Designing Agitated Aerobic Bioreactors for Low Shear

Excessive shear rates within a bioreactor can damage the microorganisms within. This article describes the calculations and best practices for reducing shear rates inside these vessels.

Though bioreactors have been used by humanity for centuries in the form of anaerobic processes to produce alcoholic spirits, the use of aerobic bioreactors really started in the 20th century with the advent of penicillin. Since then, aerobic processes have grown by leaps and bounds, creating products as varied as antibiotics, enzymes, amino acids, alternative proteins, and monomers for biopolymer production. Along with the proliferation of products, an increasing variety of microorganisms — and even plant and animal tissues — have been processed in bioreactors. Some of these materials are fragile and can be damaged by too much shearing in the process vessel. This article explores ways of minimizing shear in agitated aerobic bioreactors...