Mass transfer in aerated culture media combining mixed electrolytes and glucose

The combined effects of mixed electrolyte species and glucose on oxygen transfer were studied in a bubble column with aqueous solutions. Of particular interest was the presence of electrolytes containing ions which are prone to present solute-solute interactions or to crystallize. Without and at low concentration of glucose (≤ 5 g/L), the increasing concentration of electrolytes (nominal ionic strength: 0-0.43 M), up to a critical value, enhanced the volumetric mass transfer coefficient (k_La) and the availability of specific interfacial area (a), due to the inhibition of bubble coalescence. As the glucose concentration increased (10-40 g/L), the enhancing effects of electrolytes were gradually lost. The glucose interacted with electrolytes, reducing their ability to inhibit coalescence and to enhance the k_La. Salt crystallization occurred independently of the addition of glucose; however, it did not have significant effect on mass transfer. Finally, the changes in physicochemical properties were highly collinear with composition variables.