Optimized butyl butyrate synthesis catalyzed by thermomyces lanuginosus lipase

Butyl butyrate is an ester present in pineapple flavor, which is very important for the food and beverages industries. In this work, the optimization of the reaction of butyl butyrate synthesis catalyzed by the immobilized lipase Lipozyme TL-IM was performed. n-Hexane was selected as the most appropriate solvent. Other reaction parameters such as temperature, substrate molar ratio, biocatalyst content and added water, and their responses measured as yield, were evaluated using a fractional factorial design, followed by a central composite design (CCD) and response surface methodology. In the fractional design 24-1, the four variables were tested and temperature and biocatalyst content were statistically significant and then used for optimization on CCD. The optimal conditions for butyl butyrate synthesis were found to be 48°C; substrate molar ratio 3:1 (butanol:butyric acid); biocatalyst content of 40% of acid mass. Under these conditions, over 90% of yield was obtained in 2 h. Enzyme reuse was tested by washing the biocatalyst with n-hexane or by direct reuse. The direct reuse produced a rapid decrease on enzyme activity, while washing with n-hexane allowed reusing the enzyme for five reactions cycles keeping approximately 85% of its activity. © 2013 American Institute of Chemical Engineers.This work was supported by grants from Fundação de Amparo a Pesquisa do Rio Grande do Sul (FAPERGS–ARD/2011) from CNPq (Brazilian Bureau of Science and Technology), and CTQ2009‐07568 from Spanish Ministerio de Ciencia e Innovación. The authors would like to thank Mr. Ramiro Martínez (Novozymes, Spain) for kindly supplying the enzymes used in this research. They also thank Ministerio de Ciencia e Innovación by a fellowship for C. Garcia‐Galan and CNPq–Brazil for a fellowship to J. L. R. Friedrich and FAPERGS–Brazil for a fellowship to A. B. Martins.Peer Reviewe