Most food fermentation relies on the metabolism of aerobic microorganisms (such as yeast, acetic acid bacteria, and some lactic acid bacteria), so continuous oxygen is needed to promote their growth and reproduction and product synthesis. This process is called aerobic fermentation.

As the core power equipment of the oxygen supply system for aerobic fermentation, air compressors not only provide gas, but also ensure efficient oxygen transfer, sterile safety, and adaptation to microbial metabolic needs through oil-free, deep purification, and dynamic regulation. Therefore, they directly affect the efficiency and stability of fermentation.

Air compressors are involved in many key links of "air preparation-transportation-oxygen supply-system maintenance" in aerobic fermentation, and the specific process is as follows:

(1) Inhale Air and Compress

The air compressor draws in ambient air and mechanically compresses it to achieve the required pressure range for fermentation. This process powers subsequent air delivery and purification, while high-pressure air more effectively overcomes pipeline resistance and the static pressure of the fermentation broth, ensuring smooth oxygen supply into the fermentation system.

(2) Transport Compressed Air

The compressed air is transported through the pipeline system to the fermentation tank, with the air compressor serving as the core power source for this process. During transportation, the compressor's pressure must overcome pipeline resistance, liquid column pressure within the fermentation tank, and system leakage to ensure stable delivery of air to the fermentation tank.

(3) Purify the Compressed Air

The air used for fermentation must undergo strict purification to remove impurities such as bacteria, dust, moisture, and oil to prevent contamination. Compressed air is pressurized and sequentially passes through a pre-filter, cooler, and precision filter to ultimately obtain "sterile compressed air".

(4) Aeration and Oxygen Supply in the Fermenter

The purified sterile compressed air is introduced into the fermentation broth through an air distributor at the bottom of the fermenter, creating aeration and oxygen supply. Under pressure, the compressed air disperses into microbubbles that fully contact the liquid. Oxygen dissolves from these bubbles into the liquid to support microbial respiration and metabolic processes. The air compressor's flow rate and pressure directly determine bubble dispersion and oxygen transfer efficiency. Dissolved oxygen serves as a critical limiting factor for aerobic microorganisms' metabolic activities.

(5) Maintain the Pressure in the Fermenter

During fermentation, the fermenter requires maintaining a specific internal pressure. The air compressor continuously supplies compressed air to help stabilize this pressure. The positive pressure inside the tank reduces risks of external bacteria entering through pipeline joints or valve gaps. Maintaining appropriate pressure also enhances oxygen solubility in the fermentation broth, thereby improving oxygen supply efficiency.

(6) Purging and Cleaning of Auxiliary Equipment

When the fermentation batch is over, the compressed air provided by the air compressor can be used to blow away the residual material or moisture in the fermenter, pipeline, filter, and other equipment, so as to prepare for the subsequent cleaning or sterilization, and avoid the contamination of residual substances in the next batch of fermentation.

In conclusion, the cleanliness of compressed air in food fermentation is extremely high, and it is necessary to avoid contaminating food or affecting microbial activity, so it should meet the following requirements:

(1) Oil-Free

In the process of food fermentation, the cleanliness of compressed air is extremely high, and oil-free air compressors, such as oil-free screw machines, must be used to avoid lubricating oil contamination of food or inhibition of microorganisms.

(2) Cleanliness

Compressed air needs to be filtered through multiple stages to remove moisture, dust, and microorganisms to meet food-grade standards. This requires air compressors to be equipped with efficient filtration systems to ensure that the output compressed air meets food production safety standards.

(3) Stability

Flow and pressure should be controlled according to process requirements to avoid fluctuations affecting fermentation efficiency. Air compressors should have good regulation performance, which can accurately control air flow and pressure according to actual needs during the fermentation process to ensure a stable fermentation process.

Ingersoll Rand's LS Series low-pressure oil-free screw air compressors deliver an ideal compressed air solution for the food fermentation industry through their oil-free cleanliness, high efficiency, stability, and intelligent energy-saving features. This series of compressors meets all stringent requirements during fermentation processes, ensuring safe, efficient, and stable operation throughout the production cycle.