Optimization of Synthesis of Ethyl Isovalerate Using Rhizomucor miehei Lipase

—Immobilized lipase from
Rhizomucor miehei
(Lipozyme IM-20) was used to catalyze the esterification
reaction between isovaleric acid and ethanol to synthesize ethyl isovalerate in
n
-hexane. Response surface methodology
based on a four-variable, five-level, central composite rotatable design was employed to optimize four
important reaction variables—enzyme/substrate (E/S) ratio, substrate concentration, incubation time, and temperature—
affecting the synthesis of ethyl isovalerate. The optimum conditions predicted for achieving maximum
ester yield (500 mM) are as follows: E/S ratio, 48.41 g/mol; substrate concentration, 1 M; reaction time, 60 h; and
temperature, 60°
C. The predicted value matched well with the experimentally obtained value of 487 mM.