Lipase-catalyzed synthesis of isoamyl acetate in free-solvent media — optimization using a central composite design

Author: Gabriela A. Macedo ^*, Gláucia M. Pastore and Maria I. Rodrigues

Received 23 October 2002, accepted 16 May 2003.

Abstract

The catalytic action of two non commercial lipases (E.C. 3.1.1.3) in the synthesis of isoamyl acetate in a solvent-free system, were tested using an experimental design in order to better understand the relationship between the reaction variables. Yields ranging from 67 to 77 % molar conversion were achieved. The synthesis of isoamyl acetate catalyzed by the chosen lipase (Rhizopus sp.) was optimized, in order to maximize the molar conversion (yield, Y) in a solvent-free system. Response surface methodology involving the substrate molar ratio (RM) and amount of lipase (L) was used, and a second order model was employed to generate response surfaces. The optimum conditions to obtain Y max = 80% were: RM= (2:1); L= 8.7% ( w/w), 40°C, and 48 hours of reaction time.