Synthesis Of Sugar Esters Research Articles

Synthesis of Sugar Esters Using Maize Seed Lipase as a Biocatalyst

This work is devoted to the extraction of a lipase from maize seeds obtained at low cost without extensive purification technology and used as a biocatalyst in the synthesis of various sugar esters as potential biosurfactants in the detergent industry. Indeed, several reactions have been carried out between different sugars - namely glucose, galactose, saccharose, lyxose, fructose and sorbitol - and stearic acid in a ratio of 2.5:1 in hexane at 50 °C. Kinetic monitoring of the target reactions was carried out by volumetric analysis in order to determine the conversions (C). The best results obtained were C = 76, 71 and 67% in the presence of glucose, lyxose and galactose, respectively. In addition, HPLC and TLC analyses revealed that for every sugar used two types of esters formed.

Improving the environmental compatibility of enzymatic synthesis of sugar-based surfactants using green reaction media

The enzymatic synthesis of sugar-based surfactants is often performed in non-conventional media that do not meet any longer the current environmental acceptability, especially for biodegradability and cytotoxicity. In this work, we propose innovative sustainable routes by replacing the current reference organic solvent, 2-methyl-2-butanol (2M2B) by either 2-methyltetrahydrofuran (MeTHF), an agrosolvent, or 2-methyltetrahydrofuran-3-one (MeTHF-3-one), a food-grade ingredient used as solvent. These two neoteric solvents were thus evaluated as reaction media via a lipase-catalyzed esterification of glucose by lauric acid and revealed a novel matter of interest. The regioselectivity of the reaction was mainly directed toward the primary alcohol of glucose maintaining the end-product obtained in 2M2B: D-glucose-6-O-laurate. The PLS-Surface Response Design evidenced enzymatic performances in ester production of 48% in MeTHF and 79% in MeTHF-3-one. The latter solvent resulted not only in better yields compared to 2M2B, but also in an increased enzymatic stability, allowing better reuse of the catalyst. MeTHF-3-one has been shown to be readily biodegradable according to OECD standards. Herein, this solvent has been substantiated for the first time as a green medium in an efficient, selective and sustainable enzymatic synthesis of sugar esters.

Efficient Acylation of Sugars and Oligosaccharides in Aqueous Environment Using Engineered Acyltransferases

A major challenge for the enzymatic synthesis of sugar esters is the low solubility of sugars in anhydrous, often toxic, organic solvents. We overcame this limitation by using acyltransferases for ...

Controlling reaction selectivity for sugar fatty acid ester synthesis by using resins with different basicities

A strongly basic ion-exchange resin catalyst was reported to exhibit a high catalytic activity in transesterification to produce a bio-based surfactant, sugar ester under mild condition. However, the side-reactions to decompose the reactant and the product were found to occur. This study was aimed to improve the selectivity of sugar ester synthesis by newly focusing on the basicity of the resin. A weakly basic resin (Diaion WA20) with a lower mass transfer resistance suppressed the decompositions while maintaining synthesis rate. Controlling molar ratio of the reactants in the intraparticle reaction field also increased the reaction selectivity, 72.1% and product yield, 57.5%. Both values were drastically increased compared to the reported values with the strongly basic resin (selectivity 50.9%, yield 14.3%). This is the first knowledge to show a high catalytic activity of weakly basic resin. These results suggest that a more efficient continuous production process would be possible.

Synthesis of Sucrose Fatty Acid Esters by Using Mixed Carboxylic-fatty Anhydrides.

Fatty acid sugar esters are non-ionic surfactant active agents with excellent performance and many uses. This work is devoted to the synthesis of sugar esters by the esterification reaction of sugar with mixed carboxylicpalmitic anhydrides using resin Amberlyst-15 as heterogeneous acid catalyst. These anhydrides should be stable and react as acylating agents. Influence of different reaction parameters, such as the molar ratio (sucrose/anhydride), the type of solvent and the reaction time on the yield of the esterification reaction were studied. The esterification reaction of sucrose with mixed palmitic benzoic anhydride leads to a mixture of sucrose esters of palmitic acid with a good percentage of conversion. The mixed anhydride was both reactive and selective for the preparation of fatty acid ester.

Influence of Chemical Modifications of Polyhydroxyalkanoate-Derived Fatty Acids on Their Antimicrobial Properties

Sugar esters are bioactive compounds derived from renewable resources. They consist of a sugar moiety with attached non-polar part – usually a fatty acid. These compounds find uses in cosmetic, food and pharmaceutical industries as surfactants due to their physicochemical and antimicrobial activities. In this study we have produced fatty acids for sugar ester synthesis from bacterially derived polyesters, namely polyhydroxyalkanoates (PHAs). We have developed methodology to decorate PHA monomers with a fluorinated moiety. With aid of biocatalysis a series of glucose esters was created with unmodified and modified PHA monomers. All synthesised compounds showed moderate antimicrobial activity.

Fermented Solids and Their Application in the Production of Organic Compounds of Biotechnological Interest.

We review the application of dry fermented solids (DFS) containing naturally immobilized enzymes as catalysts in synthesis and in hydrolysis reactions. The most studied application is the use of DFS containing lipases in the synthesis of biodiesel esters, by transesterification of oils or by esterification of fatty acids with short-chain alcohols in solvent-free reaction media. Other applications of DFS that have been studied include the use of DFS containing pectinases to liberate D-galacturonic acid from pectin and the production of high-value compounds by DFS containing lipases, such as the synthesis of sugar esters and the production of pure enantiomers by resolution of racemic mixtures. To date, studies are limited to proof of concept, and there are still many challenges to be faced in the development of industrial-scale processes using DFS as catalysts. A key challenge is the relatively low activity of DFS compared to commercial enzyme preparations. Attention needs to be given to scale up, not only of the bioreactor for the application of the DFS but also for the production of the fermented solids. There is also a need for economic feasibility studies to determine whether the production of DFS and their use as catalysts can be competitive at industrial scale. Graphical Abstract.

Lipase-Catalyzed Synthesis of Sugar Esters in Honey and Agave Syrup.

Honey and agave syrup are high quality natural products and consist of more than 80% sugars. They are used as sweeteners, and are ingredients of cosmetics or medical ointments. Furthermore, both have low water content, are often liquid at room temperature and resemble some known sugar-based deep eutectic solvents (DES). Since it has been shown that it is possible to synthesize sugar esters in these DESs, in the current work honey or, as vegan alternative, agave syrup are used simultaneously as solvent and substrate for the enzymatic sugar ester production. For this purpose, important characteristics of the herein used honey and agave syrup were determined and compared with other available types. Subsequently, an enzymatic transesterification of four fatty acid vinyl esters was accomplished in ordinary honey and agave syrup. Notwithstanding of the high water content for transesterification reactions of the solvent, the successful sugar ester formation was proved by thin-layer chromatography (TLC) and compared to a sugar ester which was synthesized in a conventional DES. For a clear verification of the sugar esters, mass determinations by ESI-Q-ToF experiments and a NMR analysis were done. These environmentally friendly produced sugar esters have the potential to be used in cosmetics or pharmaceuticals, or to enhance their effectiveness.

Lipase‐catalyzed Synthesis of Sugar Ester in Mixed Biphasic System of Ionic Liquids and Supercritical Carbon Dioxide

Lipase‐catalyzed synthesis of lauroyl glucose ester was continuously performed in a biphasic system consisting of supercritical CO2 and an ionic liquid (IL). Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy are employed to identify the product lauroyl glucose ester. The effects of reaction pressure, temperature, substrate flow rate, the amount of enzyme, and the amount of IL on the glucose conversion rate are investigated. The highest glucose conversion of up to 95.5% could be achieved at the optimal condition, which is higher than that in the pure IL. The enzyme activity in the biphasic system was 18.19 μmol/g/min, which is much higher than that in the pure IL. The continuous reaction in the binary system could last for 10 h at high enzyme activity. The combination of supercritical CO2 and ILs could not only improve the reaction rate and yield, which are attributed to the fast mass transfer rate and enhanced enzyme activity and lifespan, but also make the product separation and enzyme/ILs recycling easier.

Biocatalytic acylation of glucose by immobilized Ricinus Communis lipase

The aim of the present study is the enzymatic synthesis of sugar ester catalyzed by an immobilized lipase from the seeds of castor oil plant (R icinus communis ). Experiments were focused on the synthesis of a glucose ester by selecting different acyl donors in different organic solvents. The highest esterification yield was obtained with palmitic acid in tert-Butanol. Effects of different parameters (temperature, water activity, glucose/palmitic acid molar ratio and immobilized lipase activity) on the synthesis of glucose palmitate were studied by varying one factor at a time. Maximum conversion yield (65%) was obtained under the optimized conditions: temperature (40 °C), glucose/palmitic acid molar ratio (1:2), water activity (0.3), stirring rate (600 rpm), lipase activity 2.7 U and reaction time (8 h). The structural characteristics of glucose palmitate were confirmed by FT-IR, 1 H and 13 C- NMR analysis. The glucose palmitate could reduce the surface tension of water from 72 to 42 mN/m with a CMC of 0.1 g/L.

Impacts of ionic liquids on enzymatic synthesis of glucose laurate and optimization with superior productivity by response surface methodology

As biosurfactants derived from naturally renewable resources, sugar fatty acid esters have broad applications in food, cosmetic and pharmaceutical industries. Glucose laurate was synthesized by a lipase-catalyzed acylation of glucose with vinyl laurate in ionic liquid (IL) systems. 16 ILs were screened for investigating the impact of the IL’s compositions on both the solvent properties of the IL and the synthetic process. The conversions obtained in ILs showed a bell-shaped relationship with their log P values. ILs that carry hydrophobic cations and hydrophilic anions seemed to favor the sugar ester synthesis. 1-Hexyl-3-methylimidazolium trifluoromethylsulfonate ([HMIm][TfO]) was selected both as a pure solvent and as a co-solvent with 2-methyl-2-butanol (2M2B) for this application, and the influence of the affecting factors (such as reaction temperature, enzyme amount, molar ratio of the two substrates, and reaction time) has been studied. Response surface methodology (RSM) was applied to optimize the [HMIm][TfO]/2M2B bisolvent system, and an optimal productivity of 14.2mmol/L/h was achieved, which is superior to other literature results.

Enhanced production of fructose ester by biocatalyzed continuous flow process

Abstract Background Fatty acid sugar esters are non-toxic, odorless, non-irritanting surfactants. They can be synthesized by renewable resources and are completely biodegradable in aerobic and anaerobic conditions. Their application has been expanded in innumerous areas including pharmaceuticals, cosmetics, detergents and food industry. Lipase-catalyzed esterification have been investigated as a potential substitute to the traditional chemical, demanding milder reaction conditions, allowing better reaction control and providing higher-quality products. So, the lipase catalyzed sugar ester synthesis becomes an interesting strategy for producing biodegradable, non- ionic surfactants. The main disadvantage of this protocol is the poor solubility of substrates and long reaction time required for performed the esterification reaction with moderated to good yields. Results Here in, we report the enzymatic esterification of steric hindered fructose derivative with free fatty acids derived from palm oil refining process (RePO) under continuous flow conditions at concentrations up to 0.5 M, increasing the productivity up to 100 mg. min −1.g immob. enzyme −1. Conclusions The immobilized commercial enzyme from Rhizomucor miehei generated the best performance between the catalysts tested.

Heterofunctional Hydrophilic–Hydrophobic Porous Silica as Support for Multipoint Covalent Immobilization of Lipases: Application to Lactulose Palmitate Synthesis

Lipase-catalyzed synthesis of sugar esters, as lactulose palmitate, requires harsh conditions, making it necessary to immobilize the enzyme. Therefore, a study was conducted to evaluate the effect of different chemical surfaces of hierarchical meso-macroporous silica in the immobilization of two lipases from Pseudomonas stutzeri (PsL) and Alcaligenes sp. (AsL), which exhibit esterase activity. Porosity and chemical surface of silica supports, before and after functionalization and after immobilization, were characterized by gas adsorption and Fourier transform infrared (FTIR) spectroscopy. PsL and AsL were immobilized in octyl (OS), glyoxyl (GS), and octyl-glyoxyl silica (OGS). Hydrolytic activity, thermal and solvent stability, and sugar ester synthesis were evaluated with those catalysts. The best support in terms of expressed activity was OS in the case of PsL (100 IU g(-1)), while OS and OGS were the best for AsL with quite similar expressed activities (60 and 58 IU g(-1), respectively). At 60 °C in aqueous media the more stable biocatalysts were GS-PsL and OGS-AsL (half-lives of 566 and 248 h, respectively), showing the advantage of a heterofunctional support in the latter case. Lactulose palmitate synthesis was carried out in acetone medium (with 4% of equilibrium moisture) at 40 °C obtaining palmitic acid conversions higher than 20% for all biocatalysts, being the highest of those obtained with OGS-AsL and OS-PsL. Therefore, screening of different chemical surfaces on porous silica used as supports for lipase immobilization allowed obtaining active and stable biocatalyst to be employed in the novel synthesis of lactulose palmitate.

Lipase‐catalyzed synthesis of secondary glucose esters under continuous flow conditions

AbstractChemical methods for the synthesis of sugar esters require the use of high temperatures in the presence of alkaline catalysts resulting in undesirable by‐products and low regiosselectivity. Sugar‐based fatty acid esters are non‐ionic, biodegradable, odorless, non‐irritating, non‐toxic surfactants widely used pharmaceuticals, cosmetics, detergents, and food industry. Here in we report our results on enzymatic esterification of protected glucose (glucose ketal) with several fatty acids using the immobilized lipase from Rhizomucor miehei under batch and continuous flow conditions, to afford new glucose derivatives with potential surfactant properties. The results presented here shows that high conversions can be obtained in short reaction time.Practical application: The research of new non‐toxic, environmentally friendly and biodegradable surfactants to replace chemicals has increased along with the development of green chemistry. Nonionic biosurfactants, such as sugar fatty acid esters, may be obtained by enzymatic synthesis, a simple manufacturing method for application in several areas, including food, cosmetic, detergent, and pharmaceutical industry. In this work we have described the uncommon esterification of a steric hindered secondary hydroxyl group on glucose ketal leading to new glucose derivatives with potential application as surfactants.

ChemInform Abstract: Enzymatic Synthesis of Sugar Fatty Acid Esters in Ionic Liquids

AbstractReview: 40 refs.

Lipase-catalyzed esterification of steric hindered fructose derivative by continuous flow and batch conditions

The lipase catalyzed sugar ester synthesis is an interesting strategy for producing biodegradable, non-ionic surfactants. The main disadvantage of this protocol is the long reaction time required for achieving moderated to good yields. Here, we report the esterification of steric hindered fructose derivative where important variables for batch conditions were identified by the use of a RSM protocol and then translated to the continuous flow regime with high conversions and short residence times.

Sugar Ester Synthesis by Thermostable Lipase from Streptomyces thermocarboxydus ME168

The extracellular lipase from Streptomyces thermocarboxydus ME168 was purified to 9.5-fold with 20% yield, following concentration by acetone precipitation, ion exchange chromatography (Resource Q) and gel filtration chromatography (Superdex 200), respectively. The purified enzyme had an apparent molecular mass of 21 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The N-terminal sequence of the lipase was ASDFDDQILG and was different from most other reported lipase. The enzyme showed maximum activity at 50 °C with the half-life of 180 min at 65 °C. It showed high stability at a broad pH range of 5.5-9.5 and was thermostable at the temperature range of 25-60 °C. The K(m) and V(max) were 0.28 mM and 1,428 U/mg, respectively, using p-nitrophenyl palmitate as substrate. It was active toward p-nitrophenyl ester with medium to long acyl chain (C(8)-C(16)). Lipase activity was inhibited by Zn(2+), dithiothreitol (DTT), EDTA and some organic solvents, e.g., ethanol, acetone, dioxane, acetronitrile, tert-butanol and pyridine. Immobilized crude lipase of S. thermocarboxydus ME168 on celite could be used to synthesize sugar esters from glucose and vinyl acetate, vinyl butyrate or vinyl caproate in tert-butanol:pyridine (55:45 v/v) at 45 °C with conversion yields of 93, 67 and 55%, respectively.

Enzymatic synthesis of sugar fatty acid esters in ionic liquids

Sugar fatty acid esters are nonionic biosurfactants widely used in food, cosmetic and pharmaceutical industries. Ionic liquids (ILs) have shown great potential as an alternative reaction medium to conventional organic solvents for their enzymatic synthesis, promoting a significant enhancement in sugar solubility, enzymatic reactivity and regioselectivity. In this perspective, we summarize the advances in the use of ILs as a solvent for sugar dissolution and lipase-catalyzed sugar ester synthesis, review the recent achievements in designing enzyme-compatible ILs for the synthesis, and discuss the challenges that the research on this topic is facing. Among the advanced ILs, deep eutectic solvents (DESs) merit a serious consideration as a potential reaction medium for this application.

Enzymatic synthesis of sugar esters and their potential as surface-active stabilizers of coconut milk emulsions

Sugar esters are compounds with surfactant properties (biosurfactants), i.e., capable of reducing the surface tension and promote the emulsification of immiscible liquids. On the other hand, as with all emulsions, coconut milk is not physically stable and is prone to phase separation. Therefore, the aim of this work was to evaluate the synthesis of fructose, sucrose and lactose esters from the corresponding sugars using Candida antarctica type B lipase immobilized in two different supports, namely acrylic resin and chitosan, and evaluate its application in the stabilization of coconut milk emulsions. The enzyme immobilized on chitosan showed the highest yield of lactose ester production (84.1%). Additionally, the production of fructose ester was found to be higher for the enzyme immobilized on the acrylic resin support (74.3%) as compared with the one immobilized on chitosan (70.1%). The same trend was observed for the sucrose ester, although with lower percentage yields. Sugar esters were then added to samples of fresh coconut milk and characterized according to their surface tension, emulsification index and particle size distribution. Although the microscopic analysis showed similar results for all sugar esters, results indicated lactose ester as the best biosurfactant, with a surface tension of 38.0 N/m and an emulsification index of 54.1%, when used in a ratio of 1:10 (biosurfactant:coconut milk, v/v) for 48 h experiments.

Biocatalytic production of lactose ester catalysed by mica-based immobilised lipase

Enzyme immobilisation technology is an effective means to improve sugar ester production through the employment of biocatalysts. In the present study, immobilisation of Candida rugosa (CRL) lipase onto amino-activated mica is performed via covalent bonding (namely Amino-CRL) and the cross-linking of lipases into nano-reactors through physical adsorption (namely NER-CRL). Free and immobilised lipases were tested for their esterification activities. Specific activities for Amino-CRL and NER-CRL increased by 2.4 and 2.6-fold, respectively, upon immobilisation. Extending this work, immobilised lipases have novel capabilities in the synthesis of sugar esters. The optimised conditions for sugar fatty acid ester syntheses are 48h at 2:1 of molar ratio of lactose sugar to capric acid at 55°C. Furthermore, a high operational stability with half-lives of over 13 and 10 runs was achieved for NER-CRL and Amino-CRL, respectively, indicating the efficiency of the immobilisation process.