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BACKGROUND: Biochemical oxidation reactions require oxygen to be supplied by dispersed bubbles. Drawbacks of the gas-liquid system are enzyme denaturation and low oxygen utilization efficiency. Therefore, oxygen production through the decomposition of H2O2 is useful for controlled oxygen transfer in bioreactors. %26lt;br%26gt;RESULTS: Catalase-containing liposomes (CALs) were prepared in 50 mmol L-1 Tris/0.1 mol L-1 NaCl buffer (pH 7.4) and the kinetic model was developed for the oxygen production by CAL-catalyzed decomposition of 1.0 mmol L-1 H2O2. Applying the model to the observed time course of oxygen produced gave overall resistance in the reaction based on the pseudo-steady-state assumption inside liposomes for H2O2 and oxygen. The reaction resistance was estimated with the liposomal catalase concentration e(t,in) and the kinetic parameters of free enzyme reaction. At e(t,in) = 0.59 mu mol L-1, the CAL reaction proceeded under reaction control, while at e(t,in) = 5.05 mu mol L-1, the H2O2 transfer resistance was involved. For the latter case, the permeability coefficient P-P of H2O2 through the liposome membrane was determined as 1.06 x 10(-6) m s(-1) at 25 degrees C. The model predicted the H2O2 concentration inside liposomes with different e(t,in) values. Furthermore, the oxygen concentration in the CAL dispersions was reasonably simulated. The oxygen production rate could be altered based on temperature (10-55 degrees C) and the fractional volume of CALs. %26lt;br%26gt;CONCLUSION: The CAL-catalyzed oxygen production was controlled based on the e(t,in) and P-P values, which determine the relative importance of the reaction and H2O2 transfer resistances. The CAL would be applied to oxidation reactions instead of gas-liquid systems.
- 出版日期2014-9
