Bubble Diameter, Mass Transfer, and Bioreaction of Dynamic Membrane-Stirred Reactors

The gas-liquid mass transfer of reactors is the focus of intensifying biochemical engineering. Hence, this paper develops a dynamic membrane-stirred reactor to increase the gas-liquid mass transfer efficiency (k_La) and improve bioreactions. Dynamic membrane coupling mixing and aeration form uniform microbubbles to intensify gas-liquid mass transfer. The optimal pore diameter and blade angle of the dynamic membrane are 10 μm and 45°, respectively, providing more uniform microbubbles, better gas-liquid mixing performance, higher gas holdup, and better k_La. Compared with the traditional stirred reactor, the dynamic membrane-stirred reactor reduces the energy consumption by 50% and improves biomass and enzyme activity. The maximum dry cell weight is 30.13 g·L^-1, and the maximum specific cell growth rate is 0.38 h^-1, 48.9% higher and 31% higher than the traditional reactor. To sum up, the unique structure of a dynamic membrane-stirred reactor effectively reduces the bubble diameter and improves k_La and the bioreaction process.