DEPENDENCE OF GAS-LIQUID MASS-TRANSFER ON STRUCTURE AND HYDRODYNAMICSOF BIOREACTORS WITH LOW-DENSITY BIOPARTICLES

Draft-tube fluidized-bed bioreactors for oxygen consuming bioprocesses catalyzed by immobilized cells have been developed. The characteristi cs of the reactors concerning the intensity of gas-liquid oxygen trans fer were investigated by different methods. It was established that th e change of volumetric oxygen transfer coefficient and a dimensionless number corresponding to it are in strong correlation with the dissipa ted power in the reactor. The effect of low density particles modellin g cell support on the oxygen transfer was much smaller than it is gene ral in traditional three-phase reactors. It was concluded that the spe cial structural and hydrodynamical properties of the new reactor types can counterbalance the well-known bubble coalescing effect of biocata lyst particles.