Optimization of Lipase Catalyzed Synthesis of Nonyl Caprylate using Response Surface Methodology (RSM)

Abstract

Nonyl caprylate, a citrus and rose flavor is short-chain ester with fruity notes is widely used in food, cosmetic and pharmaceutical industries. Traditionally, flavor esters are produced by chemical method or extracted from natural sources. However, with the steadily growing demand for natural flavor compounds, the biosynthesis of such esters by lipase under mild conditions has been receiving much attention for producing these valuable products. In this study, enzymatic synthesis of nonyl caprylate in solvent free system, was successfully optimized via Response Surface Method (RSM) based on 5-level, 4-variable of Central Composite RotaTable Design (CCRD). The parameters were reaction time (3-8 hours); reaction temperature (30-50°C); amount of enzyme (10-20 %, w/w) and shaking speed (100-200 rpm). The optimum condition derived via RSM for the reaction was reaction time of 6.6 hours, reaction temperature of 30.08ºC, enzyme amount of 20 % (w/w) and shaking speed of 128.7 rpm. The actual experimental yield was 90.91% under the optimum condition, which compared well with the maximum predicted value of 91.33%. Comparison of predicted and experimental values reveals good correspondence between them, implying that empirical models derived from RSM can be used to adequately describe the relationship between the factors and response in the synthesis of Nonyl Caprylate.