Strategies to obtain high content of monoacylglycerols

Improved Synthesis of α-Glycerol Monolaurate Using Lipozyme TL IM

This study aimed to synthesize α-Glycerol Monolaurate from protected glycerol (glycerol 1,2-acetonide) using Lipozym TL IM as a catalyst. In the first step, transesterification of methyl laurate and glycerol 1,2-acetonide with Lipozyme TL IM produced 1,2-acetonide-3-lauryl glycerol. In the second step, deprotection of 1,2-acetonide-3-lauryl glycerol with Amberlyst-15 produced α-Glycerol Monolaurate. Furthermore, the optimum yield (82.1%) of 1,2-acetonide-3-lauryl glycerol (light yellow liquid, purity of 92%) was achieved at a reactant mole ratio of 1, n-hexane (4 mL) with a reaction time of 12 hours, and total Lipozyme TL IM of 5% (w/w of the total weight of reactants) at a temperature of 35°C. Deprotection of 1,2-acetonide-3-lauryl glycerol with Amberlyst-15 was conducted at room temperature for 24 hours. At a melting point of 62.8°C, and purity of 100% α-Glycerol Monolaurate in the form of a white solid was obtained with a yield of 74.6% after the recrystallization of the crude product. This α-glycerol monolaurate synthesis reaction pathway can be referred to as a green α-monoacylglyceride synthesis method.

Sodium Silicate Catalyst for Synthesis Monoacylglycerol and Diacylglycerol-Rich Structured Lipids: Product Characteristic and Glycerolysis–Interesterification Kinetics

Sodium silicate as heterogeneous base catalysts is more environmentally friendly and easily separated by filtration. The objective of this research was to evaluate the activated sodium silicate as catalyst for synthesis of monoacylglycerol (MAG) and diacylglycerol (DAG)-rich structured lipids (SLs) from a palm olein-stearin blend. Sodium silicate was activated and functional group was characterized. Reaction was performed using 5% catalyst (w/w) at various reaction temperature (70–120 °C) for 3 h in a batch stirred tank reactor. Physical properties of SLs, such as melting point, slip melting point, and hardness of SLs were determined. Reaction kinetics were also evaluated. The results show that Si−O bending was reduced and shifted to a Si−O−Na and Si−O−Si functional groups after sodium silicate activation. Temperature had a significant effect on SLs composition at higher than 90 °C. An increase in temperature produced more MAG, resulting in better product physical properties. The best reaction condition was at 110 °C. Rate constants and the Arrhenius equation were also obtained for each reaction step. In summary, the activated sodium silicate catalyzed glycerolysis-interesterification reaction, which produced MAG and DAG at temperature higher than 90 °C. Therefore, the physical properties of SLs were improved. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Integrated bioprocess for structured lipids, emulsifiers and biodiesel production using crude acidic olive pomace oils

Olive pomace oil (OPO), a by-product of olive oil industry, is directly consumed after refining. The novelty of this study consists of the direct use of crude high acidic OPO (3.4-20% acidity) to produce added-value compounds, using sn-1,3-regioselective lipases: (i) low-calorie dietetic structured lipids (SL) containing caprylic (C8:0) or capric (C10:0) acids by acidolysis or interesterification with their ethyl esters, (ii) fatty acid methyl esters (FAME) for biodiesel, and (iii) sn-2 monoacylglycerols (emulsifiers), as by-product of FAME production by methanolysis. Immobilized Rhizomucor miehei lipase showed similar activity in acidolysis and interesterification for SL production (yields: 47.8-53.4%, 7 h, 50℃) and was not affected by OPO acidity. Batch operational stability decreased with OPO acidity, but it was at least three-fold in interesterification that in acidolysis. Complete conversion of OPO into FAME and sn-2 monoacylglycerols was observed after 3 h-transesterification (glycerol stepwise addition) and lipase deactivation was negligeable after 11 cycles.

Catalytic Synthesis of Monoglycerides by Glycerolysis of Triglycerides

The synthesis of monoglycerides by the transesterification of triglycerides with glycerol was studied using zinc glycerolate as a heterogeneous catalyst.

The effect of the operating variables on the triglyceride conversion and monoglyceride yield was evaluated. The maximum values of triglyceride conversion and monoglyceride yield reached at 2-hour reaction time were 83 and 49 %, respectively. These values were obtained at 240 °C with 3 % catalyst loading and glycerol/oil molar ratio of 6. When the molar ratio of the reactants was increased, the triglyceride conversion and monoglyceride yield achieved an optimum value. This behavior was related with a competitive adsorption of the reagents.

It was possible to reuse the catalyst without significant changes in activity.

Highly Selective Synthesis of Monolaurin via Enzymatic Transesterification under Batch and Continuous Flow Conditions

This study aimed to investigate the highly selective production of monolaurin via enzymatic transesterification of methyl laurate and glycerol. It was determined that a binary solvent system (tert-butanol/iso-propanol, 20:80, wt./wt.) was suitable for the enzymatic production of monolaurin, especially in the continuous process. The highest mass fraction of monolaurin in the product mixture (80.8 wt.%) was achieved in a batch mode under the following conditions: a methyl laurate-to-glycerol molar ratio of 1:6, a substrate concentration (methyl laurate in the binary solvent) of 15 wt.%, an enzyme dosage of 6 wt.% of the amount of methyl laurate, and a reaction time of 1.5 h at 50°C. Compared with the results under the batch conditions, a slightly higher yield of monolaurin (82.5 ± 2.5 wt.%) was obtained in a continuous flow system at a flow rate of 0.1 mL/min, while the mass fraction of dilaurin in the product mixture was only 0.7 ± 0.6 wt.%. In addition, the yield of monolaurin remained almost unchanged during the 18 tested days of the continuous experiment.

Development of a Pichia pastoris whole-cell biocatalyst with overexpression of mutant lipase I PCLG47I from Penicillium cyclopium for biodiesel production

Biodiesel is efficiently produced by a lipase whole-cell biocatalyst with high activity and thermostability at low temperature.

Re-evaluation of mono- and di-glycerides of fatty acids (E 471) as food additives

The EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS) provides a scientific opinion re-evaluating the safety of mono- and di-glycerides of fatty acids (E 471) when used as a food additive. The Panel considered that it is very likely that hydrolysis of mono- and di-glycerides of fatty acids by lipases in the gastrointestinal tract would occur, resulting in the release of glycerol and fatty acids. Glycerol (E 422) and fatty acids (E 570) have been re-evaluated and the Panel concluded that there was no safety concern regarding their use as food additives. Toxicological studies with mono- and di-glycerides rich in unsaturated fatty acids were considered for the re-evaluation of E 471. No evidence for adverse effects was reported in short-term, subchronic studies, chronic, reproductive and developmental toxicity studies. Neither carcinogenic potential nor a promotion effect in initiation/promotion was reported. The available studies did not raise any concern with regard to genotoxicity. The refined estimates were based on 31 out of 84 food categories in which E 471 is authorised. The Panel noted that the contribution of E 471 represented at the mean only 0.8-3.5% of the recommended daily fat intake. Based on the approach described in the conceptual framework for the risk assessment of certain food additives re-evaluated under Commission Regulation (EU) No 257/2010 and taking into account the considerations mentioned above, the Panel concluded that there was no need for a numerical acceptable daily intake (ADI) and that the food additive mono- and di-glycerides of fatty acids (E 471) was of no safety concern at the reported uses and use levels. The Panel recommended some modifications of the EU specifications for E 471.

Purification process for MUFA- and PUFA-based monoacylglycerols from edible oils

Important health benefits have been attributed to monoacylglycerols (MAGs) due to their various physiological functions, owing to which they become candidates for use as functional foods in order to prevent the onset of certain diseases such as colon cancer. In this work, six edible oils, namely: olive, linseed, sunflower, evening primrose, DHASCO^® and ARASCO^® have been processed to obtain different MUFA- and PUFA- based MAGs. First, the oils were hydrolyzed by means of an enzymatic process using porcine pancreatic lipase and then the reaction products were fractionated by using a liquid chromatography column containing silica gel as stationary phase in order to purify the MAGs-enriched fraction. A second chromatography process was performed using silver nitrate coated silica gel as stationary phase, in order to obtain the different MUFA- and PUFA-based MAGs from the corresponding oils. Overall, MAGs based on oleic, linoleic, α-linolenic, γ-linolenic, arachidonic and docosahexaenoic acids have been isolated in high yields and purities (92.6, 97.4, 95.3, 90.9, 100 and 95.3% purity, respectively). Positional distribution was determined by means of ¹H NMR, which revealed a mix of 1(3) and 2-MAGs in variable proportions in the different MAGs.

Enzymatic biodiesel synthesis from yeast oil using immobilized recombinant Rhizopus oryzae lipase

The recombinant Rhizopus oryzae lipase (1-3 positional selective), immobilized on Relizyme OD403, has been applied to the production of biodiesel using single cell oil from Candida sp. LEB-M3 growing on glycerol from biodiesel process. The composition of microbial oil is quite similar in terms of saponifiable lipids than olive oil, although with a higher amount of saturated fatty acids. The reaction was carried out in a solvent system, and n-hexane showed the best performance in terms of yield and easy recovery. The strategy selected for acyl acceptor addition was a stepwise methanol addition using crude and neutralized single cell oil, olive oil and oleic acid as substrates. A FAMEs yield of 40.6% was obtained with microbial oils lower than olive oil 54.3%. Finally in terms of stability, only a lost about 30% after 6 reutilizations were achieved.