Stainless steel fermentation tanks create the controlled environment required for microorganisms or cells to grow and for enzymes to catalyze biochemical reactions. Tank configurations vary according to the process: solid-state or liquid fermentation, aerobic or anaerobic operation, mechanical or airlift agitation, and single-stage or multi-stage culture expansion before production fermentation.

The culture medium enters the tank first, and the agitator keeps it moving throughout fermentation. As the liquid circulates, nutrients and heat spread more evenly through the culture. Aerobic processes (which require oxygen for microbial growth) also receive sterile-filtered compressed air through a bottom air distributor, while the agitator disperses the air as bubbles to improve oxygen transfer. The control system monitors temperature, pressure, pH, and liquid level throughout the process and adjusts the agitator speed or air flow when necessary. Once the fermentation cycle is complete, the fermented product leaves the tank through a sterile discharge route.