An important aspect of industrial microbiology is the transfer of a
process from small-scale laboratory equipment to large-scale commercial
equipment, a process called scale-up. An understanding of scale-up is important because industrial processes rarely behave
the same way in large-scale fermentors as in small-scale laboratory
equipment (Figure 15.3). Many scale-up challenges arise from
problems with aeration and mixing. Oxygen transfer is much more
difficult to achieve in large fermentors than in small fermentors
because the rich culture media used in industrial fermentations
support high cell densities, and this leads to high oxygen demand.
If oxygen levels become limiting, even for a short period, the culture
may reduce—or even shut down—product formation.