Biocatalysis and Enzyme Technology Lab, Institute of Food Science and Technology, Federal University of Rio Grande do Sul State, ZC 91501-970, Porto Alegre, Rio Grande do Sul, Brazil.
Biotechnol Prog. 2013 Nov-Dec;29(6):1416-21. doi: 10.1002/btpr.1793. Epub 2013 Sep 30.
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 2(4-1) , 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.
丁酸丁酯是菠萝香精中的一种酯，对食品和饮料工业非常重要。本工作采用固定化脂肪酶 Lipozyme TL-IM 催化合成丁酸丁酯，对反应进行了优化。选择正己烷作为最适宜的溶剂。通过部分因子设计（fractional factorial design），考察了温度、底物摩尔比、生物催化剂含量和添加水量等其他反应参数及其作为产率的响应值，然后采用中心复合设计（central composite design，CCD）和响应面法进行了优化。在 2(4-1)的部分因子设计中，测试了四个变量，结果表明温度和生物催化剂含量具有统计学意义，然后在 CCD 上进行了优化。丁酸丁酯合成的最佳条件为 48°C；底物摩尔比为 3:1（正丁醇：丁酸）；酸质量的 40%的生物催化剂含量。在这些条件下，2 小时内可获得超过 90%的产率。通过用正己烷洗涤生物催化剂或直接重复使用来测试酶的重复使用性。直接重复使用会导致酶活性迅速下降，而用正己烷洗涤则可在保持约 85%的活性的情况下重复使用五次反应循环。
