Lipase-catalyzed esterification of lactic acid in supercritical carbon dioxide

Synthesis of eugenyl acetate by enzymatic reactions in supercritical carbon dioxide

“…On the other side, a decrease on reaction rate can occur due to formation of two phases (liquid and gas) [20]. Therefore, phase behavior experiments were performed through a static method without sampling in a high-pressure variable-volume view cell.…”

“…A positive effect of pressure at 40 • C and a negative effect at 50 and 60 • C can be observed on Table 3. 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].…”

“…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 .…”

“…The data on Table 4 show that the conversion and specific productivity of eugenyl acetate decreased continuously with the increasing number of cycles. The catalytic ability of the lipase CALB (Candida antarctica lipase B) in an immobilized form decreases with the increase of the utilization cycles [20] or depressurization/pressurization cycles [24,25]. The reduction of enzyme activity after SC-CO 2 exposure has been related to several reasons.…”

New findings about the lipase acetylation of nanofibrillated cellulose using acetic anhydride as acyl donor

“…The main advantages of this reaction medium are that it is a clean, nontoxic, inert, non-flammable and the fact that it can be removed easily after the reaction by pressure relief (Gremos et al, 2012;Knez et al, 2012;Paljevac, Primožič, Habulin, Novak, & Knez, 2007). ScCO 2 is also highly available and less expensive than conventional organic solvents and has a near-ambient critical temperature (31.1 • C) and moderate critical pressure (7.36 MPa) (Kavčič, Knez, & Leitgeb, 2014;Knez et al, 2012;Paljevac et al, 2007). In addition, because of the low critical temperature, scCO 2 is suitable for processing most biochemicals (Paljevac et al, 2007).…”