Optimized enzymatic synthesis of methyl benzoate in organic medium. Operating conditions and impact of different factors on kinetics
Enzyme-catalyzed synthesis of methyl benzoate is reported. It is the first example of direct esterification of benzoic acid which provides good yields. The reaction was performed in a heterogeneous medium by Candida rugosa lipase powder suspended in a hexane/toluene mixture. The impact of some factors was examined. Benzoic acid does not inhibit the lipase until 100 mM. Above 90 mM, methanol inhibits the enzyme. This inhibition is partially eliminated by increasing benzoic acid concentration. Below 90 mM, methanol mainly interacts with the water adsorbed on the biocatalyst. A minimum water content is necessary to activate the biocatalyst. Water must be provided proportionally to the lipase content. Toluene, necessary for benzoic acid solubilization, also acts negatively on reaction kinetics. This is attributed to a modification of benzoic acid partition between the biocatalytic and the organic phases. Copyright 1998 John Wiley & Sons, Inc.
Leszczak
JP
Ecole Nationale Superieure des Mines de Saint-Etienne, Centre SPIN, Laboratoire de Genie Enzymatique, 158 Cours Fauriel, 42023 Saint-Etienne, France.
Tran-Minh
C