Fluid Mixing in Fermentation Processes

Abstract

Publisher Summary Mixing is an essential part of fermentation processes. There are two sources of fluid-mixing energy in a fermentation process; mixing impellers provide circulation of fluids through the tank, and the expansion and velocity of air passing through a fermentor imparts fluid motion. This chapter considers the effect of mixing variables on the various process steps in the fermentation. To analyze the effect of mixing on various steps, it is desirable to consider some of the basic components of the fluid regime in the fermentation vessel. Among the essential components of the fluid regime are the power level, impeller pumping capacity, impeller fluid shear rate, fluid shear rate throughout the entire vessel, and superficial gas velocity. Each step in the fermentation process has its own requirement for a mixing fluid regime. One step may be influenced primarily by the power input to the fluid, another step may be influenced primarily by the pumping capacity of the impellers, while another step may be influenced by the fluid shear rate existing in the vessel.