Development of the Simulated Moving-Bed Reactor Equipped with Membrane-Type Enzyme Reactors

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The objective of this study is to develop a new process by combining the enzyme reactors and simulated moving-bed adsorber and to achieve the high-yield production of lactosucrose (4^G-beta-D-galactosyl sucrose).By carrying out the batch reaction experiments using the enzyme solution, it was found that the transfructosylation followed the ordered bi bi mechanism and the hydrolyses of sucrose and lactosucrose took place simultaneously. The reaction rates were formulated from the obtained reaction mechanism. The reaction experiments using the enzyme immobilized on resin particles as well as the enzyme trapped in the hollow-fiber ultrafiltration membrane were also carried out. By immobilizing the enzyme on the resin, the lactosucrose selectivity was reduced, In the follow-fiber membrane reactor, the mixing conditions reached complete mixing, which slightly reduced the lactosucrose selectivity.The adsorption isotherms and volumetric mass transfer coefficients of each saccharide were determined in single-column breakthrough experiments.Simultaneous reaction and separation experiments were carried out by using the simulated moving-bed reactor with enzyme solution as well as with immobilized enzyme. The selectivity and yield of lactosucrose were 71% and 51% respectively when the enzyme solution was used at 50。C.The lactosucrose selectivity was 60% when the immobilized enzyme was used at 50。C.The results of the numerical simulation of the simulated moving-bed reactor demonstrated that the reverse reaction of the transfructosylation is successfully suppressed by applying the simulated moving-bed technology to this reaction system. It was also found that the sucrose conversion in each reaction column has to be reduced and the number of the reaction columns has to be increased in order to obtain a high yield of lactosucrose in the simulated moving-bed reactor equipped with the immobilized enzyme columns.