Enzymatic synthesis optimization of isoamyl butyrate from fusel oil

Abstract

Many food, cosmetic and pharmaceutical industries have increased their interest in short-chain esters due to their flavor properties. From the industrial standpoint, enzyme reactions are the most economical strategy to reach green products with neither toxicity nor damage to human health. Isoamyl butyrate (pear flavor) was synthesized by isoamyl alcohol (a byproduct of alcohol production) and butyric acid with the use of the immobilized lipase Lipozyme TL IM and hexane as solvents. Reaction variables (temperature, butyric acid concentration, isoamyl alcohol:butyric acid molar ratio and enzyme concentration) were investigated in ester conversion (%), concentration (mol L-1) and productivity (mmol ester g-1 mixture . h), by applying a sequential strategy of the Fractional Factorial Design (FFD) and the Central Composite Rotatable Design (CCRD). High isoamyl butyrate conversion of 95.8% was achieved at 24 hours. At 3 hours, the highest isoamyl butyrate concentration (1.64 mol L-1) and productivity (0.19 mmol ester g-1 mixture . h) were obtained under different reaction conditions. Due to high specificity and selectivity of lipases, process parameters of this study and their interaction with the Lipozyme TL IM are fundamental to understand and optimize the system so as to achieve maximum yield to scale up. Results show that fusel oil may be recycled by the green chemistry process proposed by this study.

Fusel Oil: Chemical Composition and an Overview of Its Potential Application

“…Regarding the carboxylic (fatty) acid to alcohol molar ratio, shown in Table 2 as R, it is observed that, in most of the works reported, the synthesis of esters is favored with the increase of both reagent amounts. In some researches the increase was only in the FO amount 36,47,48,53 and in others only in carboxylic acid quantity. 14,15,43,49 In most cases, the increase in the reactants concentration tends to positively influence the reaction, shifting it to increased product formation.…”

“…4.50%). 34,53 Octanoic acid, known as caprylic acid, has presented antimicrobial activity on several microorganisms, including: Escherichia coli, Salmonella enterica, Staphylococcus aureus and Listeria monocytogenes. 101 3,7,11-Trimethyl-2,6,10-dodecatrienol, a terpene known as farnesol, has shown potential as an antimicrobial agent 27 and is used in agricultural crops as mite parapheromones.…”