This Demonstration shows the influence of gassing rate
and stirrer speed
on an enzymatic aerated reactor. The transfer coefficient
is a function of
The solubility of oxygen in aqueous solutions at ambient temperature and pressure is only between 8 and 10 ppm. This amount of oxygen is quickly consumed in aerobic cultures and must be constantly replaced by sparging (bubbling air through the liquid) .
: substrate concentration (g/L)
: product concentration (g/L)
: dissolved oxygen concentration (mg/L)
: saturation dissolved oxygen concentration (mg/L)
: critical dissolved oxygen concentration (mg/L)
: substrate uptake rate (g/L h)
The transfer coefficient
The model that includes reaction kinetics and mass balances is described in .
 P. M. Doran,
Bioprocess Engineering Principles
, Boston: Elsevier, 1995.
 I. J. Dunn, E. Heinzle, J. Ingham and J. E. Přenosil,
Biological Reaction Engineering
, 2nd ed., Weinheim, Germany: VCH Verlagsgesellschaft mbH, 2003.