Lipase-catalyzed transesterification of ethyl ferulate with triolein in solvent-free medium

Enhanced triolein and ethyl ferulate interesterification performance by CRL-AuNPs

This study established a Candida rugosa lipase (CRL) system to catalyze triolein and ethyl ferulate interesterification. The products were identified, and the binding mode between the substrates and CRL was predicted through molecular docking. Three methods for preparing CRL-AuNPs were proposed and characterized. It was found that the addition of 40 mL of 15 nm gold nanoparticles increased the CRL activity from 3.05 U/mg to 4.75 U/mg, but the hybridization efficiency was only 32.7 %. By using 4 mL of 0.1 mg/mL chloroauric acid, the hybridization efficiency was improved to 50.7 %, but the enzyme activity was sharply decreased. However, when the molar ratio of Mb to HAuCl4 was 0.2, the hybridization efficiency increased to 71.8 %, and the CRL activity was also enhanced to 5.98 U/mg. Under optimal conditions, the enzyme activity of CRL-AuNPs③ was maintained at 95 % after 6 repetitions and 85.6 % after 30 days at room temperature.

Choline Chloride-urea Deep Eutectic Mixture Water for the Synthesis of an Amphiphilic Compound of Glyceryl Monocaffeate

The Lipase-catalyzed synthesis of glyceryl monocaffeate (GMC) in choline chloride-urea of natural deep eutectic solvent (NADES) media is reported to provide amphiphilic character to caffeic acid (CA). The modification of CA into GMC could potentially increase its solubility and widen the application of CA's biological activities in water and oil-based systems. The high conversion was achieved when the reaction was carried out with the addition of more than 20 %v/v water, at a high molar ratio of glycerol and 40°C. It was found that the lipase-catalyzed transesterification of ethyl caffeate (EC) and glycerol in choline chloride-urea of DES media obeyed ping-pong bi-bi mechanism with V_max = 10.9 mmol.min^-1, K_mEC = 126.5 mmol and K_mGly = 1842.7 mmol.

A Simple and Efficient Method for Synthesis and Extraction of Ethyl Ferulate from γ-Oryzanol

Ethyl ferulate (EF) is a ferulic acid (FA) derivative with high commercial value. It is not found naturally and is mostly synthesized from FA via esterification with ethanol. The present work aimed to synthesize the EF from γ-oryzanol, a natural antioxidant from rice bran oil via acid-catalyzed transethylation at refluxing temperature of ethanol. The reaction was optimized by central composite design (CCD) under response surface methodology. Based on the CCD, the optimum condition for the synthesis of EF from 0.50 g of γ-oryzanol was as follows: γ-oryzanol to ethanol ratio of 0.50:2 (g/mL), 12.30% (v/v) H₂SO₄, and a reaction time of 9.37 h; these conditions correspond to a maximum EF yield of 87.11%. Moreover, the optimized transethylation condition was further validated using 12.50 g of γ-oryzanol. At the end of the reaction time, distilled water was added as antisolvent to selectively crystallize the co-products, phytosterol and unreacted γ-oryzanol, by adjusting the ethanol concentration to 49.95% (v/v). The recovery yield of 83.60% with a purity of 98% of EF was achieved. In addition, the DPPH and ABTS assays showed similar antioxidant activities between the prepared and commercial EF.

Synthesis of Ibuprofen Monoglyceride in Solventless Medium with Novozym®435: Kinetic Analysis

This study investigates the enzymatic esterification of glycerol and ibuprofen in a solventless medium catalyzed by immobilized lipase B from Candida antarctica (Novozym®435). Fixing the concentration of this enzymatic solid preparation at 30 g·L−1, and operating at a constant stirring speed of 720 rpm, the temperature was changed between 50 and 80 °C, while the initial concentration of ibuprofen was studied from 20 to 100 g·L−1. Under these conditions, the resistance of external mass transport can be neglected, as confirmed by the Mears criterion (Me < 0.15). However, the mass transfer limitation inside the pores of the support has been evidenced. The values of the effectiveness factor (η) vary between 0.08 and 0.16 for the particle size range considered according to the Weisz–Prater criteria. Preliminary runs permit us to conclude that the enzyme was deactivated at medium to high temperatures and initial concentration values of ibuprofen. Several phenomenological kinetic models were proposed and fitted to all data available, using physical and statistical criteria to select the most adequate model. The best kinetic model was a reversible sigmoidal model with pseudo-first order with respect to dissolved ibuprofen and order 2 with respect to monoester ibuprofen, assuming the total first-order one-step deactivation of the enzyme, with partial first order for ibuprofen and enzyme activity.

Comparative Study of Soybean Oil and the Mixed Fatty Acids as Acyl Donors for Enzymatic Preparation of Feruloylated Acylglycerols in Ionic Liquids

Feruloylated acylglycerols (FAGs) are the lipophilic derivatives of ferulic acid. In this work, soybean oil (SBO) and the mixed fatty acids (MFA) were selected as fatty acyl donors, and reacted with glyceryl monoferulate (GMF) to prepare FAGs in ionic liquids (ILs). Effect of various reaction parameters (time, temperature, enzyme concentration, and substrate ratio) and ILs on the GMF conversion and the reaction selectivity for FAGs formation were investigated. Response surface methodology (RSM) based on a 3-level-4-factor Box-Behnken experimental design was employed to evaluate the inactive effect of reaction parameters. For the esterification of GMF with MFA, the maximum GMF conversion (98.9 ± 0.9%) and FAG yield (88.9 ± 0.6%) were achieved in [C10mim]PF6. However, for the transesterification of GMF with SBO, the maximum GMF conversion (94.3 ± 0.7%) and FAG yield (83.8 ± 1.0%) were obtained in [C12mim]PF6. High FAG selectivities (∼0.90) were also obtained using SBO or MFA as acyl donors.

Improvement on the Catalytic Performance Using Dual Lipases System in the Synthesis of Ferulate Esters

A novel approach of dual lipases system was successfully carried out in improving the synthesis of ferulate esters between ethyl ferulate and olive oil. Combination of Novozym 435 and Lipozyme RMIM were used as biocatalyst to improve the reaction performance. Different reaction parameters (ratio of lipases, reaction time, lipase dosage, substrate molar ratio and reaction temperature) were analyzed systematically. A high conversion of ferulate esters (85%) was obtained after 12 hrs of reaction time at optimal conditions of 1:9 w/w (Novozym 435/Lipozyme RMIM), 80 mg of lipase and 1:4 ethyl ferulate:olive oil at 60 oC.

High Yield Synthesis of Kojic Ester Using Dual Enzymes System and their Antibacterial Activity

Enzymatic synthesis of kojic ester, a bio-based whitening agent, was successfully carried out via esterification reaction between oleic acid and kojic acid. Commercial immobilized lipases of Novozym 435 and Lipozyme RM IM were used in combination as biocatalyst in the reaction system. Various reaction parameters were chosen to optimize the reaction in order to obtain a high yield of kojic ester including the best ratio of lipases, reaction time and reaction temperature. The optimum conditions for the synthesis of kojic ester was achieved at reaction time of 12 hours, temperature of 60 οC and equal ratio of lipases to produce more than 70 % yield. Antimicrobial tests of synthesized kojic ester towards several types of bacteria via Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) analyses were also examined. The results obtained suggested that kojic ester exhibits a good bactericidal effect towards all bacteria tested such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium.

Kinetics of transesterification of olive oil with methanol catalyzed by immobilized lipase derived from an isolated Burkholderia sp. strain

This work was carried out to investigate the acyl migration phenomena which has been considered as the factor having significant impact on kinetics of transesterification of oils catalyzed by a Burkholderia lipase with 1,3-regioselectivity. Transesterification of olive oil with methanol catalyzed by the immobilized lipase produces various intermediates, including 1-monoglyceride, 2-monoglyceride, 1,2-diglyceride, and 1,3-diglyceride. Migration kinetics of fatty acid groups from sn-2 of 2-monoglyceride and 1,2-diglyceride to 1-monoglyceride and 1,3-diglyceride were investigated for the temperature range of 25-65°C. The kinetics of transesterification of olive oil with methanol involving acyl migration in the presence of water was also systematically studied at 25, 40, and 65°C. Increasing temperature could increase the acyl migration rate. The overall biodiesel conversion was improved from 73.4% (at 25°C) to 90.0% and 92.4% when conducting at 40 and 65°C, respectively. Thermodynamics aspects of equilibrium state of the immobilized lipase-catalyzed transesterification were also discussed.