Study on response surface methodology (RSM) of lipase-catalyzed synthesis of palm-based wax ester

Abstract

The synthesis of wax ester using refined, bleached and deodorized (RBD) palm oil and oleyl alcohol catalyzed by lipozyme IM was carried out. Response surface methodology (RSM) based on a five-level, four-variable central composite rotatable design (CCRD) was used to evaluate the interactive effects of synthesis, of reaction time (2.5-10 h), temperature (30-70 °C), amount of enzyme (0.1-0.2 g) and substrate molar ratio (palm oil to oleyl alcohol, 1:1-1:5) on the percentage yield of wax esters. The optimum conditions derived via RSM were: reaction time 7.38 h, temperature 53.9 °C, amount of enzyme 0.149 g, and substrate molar ratio 1:3.41. The actual experimental yield was 84.6% under optimum condition, which compared well to the maximum predicted value of 85.4%.

Response surface methodological approach for optimizing production of geranyl propionate catalysed by carbon nanotubes nanobioconjugates

“…Increasing of the temperature had a significant effect on the reaction yield, which could be attributed to greater unfolding of the enzyme protein at elevated temperatures. [9] With regards to the log P of the solvent, the polarity of solvents, employed in the enzyme-catalysed esterification reactions, has been reported to affect the enzyme activity, [18] whereby the non-polar solvents (log P > 2) are reported to result in more favourable conditions for many lipase-catalysed reactions. [34] Effect of solvent log P and molar ratio Figure 5 depicts the response surface plot as a function of solvent (log P) versus molar ratio on the CRL-MWCNTs catalysed production of geranyl propionate at constant conditions of 6 h and 50 C. The F-value indicated that the effect of solvent log P (F-value D 152.02) was more significant, as compared to the molar ratio of geraniol:propionic acid (F-value D 2.26).…”

“…[33] It has been suggested that around the critical molar ratio, the alcohol molecules are competing for the same active site, as the acyl group of the acid reduces for the formation of an acyl-enzyme complex and, consequently, are reducing the rate of alcoholysis. [18] It is pertinent to highlight that the presence of excess alcohol molecules in an enzyme-catalysed esterification reaction is predisposed to promote distortion of the essential water layer from the enzyme molecules. [16] Effect of temperature and solvent log P Figure 4 illustrates the effect of varying temperature and solvent log P on the esterification production of geranyl propionate at constant conditions of 6 h and a geraniol:propionic acid molar ratio of 3:1.…”

“…[17] This method uses multiple variables to establish optimum conditions under predetermined reaction preferences, such as high product yield at the lowest cost and/or with the least number of experiments. [18] To facilitate optimization of processes or products, RSM exploits quantitative data in experimental design to conclude and simultaneously resolve multivariate equations. [19] The technique has been successfully applied to optimize enzyme-catalysed synthesis of various esters.…”

Application of Fuzzy Modeling and Optimization in Enzymatic Esterification Process

“…Figure 5(D) shows that the effect of substrate molar ratio on the reaction yield is more significant than temperature. In fact, the presence of larger amounts of substrate increases the probability of substrate and enzyme collision [32]. Increase in the yield with increasing alcohol:acid molar ratio can also be assigned to better solubility of the solid acid in higher amounts of alcohol, and reduction of viscosity of the reaction mixture.…”

Self-assembly of Palm Kernel Oil Wax Esters in Aqueous Media: A Molecular Dynamics Study

“…Palm kernel oil-based wax ester (PKOEs) is consisted of oleyl caprylate (7.65%), oleyl caprate (6.69%), oleyl laurate (50.08%), oleyl myristate (11.53%), oleyl palmitate (3.78%), oleyl stearate (1.49%), oleyl oleate (11.42%), and oleyl linoleate (3.15%) (Gunawan et al, 2005). A spot from the isotropic region of ternary phase diagram with a ratio of 75:5:20 containing Water:PKOEs:Tween80 was chosen to calculate the total number of molecules (Salim et al, 2012).…”