Biosynthesis of ethyl butyrate using immobilized lipase: a statistical approach

Response surface methodology was used to determine optimum conditions for the esterification of ethanol and butyric acid to produce a flavor ester using immobilized lipase by Candida antarctica. Various reaction parameters including acid and/or alcohol concentration, enzyme concentration, temperature and reaction time affecting the synthesis of ethyl butyrate were investigated. The principal parameters influencing the esterification yield were incubation temperature and substrate concentration. The optimal conditions for the enzymic reaction were obtained at 0.04 M substrate concentration using 7% enzyme concentration at 34 °C for 96 h. Under these conditions the esterification percentage was 72.9%. The kinetics of commercial lipase was also studied and competitive inhibition by ethyl butyrate recorded. The product inhibition constant was 0.16 M.