Regioselective Synthesis of Lactulose Esters by Candida antarctica and Thermomyces lanuginosus Lipases

Green Synthesis Optimization of Glucose Palm Oleate and Its Potential Use as Natural Surfactant in Cosmetic Emulsion

This study aimed to optimize the green synthesis of glucose palm oleate catalyzed by Carica papaya Lipase (CPL) through transesterification in a solvent-free system. Palm olein was used as a fatty acid donor for transesterification reactant and was also employed as a reaction medium. Reaction optimization was performed by using response surface methodology (RSM). Seventeen synthesis conditions were generated by a Box–Behnken design and the products were further determined by ultra-performance liquid chromatography (UPLC). Fatty acid compositions of palm olein identified by gas chromatography-mass spectrometry (GC-MS) found that oleic acid (51.77 ± 0.67%) and palmitic acid (37.22 ± 0.48%) were major components. The synthesis variable factors of 50 °C, 45 h reaction time, and 1400 U of CPL were predicted by the RSM to be optimum conditions and thus provided the highest glucose palm oleate of 0.3542 mmol/g. Conjugation between palm olein fatty acids and glucose via transesterification resulted in glucose palm oleate being obviously verified by UPLC, Fourier-transform infrared spectroscopy (FTIR), and thin-layer chromatography (TLC) analyses. The synthesized sugar fatty acid ester revealed an HLB value of 6.20 represented by the lowest % creaming index (%CI) of 35.40 ± 3.21%. It also exhibited a critical micelle concentration (CMC) of 3.16 × 10−5 M. This study is the first report to reveal the transesterification of glucose and palm olein catalyzed by CPL in a system without using any solvent. Glucose palm oleate has been shown to be derived from an environmentally friendly synthesis process and would be promising as a potential alternative natural surfactant for cosmetic application.

Enzymatic Synthesis and Molecular Modelling Studies of Rhamnose Esters Using Lipase from Pseudomonas stutzeri

Rhamnolipids are becoming an important class of glycolipid biosurfactants. Herein, we describe for the first time the enzymatic synthesis of rhamnose fatty acid esters by the transesterification of rhamnose with fatty acid vinyl esters, using lipase from Pseudomonas stutzeri as a biocatalyst. The use of this lipase allows excellent catalytic activity in the synthesis of 4-O-acylrhamnose (99% conversion and full regioselectivity) after 3 h of reaction using tetrahydrofuran (THF) as the reaction media and an excess of vinyl laurate as the acyl donor. The role of reaction conditions, such as temperature, the substrates molar ratio, organic reaction medium and acyl donor chain-length, was studied. Optimum conditions were found using 35 °C, a molar ratio of 1:3 (rhamnose:acyldonor), solvents with a low logP value, and fatty acids with chain lengths from C4 to C18 as acyl donors. In hydrophilic solvents such as THF and acetone, conversions of up to 99–92% were achieved after 3 h of reaction. In a more sustainable solvent such as 2-methyl-THF (2-MeTHF), high conversions were also obtained (86%). Short and medium chain acyl donors (C4–C10) allowed maximum conversions after 3 h, and long chain acyl donors (C12–C18) required longer reactions (5 h) to get 99% conversions. Furthermore, scaled up reactions are feasible without losing catalytic action and regioselectivity. In order to explain enzyme regioselectivity and its ability to accommodate ester chains of different lengths, homology modelling, docking studies and molecular dynamic simulations were performed to explain the behaviour observed.

Lipozyme 435-Mediated Synthesis of Xylose Oleate in Methyl Ethyl Ketone

In this paper, we have performed the Lipozyme 435-catalyzed synthesis of xylose oleate in methyl ethyl ketone (MEK) from xylose and oleic acid. The effects of substrates’ molar ratios, reaction temperature, reaction time on esterification rates, and Lipozyme 435 reuse were studied. Results showed that an excess of oleic acid (xylose: oleic acid molar ratio of 1:5) significantly favored the reaction, yielding 98% of xylose conversion and 31% oleic acid conversion after 24 h-reaction (mainly to xylose mono- and dioleate, as confirmed by mass spectrometry). The highest Lipozyme 435 activities occurred between 55 and 70 °C. The predicted Ping Pong Bi Bi kinetic model fitted very well to the experimental data and there was no evidence of inhibitions in the range assessed. The reaction product was purified and presented an emulsion capacity close to that of a commercial sugar ester detergent. Finally, the repeated use of Lipozyme 435 showed a reduction in the reaction yields (by 48 and 19% in the xylose and oleic acid conversions, respectively), after ten 12 h-cycles.

Reviewing research on the synthesis of CALB-catalyzed sugar esters incorporating systematic mapping principles

Rigorous evidence reviews must follow specific guidelines designed to improve transparency, reproducibility, and to minimize biases to which traditional reviews are susceptible. While evidence synthesis methods, such as systematic reviews and maps, have been used in several research fields, the majority of reviews published in the realm of chemical engineering are nonsystematic. In this study, we incorporated principles of systematic mapping to conduct a literature review covering research on the synthesis of sugar fatty acid esters (SFAE) with Candida antarctica lipase B (CALB). Our results showed that the simple monosaccharides were the most cited sugars among studies we conducted. The direct use of renewable raw materials and frequently available resources to produce alternative sugar esters (SE) was scarcely reported in our data set. We found that free fatty acids (FFA) were the most commonly cited acyl donors amongst all publications, with lauric, oleic, and palmitic acids accounting for ∼43% of the occurrences. Tertiary alcohols (ter-butyl alcohol (T-but) and 2-methyl-2-butanol (2M2B)) and ionic liquids were the most used solvents to synthesize SE. The co-occurence analysis of keywords involving solvent terms showed that most of the papers evaluated different solvents as reaction media (mostly in the form of a bisolvent system), also investigating the impact of their choice on sugar ester productivities. Given the potential of reviews informing us of research decisions, this article reveals trends and spaces across CALB-catalyzed SE synthesis research, in addition to introducing a new methodological perspective for developing reviews in the field of chemical engineering.

Lipase-catalysed synthesis of mono- and di-acyl esters of glyceryl caffeate in propylene carbonate and their antioxidant properties in tuna oil

Development of new non-toxic antioxidants with diverse hydrophobic properties is important due to growing concerns about the toxicity of artificial oil-soluble antioxidants, the comparatively low effectiveness of natural options, and the complex role hydrophobicity plays in antioxidant effectiveness. Using caffeic acid, a naturally occurring phenolic acid with potent antioxidant activity, a range of glyceryl caffeate esters (decanoate and palmitate) were prepared using lipase-catalysed esterification reactions. Glyceryl-1-caffeate (GC) was prepared from ethyl caffeate and glycerol (acting as both the solvent and the substrate), catalysed by immobilised Candida Antarctica lipase B (Novozym-435) at 80 °C under vacuum. Esterification of GC with decanoic acid using immobilised Thermomyces lanuginosus lipase (TLIM) or Novozym-435 was found to be selective towards mono-acylated or di-acylated products, respectively. The reaction was performed in an unconventional solvent, propylene carbonate (PC), which has many of the attributes of a green solvent. Product conversions in PC were comparable to the best performing conventional solvents. In contrast to conventional volatile solvents, the low volatility of PC allowed the reaction to be performed under vacuum, without the need for molecular sieves for removal of water produced during the reaction. Diisopropyl ether was effective at extracting the more lipophilic products from PC. Both the lipase (Novozym-435) and PC were reused four times with only a small loss in conversion efficiency. Glyceryl caffeate esters performed much better than α-tocopherol at protecting bulk tuna oil from oxidation (analysed using Rancimat). A comparison of glyceryl caffeate esters (decanoate/palmitate and mono-/di-acylated) showed that their antioxidant effectiveness in bulk tuna oil was not affected by chain-length, but compounds containing only one fatty ester were slightly more effective than those containing two fatty esters.

Novozym 435: the “perfect” lipase immobilized biocatalyst?

Novozym 435 (N435) is a commercially available immobilized lipase produced by Novozymes with its advantages and drawbacks.

Enhanced Ricinoleic Acid Preparation Using Lipozyme TLIM as a Novel Biocatalyst: Optimized by Response Surface Methodology

Ricinoleic acid (RA) is an important raw material for plasticizers, emulsifiers, and nanomaterials. In this work, a green and efficient method was developed for RA production. Results showed that Lipozyme TLIM can be used as a novel biocatalyst to catalyze the hydrolysis of castor oil (CO) for RA preparation. Response surface methodology (RSM) was used to evaluate and optimize the effects of reaction variables on the hydrolysis of CO. Reaction conditions were optimized as follows: 41.3 °C, enzyme load 8.9%, 39.2 h, and 40:1 molar ratio of water to oil. Under these optimized reaction variables, the maximum hydrolysis ratio of CO (96.2 ± 1.5%) was obtained. The effect of hydrolysis variables on the reaction was as follows: enzyme load > hydrolysis time > temperature. In conclusion, this is a green, simple, and efficient method for RA preparation and can provide a good alternative method for RA industrial production.