Lipase-catalyzed Production and Purification of Palm Esters Using Stirred Tank Reactors (STR).

Lipase-catalyzed production of palm esters was performed via alcoholysis of palm oil and oleyl alcohol in solvent and solvent-free systems using a 2 L stirred tank reactor (STR). Two immobilized lipases were tested and Lipozyme RM IM exhibited superior performance in both reaction systems. Reusability studies of the enzymes in a solvent-free system also demonstrated the high stability of Lipozyme RM IM as shown by its ability to yield more than 70% palm esters with up to 19 cycles of reusing the same enzymes. Modification of the enzyme washing process improved the stability of Lipozyme TL IM in a solvent system as demonstrated by maintaining 65% yield after 5 times of repeated enzyme use. The scale up process for both lipases was conducted in the presence of solvents by using the impeller tip speed approach. Lipozyme RM IM-catalyzed reaction in a 15 L STR produced 85.7% yield and there was a significant drop to 60.7% in the 300 L STR, whereas Lipozyme TL IM had a lower yield (65%) when the reaction volume was increased to 15 L. The low yields could be due to the accumulation of enzymes at the bottom of the vessel. Purification of palm esters via solvent-solvent extraction revealed that more than 90% of oleyl alcohol was extracted after the third extraction cycle at 150 rpm impeller speed with reduced palm esters: ethanol ratio (v/v) from 1:4 to 1:3.

Lipase-catalyzed synthesis of red pitaya (Hylocereus polyrhizus) seed oil esters for cosmeceutical applications: process optimization using response surface methodology.

Esters were synthesized via the alcoholysis of red pitaya seed oil with oleyl alcohol catalyzed by immobilized lipase, Lipozyme RM IM. The effects of synthesis parameters, including temperature, time, substrate molar ratio and enzyme loading, on the yield and productivity of esters were assessed using a central composite response surface design. The optimum yield and productivity were predicted to be about 80.00% and 0.58 mmol h-1, respectively, at a synthesis temperature of 50.5 °C, time of 4 h, substrate molar ratio of 3.4 : 1 and with 0.17 g of enzyme. Esters were synthesized under the optimum synthesis conditions; it was found that the average yield and productivity were 82.48 ± 4.57% and 0.62 ± 0.04 mmol h-1, respectively, revealing good correspondence with the predicted values. The main esters were oleyl linoleate, oleyl oleate, oleyl palmitate and oleyl stearate. The synthesized esters exhibited no irritancy effects and their physicochemical properties showed their suitability for use as cosmeceutical ingredients.