Brief description of the form, advantages and disadvantages of fermentation tanks in the fermentation process

**Main Operation Modes of Fermentation Tanks**

Industrial fermentation is categorized into three main operation modes based on the fermentation process:

1. **Batch Fermentation**:

- This is the most common industrial fermentation method, also referred to as batch fermentation.

- After sterilizing the fermentation tank and culture medium, seeds are inoculated, and the fermentation process begins.

- This method is simple to operate, less prone to contamination, and requires low investment. However, it has low production capacity, high labor intensity, and inconsistent product quality.

2. **Continuous Fermentation**:

- In this mode, fresh culture medium is added to the fermentation tank at a constant rate, while an equivalent amount of medium is discharged, maintaining a steady liquid volume.

- This allows microorganisms to grow in a stable state and enables long-term continuous operation.

- Continuous fermentation offers high production capacity but demands precise control, higher investment, and is susceptible to contamination and microbial strain variation.

- It is primarily used in laboratory research on fermentation kinetics and occasionally in industrial fermentation for strains with stable genetic properties, such as alcohol fermentation.

3. **Fed-Batch Fermentation**:

- This method combines aspects of batch and continuous fermentation. It is commonly used in industrial applications.

- Nutrients or precursors are added to the fermentation tank at specific intervals during the fermentation process, while the volume in the tank increases until it reaches the maximum operating capacity.

- **Single Fed-Batch Fermentation**: A basal culture medium is initially added, and nutrients are continuously supplied until the fermentation broth reaches the maximum volume, at which point it is discharged.

- **Repeated Fed-Batch Fermentation**: A portion of the fermentation broth is periodically discharged to maintain the volume within the fermenter's capacity, allowing for extended fermentation cycles until yields decline significantly.

- Fed-batch fermentation mitigates issues like nutrient inhibition, product feedback inhibition, and glucose degradation. It also prevents excessive cell growth and oxygen consumption in aerobic fermentation caused by excessive sugar addition, ensuring better ventilation and agitation.

- This method is widely applied in producing single-cell proteins, amino acids, growth hormones, antibiotics, vitamins, enzymes, nucleotides, organic acids, and other fermentation products.

Fed-batch fermentation effectively balances the advantages of batch and continuous fermentation while addressing their limitations, making it a versatile and widely used technique in the fermentation industry.