Long-term continuous synthesis of aspartame precursor in a column reactor with an immobilized thermolysin.
N-(Benzyloxycarbonyl)-L-asparty-L-phenylalanine methyl ester, the precursor of the synthetic sweetener aspartame, was continuously synthesized in an immobilized thermolysin plug-flow type reactor at 25 degrees C with the substrates (N-benzyloxycarbonyl-L-aspartic acid and L-phenylalanine methyl ester) dissolved in ethyl acetate. The immobilized enzyme was quite stable in ethyl acetate containing 2.5% 0.01 M 2-(N-morpholino)ethanesulphonic acid-NaOH buffer, pH 6.0, and 20 mM CaCl2 with or without the substrate at 25 degrees C. By periodically washing the column, we could conduct a continuous reaction for over 500 h with an average yield of 95% and a space velocity of 1.85 h-1.
Department of Food Science and Technology, Kyoto University, Japan.
K
K
Nakanishi
A
A
Takeuchi
R
R
Matsuno
D001218:Aspartame; D001407:Bacillus / Q000201:enzymology; D001426:Bacterial Proteins / Q000378:metabolism*; D004151:Dipeptides / Q000138:chemical synthesis*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D013820:Thermolysin / Q000378:metabolism*
D001426:Bacterial Proteins; D004151:Dipeptides; D004800:Enzymes, Immobilized; C051210:N-benzyloxycarbonyl-aspartylphenylalanine methyl ester; D013820:Thermolysin; D001218:Aspartame