The characteristics of yeast strains and their applications in the biological fermentation industry, as well as the requirements for fermentation tanks

I. Characteristics of Yeast Strains

Yeast is a microorganism widely used in the processes of food, beverages and biological fermentation, especially playing an important role in the fermentation of alcoholic beverages, the production of baker's yeast and the production of biofuels. Yeast belongs to the category of fungi. The most common species of yeast is Saccharomyces cerevisiae. In addition, there are also species such as Candida and Kluyveromyces.

• Morphological characteristics: Yeast is generally a single-celled fungus, oval or round in shape, with relatively large cells, and it divides in a budding manner. Yeast has strong adaptability and can grow under various environmental conditions, such as different temperatures, pH values and oxygen concentrations.
• Physiological characteristics: Yeast conducts respiration under aerobic conditions, consuming oxygen to generate energy. In an oxygen-deficient or anaerobic environment, it will obtain energy through fermentation and produce alcohol and carbon dioxide. This characteristic of yeast has been widely applied in industrial fermentation processes, especially in the production of alcohol and carbon dioxide.
• Metabolic characteristics: Yeast can utilize various sugars as carbon sources, such as glucose, sucrose, fructose, etc., to ferment and produce ethanol or other by-products. Different yeasts vary in sugar utilization efficiency and the types of products they generate. Therefore, in industrial production, different yeast strains are often selected as needed.
• Tolerance: The tolerance of yeast is one of the important factors for its wide application. It has a strong ability to withstand high temperatures, acids and alkalis, and alcohol. During the industrial fermentation process, yeast often needs to grow under rather harsh conditions, such as high concentrations of alcohol and acidic environments.

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II. Application of Yeast in the Biological Fermentation Industry

Yeast is widely used in the biological fermentation industry, especially in fields such as food, beverages, energy and chemicals, playing a crucial role.

• Alcoholic fermentation: Alcoholic fermentation is one of the most traditional and widely used applications of yeast. Yeast can convert sugars into ethanol and carbon dioxide. This process is at the core of winemaking, brewing beer, making wine and other fermented beverages. By selecting different yeast strains, factors such as the fermentation speed, temperature and alcohol concentration can be controlled, thereby optimizing the alcohol production process.
• Bread fermentation: The application of yeast in bread production is also very common. Yeast ferments the dough, generating carbon dioxide gas, which causes the dough to expand and form a soft structure. In addition to Saccharomyces cerevisiae, other yeast species such as Saccharomyces exiguus are also used to improve the texture and flavor of bread.
• The production of biofuels: Yeast plays an important role in the production of biofuels. By fermenting the sugars in agricultural waste, yeast can produce ethanol, which makes it possible to replace traditional petroleum energy. Nowadays, bioethanol has become an important renewable energy source and is widely used in automotive fuel.
• The production of organic acids and enzymes: Yeast is not only used in alcohol production but also can ferment to produce organic acids, such as lactic acid and citric acid. In addition, yeast can also be used to produce various enzymes, such as transglycoase and protease, which are widely applied in the fields of food, feed, medicine and chemical engineering.
• In the field of medicine, the genetic engineering modification technology of yeast has made its application in the biomedical field increasingly widespread. Yeast is used as an expression system to produce recombinant proteins, vaccines and other drug components. For example, yeast can produce insulin, hepatitis B vaccine, etc. during the fermentation process.
• Wastewater treatment: The application of yeast in wastewater treatment has also gradually attracted attention. Yeast can absorb certain harmful substances in water or degrade toxic chemicals, and has the potential to treat water pollution.

III. Requirements for Fermentation Tanks

Fermentation tanks are indispensable equipment in biological fermentation production. The growth and metabolic activities of yeast directly depend on the environmental control of the fermentation tank. Therefore, the design and operation of the fermentation tank are of vital importance to ensuring the smooth progress of the fermentation process. The following are some basic requirements for the fermentation tank.

• Temperature control: The growth and fermentation activity of yeast are significantly affected by temperature. The optimal growth temperature for most yeasts is between 25℃ and 35℃. Both excessively high and low temperatures can inhibit the activity of yeast and even lead to its death. Therefore, the fermentation tank must be equipped with a good temperature control system to ensure the stability and suitability of the temperature during the fermentation process.
• pH control: Yeast is highly sensitive to changes in pH value, and different yeasts have different pH adaptation ranges. Generally speaking, the optimal pH value for yeast is between 4.5 and 6.5. Exceeding this range may affect the activity of yeast and even lead to the failure of fermentation. Therefore, a pH adjustment system needs to be equipped in the fermentation tank to regulate the pH value in real time during the fermentation process and ensure the most suitable growth environment for yeast.
• Dissolved oxygen control: Yeast cells proliferate under aerobic conditions and undergo fermentation under anaerobic conditions. Dissolved oxygen content has a direct impact on the growth of yeast and its metabolic pathways. In the early stage of fermentation, yeast requires sufficient oxygen for the growth and reproduction of cells. In the later stage of fermentation, yeast turns to anaerobic fermentation and produces alcohol and carbon dioxide. Therefore, the fermentation tank needs to have an effective gas input and stirring system to ensure good dissolved oxygen conditions.
• Stirring and mixing: The stirring system in the fermentation tank plays a significant role in maintaining the uniformity of the culture medium and promoting the growth and metabolism of yeast. Reasonable stirring can increase the contact between yeast and the culture medium, optimize the supply of dissolved oxygen, and contribute to the emission of carbon dioxide. The stirring speed needs to be adjusted according to the specific requirements of fermentation. Stirring too fast or too slow will affect the growth of yeast.
• Material and hygiene requirements for fermentation tanks: As the growth of yeast requires strict aseptic conditions, the material of the fermentation tank must have good corrosion resistance and be easy to clean. The commonly used stainless steel material is an ideal choice, featuring high-temperature resistance, acid and alkali resistance, and ease of cleaning. The fermentation tank should be capable of withstanding high temperatures and pressures, and at the same time be able to discharge the gases produced by fermentation without polluting the environment.
• Automation and Monitoring System: Modern fermenters are usually equipped with an automation control system that can monitor parameters such as temperature, pH value, dissolved oxygen concentration, and stirring speed in real time. Through automated control, all indicators during the fermentation process can be maintained in the best condition, ensuring the maximum activity of yeast and the efficiency of fermentation. Such systems can also optimize the production process and enhance production efficiency and product quality through data collection and analysis.

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Iv. Summary

Yeast, as an important microorganism, is widely used in the biological fermentation industry. From alcohol fermentation to bread fermentation, and then to applications in biofuels and the medical field, the advantages and potential of yeast have been widely recognized. To ensure the smooth progress of the fermentation process, the design and use of the fermentation tank are of vital importance and must meet multiple requirements such as temperature, pH, and dissolved oxygen. With the development of technology, modern fermentation tanks have tended to be intelligent and automated, capable of achieving precise control, thereby further enhancing the efficiency of the fermentation process and product quality.

On the other hand, when choosing a bioreactor fermenter, it is necessary to find a regular manufacturer with good reputation and strength, so as to ensure the quality of the product. Jiangsu Mike Biotechnology Co., Ltd. was established in 2008, is a focus on biological fermentation equipment research and development, production and sales of high-tech enterprises. Our company has a pilot fermentation platform, which is integrated with intelligence and automation, and has built a mature fermentation system, which can realize the optimization of pilot fermentation process, commissioning development of all process processes from pilot fermentation production to fermentation product separation and purification, and set up a doctor workstation and a modern laboratory.

Our company has a standardized production plant, with complete sets of equipment and tools required for installation, mainly including a variety of machine tools, automatic argon arc welding machine, automatic polishing machine, automatic cutting machine and flaw detection machine and other more than 60 sets of production and testing equipment, the production process all realize modern standard operation, to provide customers with more professional quality and technical support.