NOVEL DIRECT SYNTHESIS OF L-PHENYLALANINE METHYL-ESTER BY USING RHODOTORULA-GLUTINIS PHENYLALANINE AMMONIA-LYASE IN AN ORGANIC-AQUEOUS BIPHASIC SYSTEM

A procedure for the direct, one-step enzymatic conversion of trans-cinnamyl methyl ester to L-phenylalanine methyl ester is described. The reverse reaction of phenylalanine ammonia lyase from Rhodotorula glutinis was utilized for this conversion. Insolubility of substrate trans-cinnamyl methyl ester in aqueous buffer solution was overcome by employing an organic-aqueous biphasic system, heptane:0.1 M Tris-sulfate buffer, pH 9.0 (2:1). Different conditions were optimized for the maximal conversion arch as time (16-18 h), temperature (30 degrees C), pH (9.0), concentration of substrates, 0.1 M trans-cinnamyl methyl ester and 1 M (NH4)(2) SO4, and nature of the organic solvent (heptane); about 70% conversion of substrate to product was obtained under these conditions. Formation of the product, L-phenylalanine methyl ester, was identified by paper chromatography and was further confirmed by autoradiography and NMR spectral analyses.