Effect of Solid Carriers on Oxygen Mass Transfer in a Stirred Tank Bioreactor

Various strategies for improving the mass transfer rate of oxygen have been used in order to obtain a good efficiency of aerobic fermentation processes. The paper focuses on studies concerning the influence of solid carrier addition in the liquid phase on oxygen volumetric mass transfer coefficient in a stirred and aerated tank bioreactor. The selected oxygen carriers (vectors) can be easily separated and they have no harmful effect on the microbial population implied in bioprocesses. Fine particle of activated carbon, silicon oil impregnated activated carbon, bacterial cellulose, magnetite, and bacterial cellulose-magnetite composite were used as oxygen-vectors. An enhancement of oxygen transfer was indicated by an increase in volumetric mass transfer coefficient, k l a, which was determined by a dynamic method. A significant improvement of oxygen mass transfer in the presence of magnetite and bacterial cellulose-magnetite composite was highlighted.