Simultaneous measurements of oxygen diffusion coefficients and solubilities in fermentation media with polarographic oxygen electrodes

Abstract

A membrane-covered oxygen electrode was used to measure oxygen diffusion coefficients and solubilities in aqueous glucose solutions and various fermentation media following a newly developed methodology. The fermentation media studied were tryptic soy broth and those for fermentations of Penicillium chrysogenum, Saccharomyces cerevisiae, and Micrococcus glutamicus. The experimental results of oxygen diffusion coefficients and solubilities in glucose solutions were in good accord with the literature data. As for the fermentation media, both oxygen diffusion coefficients and solubilities were found to decrease with an increased fractional composition of these media, and log-additive behaviors of the oxygen diffusion coefficients and solubilities in fermentation media were observed.

Oxygen mass transfer in a stirred tank bioreactor using different impeller configurations for environmental purposes

“…When the sparger is located under the stirrer, it has been shown that sparger type does not significantly affect mass transfer. Also Oosterhuis et al has noted that correlations related to K L a in stirred bioreactors do not depend on the sparger or stirrer design [26]. …”

Theoretical modelling of the effect of surface active species on the mass transfer rates in bubble column reactors

“…Thus, for concentrations of CaCl 2 that are below the critical concentration that reduces drastically the coalescence, a partially mobile drainage model for bubble coalescence is implemented, Eq. (20). Another important consideration is the fact that bubble velocity gets reduced due to the presence of this species surrounding the bubbles.…”

“…Since the addition of CaCl 2 did not modify the viscosity of the solution [20,100] for the range of salt concentrations used in this work, [CaCl 2 ] < 0.5 M, diffusivity was assumed to be…”

“…According to that work, liquid viscosity attenuates the concentration gradients surrounding the bubbles by means of absorbing bubble oscillations reducing "k L ". Bubbles are 1385 [17,19,20] and different types of surfactants/alcohols are also often produced [18,23]. Salts together with surfactants affect bubble surface properties.…”

“…. [17][18][19][20][21], etc., providing a wide range of physical properties to the liquid phase which affect not only the mechanisms of the physical processes involving bubbles, namely bubble formation, coalescence and break-up, but also the mass transfer rates.…”