Optimization of flavor ester synthesis catalysed by Aspergillus niger lipase

The performance of Aspergillus niger lipase in catalyzing of butyl butyrate synthesis was studied as a function of reaction parameters temperature (°C), substrate molar ratio and added water (% (v/v)). A face-centered design (FCD) and response surface methodology (RSM) were applied in order to optimize the esterification yield (Y). The optimal conditions for butyl butyrate synthesis were found at 40°C, substrate molar ratio of 1:2.41 butyric acid:n-butanol and added water content of 1.05% (v/v). Under these conditions, over 94.5% of esterification was obtained in 20 h. It was verified a favorable effect of alcohol excess in relation to acid. High temperatures (above 40°C) were detrimental to the synthesis of butyl butyrate. Addition of water also provided a strong increase in esterification yield (%).This high esterification yield represents an improvement to previously reported results and confirms the potential application of Aspergillus niger lipases (ANL) in processes for producing flavor ester.