required to add secondary ingredients to the beer mix. This is where other components, such as coffee or sweeter flavors, like fruit, can be integrated.
• Fermentation: The main topic, which consists of different stages starting with glycolysis to become alcohol. Remember that later, the mixture will be left to rest as required.
• Ripening and cooling: Once the product is ready, the cooling stage starts for 5- and 30-day periods, at –1 to 4°C temperatures. It is now that another physical-chemical process begins microorganism sedimentation. At this moment, the beer starts to clarify since the separation between liquid and solid is evident, and a second filtration is necessary, before the next phase.
• Bottling: According to the specifications of the final product, the bottling starts through lines designed to achieve this task. The best containers are selected carefully to preserve the drinks' quality. Many producers add carbonation to this phase just before pouring the liquid.

However, the main topic is fermentation, and it is important for various industrial sectors. We’ll discuss the stages involved and how we can help you achieve high-quality results.

• Lag Phase (LAG): The yeast or microorganism is added, depending on the fermentation type, and an industrial agitator is used to stimulate the growth. For example, if we need heat transfer or an ideal gas dispersion, such as oxygen, an agitator can help us to achieve a successful task. Subsequently, rest is applied from 12 to 25 hours, depending on the expected results.
• Exponential Growth Phase: Also known as logarithmic, microorganisms reproduce rapidly, due to the abundance of glucose, fructose, and sucrose. This doubling interval occurs cumulatively, and bacterial growth requires careful monitoring.
• Stationary Phase: The microorganism population has stopped, reaching its maximum admissible value, and stagnate in population. The speed of fermentation, little by little, is more constant due to the nutrients decrease, corresponding to the maturation phase.
• Death Phase: Fermentation ends when there is no more foam or bubbles, and the microorganisms have already separated, so the mixture begins to clear. This stage needs filtration equipment to support the previous flocculation and obtain purer substances.

Other examples of fermentation

We have seen that alcoholic beverages are not the only fermentation examples. There are so many products made by fermentation, these are some of them:

• Yoghurt: Fermented milk-based food.
• Bread: Food made from flour, water, and salt.
• Cheese: Solid food based on fermented milk.
• Vinegar: acetic acid solution with a concentration from 3 to 5 percent.
• Soy sauce: Food product made by seed fermentation.
• Coffee: Drink that is prepared with roasted beans and heat.
• Vitamins: Compounds derived from fermented cabbage chard, or cabbage, such as vitamin C, which is complex to formulate correctly, or K2, a form of fermented soybeans.
• Antibiotics: As is the case with penicillin, which is obtained from fungi fermentation from the Penicillium genus or the Streptomyces bacterium.

The importance of the fermentation process in the industry

Thanks to fermentation as a catabolic oxidation reaction, it is possible to obtain different products, not just food and drinks. Certain antibiotics or medicines are made from fermentation, so innovation in equipment and technology is crucial. Are you looking for solutions that will help you with your projects? At Autmix, we have a wide agitator catalog, components, and accessories to carry out your projects with great efficiency. Contact us!