PERFORMANCE OF PERSTRACTIVE ENZYME REACTOR FOR SYNTHESIS OF ASPARTAMEPRECURSOR

A perstractive enzyme reactor was used for the synthesis of N-(benzylo xycarbonyl)-L-aspartyl-L-phenylalanine methyl ester (ZAPM), the precur sor of the artificial sweetener, aspartame. The synthesis of ZAPM in t he reactor proceeded by an enzymatic reaction between N-(benzyloxycarb onyl)-L-aspartic acid (ZA) and L-phenylalanine methyl ester (PM) in th e aqueous phase. The synthesized ZAPM in the aqueous phase was mainly extracted into the organic phase, therefore, the concentration of ZAPM in the aqueous phase could be kept low. As a result, high conversion of ZAPM was obtained with this system. The partition coefficients of s ubstances in the aqueous/butyl acetate biphasic system, the mass trans fer coefficients of substances through the membrane and the enzymatic kinetics of ZAPM synthesis were determined experimentally. The reactio n model which was based on the material mass balance equations was dis cussed to estimate the performance of the perstractive enzyme reactor system. The calculation values using the model and the experimental da ta showed good agreement with the concentration changes of the substan ces in the system.