Lipozyme TL IM was used to catalyse the esterification of isoamyl alcohol and butyric acid. A fractional factorial design was employed to evaluate the effects of temperature (30, 40, 50 °C), alcohol:acid molar ratio (1:1, 2:1, 3:1), enzyme concentration (0.003, 0.0115, 0.020 g mL-1), butyric acid concentration (0.1, 0.3, 0.5 mol L-1) and shaking rate (50, 115, 180 rpm) on the ester yield. With these results, the levels were redefined to a 2³ factorial design. The maximum yield of ester was obtained at 30 ºC, 180 rpm, alcohol:acid molar ratio of 1:1, enzyme concentration of 0.021 g mL-1 and butyric acid concentration of 0.5 mol L-1. Under the optimal conditions, 92% esterification was attained with an ester concentration of 0.9 mol L-1. Isoamyl alcohol from fusel oil was used under the same conditions and resulted in 93% esterification and an ester concentration of 1.0 mol L-1.
flavor ester; Lipozyme TL-IM; organic media; response surface methodology (RSM); fusel oil
