Lipase catalyzed transesterification of ethyl butyrate synthesis in n-hexane— a kinetic study

Abstract

Kinetics of lipase catalyzed transesterification of ethyl caprate and butyric acid was investigated. The objective of this work was to propose a reaction mechanism and develop a rate equation for the synthesis of ethyl butyrate by transesterification using surfactant coated lipase from . The reaction rate could be described in terms of Michaelis-Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both the substrates. The values of kinetic parameters computed were V = 2.861 μmol/min/mg; K = 0.0746 M; K = 0.125 M; K acid = 0.450 M. This study indicated a competitive enzyme inhibition by butyric acid during lipase catalyzed transesterification reaction. Experimental observations had clearly indicated that the substrates as well as product act as dead-end inhibitors.

The occurrence, enzymatic production, and application of ethyl butanoate, an important flavor constituent

“…Therefore, ethyl butanoate can be produced from the reaction of ethyl pentanoate or ethyl decanoate and butanoic acid by acidolysis. 8 This reaction is mostly used for the production of structured triacylglycerol. [63][64][65][66] Interesterification reaction is a reaction between two esters where both of the esters interchange the acid-derived R group and turn into two new esters.…”

“…91,92 The nature of reaction medium or solvent affects the enzymatic reaction by causing activation, inactivation, and inhibition as solvent always interacts directly with the enzymes, substrates, or products. 8,93 Enzymatic reaction system can be divided into several types. The basic types include the water-based reaction system, organic solvent-based reaction system, biphasic reaction system, and solvent-free reaction system.…”

“…On the other hand, water-immiscible (hydrophobic) solvents (log P value higher than 2) do not affect the aqueous layer around the enzyme, thereby keeping the enzyme active. 8,98,106 Several studies on ethyl butanoate production in different organic solvents with different log P values were found. Three organic solvents, n-hexane (log P value 3.5), n-heptane (log P value 4.0), and isooctane (log P value 4.1) were studied where it was found that as the log P value was quite similar to each other, all of them showed a similar yield of ethyl butanoate.…”

“…But only three studies have been found where water-based reaction system was applied. 56,57,99 Each of the biphasic and solvent-free systems was studied only once in the ethyl butanoate production, 8,113 whereas in one study, the biphasic system was used in the esterification reaction to study the substrate concentration, different organic solvents as organic phase, the water content in the aqueous phase, temperature preference, and immobilized enzyme stability. 113 In another study, the transesterification of butanoic acid and ethyl caprate in a solvent-free system and an organic system was studied.…”

Screening of organic solvents for bioprocesses using aqueous-organic two-phase systems

“…On the other hand, essentially water-immiscible organic solvents (containing only small amounts of water, at concentrations less than saturation) like n-hexane, t-butyl methyl ether etc. can be used for lipase reactions run in a synthetic direction (to avoid hydrolysis) (Bose and Keharia, 2013;Carvalho et al, 2015;Devi et al, 2017). In this paper we will focus on the third case, where water-immiscible solvents are used in a distinct phase from the aqueous phase, to form a two-liquid phase system.…”