Synthesis of ethyl isovalerate using Rhizomucor miehei lipase: optimization.

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 five-level four-variable central composite rotatable design was employed to optimize four important reaction variables such as 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; temperature, 60 degrees C. The predicted value matched well with experimentally obtained value of 487 mM.