Dynamic measurement of KLa with oxygen‐enriched air during fermentation

Abstract A method of KLa estimation, utilising gassing with oxygen‐enriched air, was applied to fermentations of Escherichia coli and Saccharomycopsis lipolytica. The method consists of sudden inlet oxygen concentration increase while total inlet gas flow rate is held constant. Dissolved oxygen concentrations are measured by an oxygen electrode, the response of which is assumed to be first order. KLa can be estimated from the slope of the semilogarithmic plot of the electrode response versus time. The method seems to be valid as long as the dissolved oxygen concentration is higher than the critical oxygen concentration below which oxygen uptake rate is dependent on dissolved oxygen concentration.