Synthesis of (Z)‐3‐hexen‐1‐yl butyrate in hexane and solvent‐free medium using Mucor miehei and Candida antarctica lipases

Abstract

Z)-3-Hexen-1-yl butyrate is an important flavor and fragrance compound as it represents the model of a natural herbaceous (green) note. Two immobilized lipases from Mucor miehei (Lipozym IM) and from Candida antarctica (Novozym 435) were investigated for their use in the synthesis of (Z)-3-hexen-1-yl butyrate by direct esterification in n-hexane. To determine optimal conditions for esterification, we examined the following parameters: temperature, amount of lipase, acid/alcohol ratio, and absence of solvent. In n-hexane, bioconversion yields reached 95 (after 4 h) and 92% (after 6 h) for, respectively, Lipozym IM [17 (w/w reactants)] and Novozym 435 [2% (w/w reactants)]. In the absence of solvent, at 60°C, Novozym 435-catalyzed esterification afforded the title compound in 80% yield. Up to 250 g (in hexane) and 160 g (without solvent) of ester were easily prepared, in a single operation, at a laboratory scale, in few hours, using 2% (w/w reactants) lipase.Low-molecular-weight esters derived from short-chain carboxylic acids (acetates, propionates, butyrates, …) represent an important class of flavoring materials. They are responsible for the fruity odors of many foods and fragrances (1,2). In foodstuff industries, flavor and fragrance loss due to various reasons including manufacturing processes must be compensated for by the addition of aromas. Moreover, there is a growing demand for natural flavors containing green notes represented by C-6 alcohols derivatives. Hence, the biological production of such esters is of much current commercial interest. In this context, the use of immobilized lipases working in nonaqueous media (3-14) has potential since esters produced from natural acids and alcohols may be considered as natural. This mode of production is of great interest, as it would make food industry less dependent on seasonal, climatic, and geographical variations.The present work deals with the biosynthesis of (Z)-3-hexen-1-yl butyrate as a model compound catalyzed by two commercial immobilized lipases from Mucor miehei and from Candida antarctica. Our purpose was to determine best experimental conditions and procedure to produce rather large amounts of C 6 alcohol-derived esters (150 to 250 g), at a laboratory scale, in a single operation as an intermediate step to pilot scale, our ultimate goal being the industrial production from natural acids and alcohols of esters considered to be natural (15)(16)(17). The impact of several parameters on the bioreaction was carefully investigated and optimized, i.e., the nature and the amount of enzyme, the substrate concentration, the temperature, and the acid/alcohol ratio. We also investigated C. antarctica-catalyzed synthesis of the title compound in the absence of solvent. MATERIALS AND METHODS Materials.Lipases from M. miehei immobilized on macroporous anion exchange resin Lipozym IM [5-6 Batch Acidolysis Units NOVO (BAUN)·g −1 , cloned into Aspergillus oryzae] and C. antarctica immobilized on acrylic resin Novozym 435 [7000 Propyl Laurate Units (PLU)·g −1 , cloned...

A robust methodology for kinetic model parameter estimation for biocatalytic reactions

“…The biocatalysis of ( Z )‐3‐hexen‐1‐yl butyrate by direct esterification was successfully achieved using lipases in n ‐hexane and in a solvent‐free system in a previous report 3. In our study the molar conversion of hexyl butyrate by direct esterification in n ‐hexane was higher than that in the solvent‐free system under the same reaction conditions.…”

“…Carvalho et al 2 reported that hexyl acetate was synthesised by the cutinase‐catalysed transesterification reaction of butyl acetate with hexanol in a reversed micelle system. Bourg‐Garros et al 3 synthesised ( Z )‐3‐hexen‐1‐yl butyrate in high yield by direct esterification using Mucor miehei (Lipozyme IM) and Candida antarctica (Novozym 435) lipases in hexane and in a solvent‐free system.…”

Solvent-Free Synthesis of Flavour Esters through Immobilized Lipase Mediated Transesterification

“…Majumder et al [25] obtained a 100% molar conversion in case of benzyl acetate synthesis in 10 min using Lipozyme RM IM lipase and vinyl acetate as an acyl donor. In another study Bourg-Garros et al [26] reported 80% bioconversion yield of (Z)-3-hexen-1-yl butyrate in 4 and 6 h using M. miehi and C. antarctica lipases, respectively, under solvent-free conditions.…”

Lipase‐catalysed biosynthesis of hexyl butyrate by direct esterification: optimisation by response surface methodology

“…3 In our study the molar conversion of hexyl butyrate by direct esterification in n-hexane was higher than that in the solvent-free system under the same reaction conditions. Owing to its low toxicity and easy removal after the reaction, n-hexane was chosen as organic solvent in the optimal synthesis of hexyl butyrate by RSM.…”