Mass transfer properties of bubble columns suspending immobilized glucose oxidase gel beads for gluconic acid production

The volumetric gas-liquid oxygen transfer coefficient, k(L)a, and the liquid-solid coefficient, k(S), were measured in a 6.7 L external loop airlift bubble column (ELBC), a 2.5 L internal loop airlift (ILBC) and a 2.5 L normal bubble column (NBC) by the steady state method proposed previously using the oxidation of glucose with air catalyzed by glucose oxidase, GO. For an improved and simultaneous determination of k(L)a and k(S), GO was entrapped in calcium alginate gel beads together with fine palladium particles instead of catalase to decompose the hydrogen peroxide produced. The gas holdup, epsilon(G) in each type of bubble column and the liquid circulation velocity, u(L), governing epsilon(G) in the ELBC were also measured to correlate the data on k(L)a according to the previous correlations proposed for a larger scale of the ELBC, ILBC and NBC. The data on k(L)a, k(S), epsilon(G) and u(L) (only for the ELBC) in the reaction system were compared to each other for the three types of bubble columns. The results are well predicted by the previous correlations.