title: Synthesis of aspartame precursor with an immobilized thermolysin in mixed organic solvents.
abstract: N-(benzyloxycarbonyl)-L-aspartyl-L-phenylalanine methyl ester, a precursor of the synthetic sweetener, aspartame, was synthesized from N-(benzyloxycarbonyl)-L-aspartic acid and L-phenylalanine methyl ester with an immobilized thermolysin (EC 3.4.24.4) in the mixed organic solvent system of tert-amyl alcohol and ethyl acetate. A mixed solvent consisting of tert-amyl alcohol and ethyl acetate at a ratio of 33:67 (v/v) was found to be the most suitable with respect to synthetic rate and stability of the immobilized enzyme. The reaction continued to proceed quite successfully in a column reactor at 40 degrees C and at a space velocity of 3.6 h(-1) with a yield of 99%, using 40 mM Z-Asp and 200 mM PheOMe dissolved in the mixed solvent as the substrate. (c) 1995 John Wiley & Sons, Inc.
authors.affiliation: Department of Biotechbology, Faculty of Engineering, Okayama University, Tsushima-naka, Okayama 700, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Miyanaga
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Sakiyama
authors.forename: K
authors.initials: K
authors.lastname: Nakanishi