Fermenter is a kind of equipment for microbial fermentation, which is widely used in bioengineering, pharmaceutical, food and beverage production and other fields. It provides a suitable environment for the growth and metabolism of microorganisms, thus enabling the fermentation process.

1. Structure

Fermenter is mainly composed of the following parts:

Tank: This is the main part of the fermenter, usually made of stainless steel, with good sealing and corrosion resistance. A stirring device is designed inside the tank for mixing media and microorganisms to ensure uniformity of conditions such as temperature, pH and dissolved oxygen during the fermentation process.

Ventilation system: It shall be used to deliver the sterile air into the fermenter to meet the demand for oxygen for microbial growth. The ventilation system includes an air filter and a ventilation distributor to ensure even air distribution in the tank.

Stirring system: The medium and microorganisms shall be fully mixed to improve the solubility of oxygen and the utilization of nutrients through the rotation of the agitator. The stirring speed shall be adjusted according to the fermentation needs.

Temperature control system: Precise temperature control is required during fermentation, usually through cooling jackets or heating devices. The cooling jacket allows cooling water to be passed in to reduce the temperature in the tank, while the heating device raises the temperature when needed.

PH control system: Microbial fermentation is very sensitive to PH value, so fermenters shall be equipped with PH electrodes and automatic control systems. The PH is adjusted by adding an acid or base to ensure that the fermentation process is carried out within the appropriate PH range.

Dissolved oxygen monitoring system: It is used to monitor the concentration of dissolved oxygen in the fermentation liquid in real time to ensure that the microorganism obtains enough oxygen. The dissolved oxygen monitoring system is usually linked to the ventilation system and the stirring system to automatically adjust the oxygen supply.

Sampling port: It is used to collect samples of fermentation liquid regularly for the detection and analysis of microbial growth, metabolites, etc.

2. The working principle

The working principle of fermenters is based on the growth and metabolic characteristics of microorganisms. Its workflow mainly includes the following steps:

1. Sterilization: Before the fermentation process, the fermenter and its internal medium need to be strictly sterilized to eliminate the contamination of miscellaneous bacteria. The common sterilization method is through high temperature steam to ensure the sterility of the process.

2. Inoculation: The purified microbial strains shall be inserted into the sterilized fermenter. The inoculation process needs to be carried out under sterile conditions to prevent the mixing of miscellaneous bacteria.

3. Fermentation process: microorganisms grow and metabolize in the fermenter, and maintain suitable fermentation conditions through ventilation and agitation. In the fermentation process, temperature, PH value, dissolved oxygen and other parameters need to be monitored and controlled in real time to optimize the fermentation effect.

4. Product extraction: After fermentation, the required metabolites shall be extracted from the fermentation liquid by centrifugation, filtration and other methods. For some intracellular products, treatment such as cell fragmentation may also be required.