Exploiting the pressure effect on lipase‐catalyzed wax ester synthesis in dense carbon dioxide

Abstract

The present work focuses on the thermodynamic interpretation of the lauryl oleate biosynthesis in high-pressure carbon dioxide. Lipase-catalyzed lauryl oleate production by oleic acid esterification with 1-dodecanol over immobilized lipase from Rhizomucor miehei (Lipozyme RM IM) was successfully performed in a sapphire window batch stirred tank reactor (BSTR) using dense CO(2) as reaction medium. The experiments were planned to elucidate the pressure effect on the reaction performance. With increasing the pressure up to 10 MPa, the catalytic efficiency of the studied enzyme improved rising up to a maximum and decreased at higher pressure values. Kinetic observations, exhibiting that dense CO(2) expanded reaction mixture in subcritical conditions led to higher performance than when diluted in a single supercritical phase, were elucidated by phase-equilibrium arguments. The experimental results were justified with emphasis on thermodynamic interpretation of the studied system. Particularly, the different reaction performances obtained were related to the position of the operating point with respect to the location of liquid-vapor phase boundaries of the reactant fatty acid/alcohol/CO(2) ternary system. The outlook for exploitation of CO(2) expanded phase at lower pressure compared to supercritical phase, with heterogeneous system in which the solid catalyst particles are exposed to dense CO(2) expanded reaction mixture, in developing new biotransformation schemes is promising.

Optimization of Lipase‐Catalyzed Synthesis of Cetyl Octanoate in Supercritical Carbon Dioxide

“…However, a similar result was also reported in a study of lavandulol esterification [26]. On the other hand, Knez et al and Laudani et al [14,16] demonstrated the highest degree of wax ester synthesis is at 10 MPa, and that if the pressure was out of the range 8. 27-12.41 MPa the degree of esterification significantly decreased.…”

“…Several detailed review papers on enzymatic reactions in supercritical fluids (SCF) have been reported and published [12,13]. Enzymatic synthesis of wax esters in SC-CO 2 is organic solvent-free, with the extra advantages of easy separation of unreacted substances, high diffusivity, low viscosity, and low surface tension [14,15]. There have been a few studies regarding lipase-catalyzed synthesis of wax esters in SC-CO 2 .…”

“…There have been a few studies regarding lipase-catalyzed synthesis of wax esters in SC-CO 2 . This includes synthesis of lauryl oleate [14], n-octyl oleate [16], and citronellol laurate [17] in SC-CO 2 . So far, there has been no reported study regarding lipase-catalyzed synthesis of cetyl octanoate in SC-CO 2 .…”

Synthesis of eugenyl acetate by enzymatic reactions in supercritical carbon dioxide

“…The positive effect can be related to the increase of CO 2 density with pressure, which improves its solvation power in the reaction medium [20]. In turn, the negative effect on the conversion can be connected with the dilution of the substrates caused by the greater amount of CO 2 pumped into the reactor, causing an increase in the molar ratio between SC-CO 2 and substrates [20,38]. Knez et al [38] studied the effect of pressure on the conversion of free fatty acid into fatty acid ester using lipase from Rhizomucor miehei (Lipozyme RM IM) in dense CO 2 .…”

Synthesis activity-based zymography for detection of lipases and esterases

“…Dodecyl oleate is a wax ester that has lubricant, pharmaceutical and cosmetic applications (Knez et al 2007). Because wax esters are usually water-insoluble, like dodecyl oleate, we believe that it is possible to use a variety of wax ester synthesis reactions for the lipase and esterase zymography.…”