The characterization of the oxygen transfer capabilities of fermentors

A method of characterizing the oxygen mass transfer capabilities of fermentors was developed where volumetric oxygen mass transfer coefficients are obtained using a modified sulfite oxidation method in conjunction with on line digital data processing. Carboxymethylcellulose is used in the reaction media to simulate the viscosity of typical non-Newtonian fermentation broths. Using this method, instantaneous values of volumetric oxygen mass transfer coefficients can be obtained for various combinations of agitation and airflow rates in different fermentor configurations. This data is useful in the scale up or scale down of fermentors. Data obtained using this method have revealed that for a given fermentor configuration, oxygen transfer capability decreases with increasing medium viscosity up to some critical value, after which further increases in viscosity produce little change in oxygen transfer. Such data were obtained quickly and easily by this method thus demonstrating its usefulness as a tool in characterizing and comparing fermentor oxygen mass transfer capabilities. Accuracy of the data obtained is limited by the accuracy of the sensing devices and control instrumentation employed