Fatty Acid Epoxides Research Articles

Lipase catalyzed green epoxidation of oleic acid using ultrasound as a process intensification method

Epoxidized fatty acids are important green intermediates for chemical industry. This work was focused on the direct epoxidation of oleic acid (OA) using immobilized lipase Novozym® 435 as the catalyst and hydrogen peroxide (HP) as the epoxidation agent. The impacts of reactant molar ratio (HP:OA = 1…2), reaction temperature (30–60 °C), catalyst loading (7 wt-%) and stirring rate (500–1000 rpm) on the fatty acid conversion and epoxide selectivity were evaluated Acoustic irradiation and an advanced stirring system were implemented for reaction intensification and different ultrasound amplitudes (0–90%) were screened. Novozym® 435 revealed to be an efficient and durable catalyst for fatty acid epoxidation. The reaction was promoted by an excess of HP. The highest epoxide selectivity was about 80% at full conversion of oleic acid reached within 200 min. Ultrasound irradiation (90% amplitude) enhanced the initial reaction rate by a factor two compared to silent conditions and higher oleic acid conversions were reached compared to silent experiments. The catalyst preserved its activity and selectivity rather well, which was confirmed by catalyst recovery experiments conducted in the absence and presence acoustic irradiation. The main ring-opening agent is the fatty acid itself, which resulted in the formation of esters.

A new perspective on vegetable oil epoxidation modeling: Reaction and mass transfer in a liquid–liquid–solid system

AbstractA rigorous mathematical model was developed for a complex liquid–liquid–solid system in a batch reactor. The approach is general but well applicable for the indirect epoxidation of vegetable oils according to the concept of Nikolaj Prileschajew, implying in situ prepared percarboxylic acids as epoxidation agents. The model considers intra‐ and interfacial mass transfer effects coupled to reaction kinetics. The liquid phases were described with chemical approach (aqueous phase) and a reaction–diffusion approach (oil phase). The oil droplets were treated as rigid spheres, in which the overall reaction rate is influenced by chemical reactions and molecular diffusion. The model was tested with a generic example, where two reactions proceeded simultaneously in the aqueous and oil phases. The example (i.e., fatty acid epoxidation) illustrated the power of real multiphase model in epoxidation processes. The proposed modeling concept can be used for optimization purposes for applications, which comprise a complex water–oil–solid catalyst system.

Fatty acid epoxides in the regulation of the inflammation

Cyclooxygenase and lipoxygenase derived lipid metabolites of polyunsaturated fatty acids (PUFAs), as well as their role in the inflammation, have been studied quite thoroughly. However, cytochrome P450 derived lipid mediators, as well as their participation in the regulation of the inflammation, need deeper understanding. In recent years, it has become known that PUFAs are oxidized by cytochrome P450 epoxygenases to epoxy fatty acids, which act as the extremely powerful lipid mediators involved in resolving inflammation. Recent studies have shown that the anti-inflammatory mechanisms of ω-3 PUFAs are also mediated by their conversion to the endocannabinoid epoxides. Thus, it is clear that a number of therapeutically relevant functions of PUFAs are due to their conversion to PUFA epoxides. However, with the participation of cytochrome P450 epoxygenases, not only PUFA epoxides, but also other metabolites are formed. They are further are converted by epoxide hydrolases into pro-inflammatory dihydroxy fatty acids and anti-inflammatory dihydroxyeicosatrienoic acids. The study of the role of PUFA epoxides in the regulation of the inflammation and pharmacological modeling of the activity of epoxide hydrolases are the promising strategies for the treatment of the inflammatory diseases. This review systematizes the current literature data of the fatty acid epoxides, in particular, the endocannabinoid epoxides. Their role in the regulation of inflammation is discussed.

Serum oxylipins indicate subcortical ischemic vascular disease in patients with clinical stroke

AbstractBackgroundSubcortical ischemic vascular disease (SIVD) is the most common vascular pathology found in patients with late onset dementia. The soluble epoxide hydrolase (sEH) enzyme inactivates anti‐inflammatory and vasoactive cytochrome p450 derived polyunsaturated fatty acid epoxides by converting them into cytotoxic dihydroxy (diol) oxylipin species. Previously, we found that the ratios of linoleic acid (LA) diols to epoxides were associated with more white matter hyperintensity (WMH) in patients with transient ischemic attack; however, it remains univestigated if these oxylipins can identify SIVD in patients with ischemic stroke of heterogenous cerebrovascular pathologies such as large vessel occlusion and lacunar infarcts.MethodThe study cohort comprises patients from the Ontario Neurodegenerative Disease Research Initiative, who has clinical stroke of either large or small vessel etiology (according to TOAST criteria). 4 LA oxylipins (12,13‐dihydroxyoctadecamonoenoic acid (12,13‐DiHOME), 12,13‐epoxyoctadecenoic acid (12,13‐EpOME), 9,10‐DiHOME, 9,10‐EpOME) were extracted from blood and quantified with a targeted ultrahigh pressure liquid chromatography mass spectrometry (UPLC‐MS/MS) WMH and perivascular spaces (PVS) were quantified from structural MRI scans using a personalized semi‐automatic processing pipeline (Lesion Explorer). The associations between oxylipins and small vessel disease markers were examined using linear regression models.ResultIn 80 stroke patients (n=50 large vessel disease and n=30 lacunar infarcts), the ratio of 12,13‐DiHOME to its epoxide sEH substrate 12,13‐EpOME was higher among patients with small vessel etiology (F1,79 = 4.55, p = 0.036). In linear regression models controlling for age, sex, APOE, waist hip ratio, diabetes, and hyperlipidemia, the same ratio, and the ratio of 9,10‐DiHOME/9,10‐EpOME were positively associated with volume of deep (β = 0.338, p = 0.004; β = 0.288, p = 0.012, respectively) and periventricular (β = 0.316, p = 0.003; β = 0.400, p < 0.001, respectively) WMH. The same ratios were associated with higher volumes of perivascular spaces in the white matter (β = 0.293, p = 0.013; β = 0.276, p = 0.016, respectively) but not in the basal ganglia (β = 0.145, p = 0.212; β = 0.086, p = 0.450, respectively).ConclusionOxylipins derived from sEH activity may contribute to cerebral small vessel disease and to stroke of small vessel etiology.

Regioselective and Stereoselective Epoxidation of n-3 and n-6 Fatty Acids by Fungal Peroxygenases.

Epoxide metabolites from n-3 and n-6 polyunsaturated fatty acids arouse interest thanks to their physiological and pharmacological activities. Their chemical synthesis has significant drawbacks, and enzymes emerge as an alternative with potentially higher selectivity and greener nature. Conversion of eleven eicosanoid, docosanoid, and other n-3/n-6 fatty acids into mono-epoxides by fungal unspecific peroxygenases (UPOs) is investigated, with emphasis on the Agrocybe aegerita (AaeUPO) and Collariella virescens (rCviUPO) enzymes. GC-MS revealed the strict regioselectivity of the n-3 and n-6 reactions with AaeUPO and rCviUPO, respectively, yielding 91%-quantitative conversion into mono-epoxides at the last double bond. Then, six of these mono-epoxides were obtained at mg-scale, purified and further structurally characterized by 1H, 13C and HMBC NMR. Moreover, chiral HPLC showed that the n-3 epoxides were also formed (by AaeUPO) with total S/R enantioselectivity (ee > 99%) while the n-6 epoxides (from rCviUPO reactions) were formed in nearly racemic mixtures. The high regio- and enantioselectivity of several of these reactions unveils the synthetic utility of fungal peroxygenases in fatty acid epoxidation.

Bioavailability of Epoxidized Triglycerides in Seed Oil of <em>Alchornea cordifolia</em> (Schumach. & Thonn.) Müll. Arg. from Congo-Brazzaville

This study aims at the physico-chemical characterization of Alchornea cordifolia oil isolated from the seed of this plant, to identify the bioavailability of epoxidized triglycerides. The ripe fruits of Alchornea cordifolia were harvested in southern Congo-Brazzaville in the localities of Goma-tsetse and Dolisie. The oil is extracted from the seeds by three different methods: cold method (Folch), Soxhlet method, and water method. The fat contents are of the order of 18 to 28% by the water method, 30 to 37% by the Folch method and 45 to 56% by the Soxhlet method. All these methods exhibit similar fatty acid profiles. They are characterized by the presence of palmitic acids (C16: 0) 8 to 15%, stearic (C18: 0) 1 to 2%, oleic (C18: 1) 8 to 12%, linoleic (C18: 2) 8 to 12%, epoxidized fatty acid 48 to 63%, selacholeic (C24: 1) 2 to 3%. The epoxidized fatty acid contents are of the order of 50 to 63% by the water method, 50 to 61% by the Folch method and 48 to 58% by the Soxhlet method. The oil extracted with water has slightly higher epoxidized fatty acid contents than that extracted by other methods. The fatty acid composition of Alchornea cordifolia seed oil from Congo is characterized by high levels of epoxidized fatty acids in the order of 48-63%. This multi-functional acid has considerable commercial potential.

Mathematical modelling of oleic acid epoxidation via a chemo-enzymatic route – From reaction mechanisms to reactor model

The immobilized enzyme lipase acts as an efficient, selective and durable catalyst in the direct transformation of unsaturated carboxylic acids to epoxides, which are used as chemical intermediates and bio-lubricants. Experimental data obtained from the epoxidation of a model molecule, oleic acid in a laboratory-scale isothermal batch reactor were critically evaluated and mathematically modelled in the most precise way. Several rival surface reaction mechanisms were proposed and rate equations based on these mechanisms were derived. The rate equations were implemented in a multiphase model for the laboratory-scale batch reactor and the kinetic and adsorption parameters included in the rate equations were estimated with non-linear regression analysis. Based on the parameter estimation statistics and chemical knowledge, the most plausible kinetic models for the chemo-enzymatic epoxidation of oleic acid on the immobilized lipase catalyst were selected. The best kinetic models gave a good reproduction of the experimental data. The models can be used to predict the performance of enzymatic epoxidation of unsaturated fatty acids.

Kinetic study of the carbonation of epoxidized fatty acid methyl ester catalyzed over heterogeneous catalyst HBimCl‐NbCl5/HCMC

AbstractThe carbonation of epoxidized vegetable oils is a crucial step in the preparation of nonisocyanate polyurethane. Several research groups have screened homogeneous catalysts such as tetra‐n‐butylammonium bromide for this reaction, but the research devoted to the use of heterogeneous catalysts and on the application of kinetic modeling is rare. Hence, to develop this process on an industrial scale, an appropriate heterogeneous catalyst should be found and a kinetic model developed. A catalyst consisting of an ionic liquid supported on carboxymethyl cellulose has been proved to be a suitable heterogeneous catalyst for this carbonation reaction. A catalyst based on 1‐hydroxypropyl‐3‐n‐butylimidazolium chloride and niobium(V) chloride supported on protonated carboxymethyl cellulose (HBimCl‐NbCl5/HCMC) was synthesized and tested for the carbonation of epoxidized fatty acid methyl ester. Effects of the catalyst particle size, agitation speed, catalyst loading, and reaction temperature on the reaction kinetics were investigated. The carbonation reaction proceeded efficiently at a temperature of 443.15 K, agitation speed of 500 rpm, and using native catalyst particles with a median diameter of 652 μm. A kinetic model was developed to simulate the conversion of the epoxide group with time.

Differential Effects of Combined Soluble Epoxide Hydrolase Inhibitor t-TUCB and n-3 Epoxides in Diet-Induced Obesity

ObjectivesBrown adipose tissue (BAT) is a promising target for obesity prevention. N-3 epoxides are fatty acid epoxides produced from n-3 polyunsaturated fatty acids and shown to be beneficial for health. However, these epoxides are unstable and quickly metabolized by the cytosolic soluble epoxide hydrolase (sEH). Here, we investigated the effects of sEH inhibitor (t-TUCB) alone or combined with two different n-3 epoxides on BAT activation in the development of diet-induced obesity and associated metabolic disorders. MethodsMale C57BL6/J mice were fed a high-fat diet and received either of the following treatment: the vehicle control, t-TUCB alone (T), or t-TUCB combined with 19,20-EDP (T + EDP) or 17,18-EEQ (T + EEQ) via osmotic minipump delivery near the interscapular BAT for 6 weeks. Mice were examined for changes in body weight, food intake, glucose, insulin, and cold tolerance tests, and indirect calorimetry. Blood and tissue biochemical analyses were also performed to assess changes in metabolic homeostasis. ResultsAlthough no differences in food intake were observed, there were small but significant increases in body weight in both T and T + EDP groups. Mice in the T + EDP and T + EEQ groups showed significant decreases in fasting glucose and serum TG levels, higher core body temperature, and better cold tolerance compared to the controls. However, heat production was significantly increased only in the T + EEQ group. Thermogenic UCP1 protein expression showed a moderate, but not significant, increase in the T + EEQ group. On the other hand, PGC1 α protein expression was significantly increased in the T, T + EDP, and T + EEQ groups compared to the controls. Perilipin protein expression and phosphorylation were also significantly increased in the three treated groups. In contrast, protein expression of FABP4 and HSL was only increased in the T and T + EDP groups, and CD36 protein expression was only increased in the T + EEQ group. ConclusionsOur results suggest that sEH pharmacological inhibition by t-TUCB combined with n-3 epoxides may prevent high-fat diet-induced glucose and lipid disorders, in part through increased thermogenesis and upregulating of protein expression of thermogenic and lipid metabolic genes. Funding SourcesThe work was supported by NIH grants to L.Z., A.B., and B.D.H.

Local shifts in inflammatory and resolving lipid mediators in response to tendon overuse.

Tendon inflammation has been implicated in both adaptive connective tissue remodeling and overuse-induced tendinopathy. Lipid mediators control both the initiation and resolution of inflammation, but their roles within tendon are largely unknown. Here, we profiled local shifts in intratendinous lipid mediators via liquid chromatography-tandem mass spectrometry in response to synergist ablation-induced plantaris tendon overuse. Sixty-four individual lipid mediators were detected in homogenates of plantaris tendons from ambulatory control rats. This included many bioactive metabolites of the cyclooxygenase (COX), lipoxygenase (LOX), and epoxygenase (CYP) pathways. Synergist ablation induced a robust inflammatory response at day 3 post-surgery characterized by epitenon infiltration of polymorphonuclear leukocytes and monocytes/macrophages (MΦ), heightened expression of inflammation-related genes, and increased intratendinous concentrations of the pro-inflammatory eicosanoids thromboxane B2 and prostaglandin E2 . By day 7, MΦ became the predominant myeloid cell type in tendon and there were further delayed increases in other COX metabolites including prostaglandins D2 , F2α , and I2 . Specialized pro-resolving mediators including protectin D1, resolvin D2 and D6, as well as related pathway markers of D-resolvins (17-hydroxy-docosahexaenoic acid), E-resolvins (18-hydroxy-eicosapentaenoic acid), and lipoxins (15-hydroxy-eicosatetraenoic acid) were also increased locally in response to tendon overuse, as were anti-inflammatory fatty acid epoxides of the CYP pathway (eg, epoxy-eicosatrienoic acids). Nevertheless, intratendinous prostaglandins remained markedly increased even following 28 days of tendon overuse together with a lingering MΦ presence. These data reveal a delayed and prolonged local inflammatory response to tendon overuse characterized by an overwhelming predominance of pro-inflammatory eicosanoids and a relative lack of specialized pro-resolving lipid mediators.

Effects of the Molar Ratio of Acetic Acid to UFA and Stirring Velocity in the Tung Oil Epoxidation

Epoxidation of the unsaturated fatty acids (UFA) in Tung oil provides a very interesting opportunity in the research and development of advanced materials. Tung oil is one of non-edible vegetable oils and epoxidized Tung oil (ETO) also provides benefits in terms of renewable and eco-friendly. This research evaluated the influences of acetic acid's molar ratio to UFA and stirring velocity in the epoxidation process of Tung oil. Epoxidation was carried out in a batch reactor using peroxyacetic acid produced in-situ with sulfuric acid as a catalyst. This reaction was run at a temperature of 60 °C and the catalyst concentration of 1.5% (w) for 4 hours, with a periodic 30-minutes sampling time interval. The samples' analyses were iodine value (IV), conversion to oxirane, selectivity, and FTIR spectrometry. The results showed that both the molar ratio of acetic acid to UFA and stirring velocity were directly proportional to the conversion to oxirane, and inversely proportional to the IV. In contrast, the two process variables did not show a definite result that can be interpreted to the selectivity (very fluctuated). The highest conversion (about 57.43%) and the lowest IV (8.3898 g I2/100 g) were obtained at a 1:1 ratio for the reaction times of 150 and 240 minutes, respectively.

Biolubricant basestocks synthesis using 5-step reaction from jatropha oil, soybean oil, and palm fatty acid distillate

This research presents a 5-step chemical reaction and modifications to convert triglyceride of jatropha and soybean oils to biolubricant. Saponification and hydrolysis (1st), urea crystallization (2nd), epoxidation (3rd), epoxide ring opening (4th), and esterification (5th) were performed in a series. At first, jatropha and soybean oils were saponified and hydrolyzed, and unsaturated fatty acid (UFA) was separated. After hydrolysis, free fatty acid (FFA) of jatropha and soybean oils increased from 5.02 % and 0.00%–99.66% and 99.75 %, respectively. Next, UFA was successfully separated by urea crystallization, and UFA increased from 79.10%–97.98 % in jatropha oil and from 84.14%–99.64% in soybean oil. Palm fatty acid distillate (PFAD), a cheap co-product from palm oil factories, was used in the reaction to make branching molecules, and 1% (w/w) H2SO4 was the catalyst in esterification. All structure modifications were confirmed by GC-FID, 1H-NMR, and 13C-NMR, and the physical and chemical properties of the final products were analyzed. The confirmation of ≥90.09 % epoxidation was done by 1H-NMR. A 1.0:1.0 mol ratio of PFAD: epoxidized fatty acid (EFA) at 110 °C for the epoxide ring opening reaction and a 1.0:2.5 mol ratio of epoxide ring opening product (EROP):2-ethylhexanol (2-EtH) for the esterification were chosen, as this resulted in the highest conversion of ester products in both jatropha and soybean. The synthesized biolubricant basestocks appear to be suitable for a hydraulic fluid application, ISO 15380 in the HEES category.

CYP77B1 a fatty acid epoxygenase specific to flowering plants

Contrary to animals, little is known in plants about enzymes able to produce fatty acid epoxides. In our attempt to find and characterize a new fatty acid epoxygenase in Arabidopsis thaliana, data mining brought our attention on CYP77B1. Modification of the N-terminus was necessary to get enzymatic activity after heterologous expression in yeast. The common plant fatty acid C18:2 was converted into the diol 12,13-dihydroxy-octadec-cis-9-enoic acid when incubated with microsomes of yeast expressing modified CYP77B1 and AtEH1, a soluble epoxide hydrolase. This diol originated from the hydrolysis by AtEH1 of the epoxide 12,13-epoxy-octadec-cis-9-enoic acid produced by CYP77B1. A spatio-temporal study of CYP77B1 expression performed with RT-qPCR revealed the highest level of transcripts in flower bud while, in open flower, the enzyme was mainly present in pistil. CYP77B1 promoter-driven GUS expression confirmed reporter activities in pistil and also in stamens and petals. In silico co-regulation data led us to hypothesize that CYP77B1 could be involved in cutin synthesis but when flower cutin of loss-of-function mutants cyp77b1 was analyzed, no difference was found compared to cutin of wild type plants. Phylogenetic analysis showed that CYP77B1 is strictly conserved in flowering plants, suggesting a specific function in this lineage.

Efficient Synthesis of Cyclic Carbonates from Unsaturated Acids and Carbon Dioxide and their Application in the Synthesis of Biobased Polyurethanes.

Bio-derived furan- and diacid-derived cyclic carbonates have been synthesized in high yields from terminal epoxides and CO2 . Furthermore, four highly substituted terpene-derived cyclic carbonates were isolated in good yields with excellent diastereoselectivity in some cases. Eleven new cyclic carbonates derived from 10-undecenoic acid under mild reaction conditions were prepared, providing the corresponding carbonate products in excellent yields. The catalyst system also performed the conversion of an epoxidized fatty acid n-pentyl ester into a cyclic carbonate under relatively mild reaction conditions (80 °C, 20 bar, 24 h). This bis(cyclic carbonate) was obtained in high yields and with different cis/trans ratios depending on the co-catalyst used. An allyl alcohol by-product was only observed as a minor product when bis(triphenylphosphine)iminium chloride was used as co-catalyst. Finally, two cyclic carbonates were used as building blocks for the preparation of non-isocyanate poly(hydroxy)urethanes by reaction with 1,4-diaminobutane.

Movement to the Clinic of Soluble Epoxide Hydrolase Inhibitor EC5026 as an Analgesic for Neuropathic Pain and for Use as a Nonaddictive Opioid Alternative.

This report describes the development of an orally active analgesic that resolves inflammation and neuropathic pain without the addictive potential of opioids. EC5026 acts on the cytochrome P450 branch of the arachidonate cascade to stabilize epoxides of polyunsaturated fatty acids (EpFA), which are natural mediators that reduce pain, resolve inflammation, and maintain normal blood pressure. EC5026 is a slow-tight binding transition-state mimic that inhibits the soluble epoxide hydrolase (sEH) at picomolar concentrations. The sEH rapidly degrades EpFA; thus, inhibiting sEH increases EpFA in vivo and confers beneficial effects. This mechanism addresses disease states by shifting endoplasmic reticulum stress from promoting cellular senescence and inflammation toward cell survival and homeostasis. We describe the synthesis and optimization of EC5026 and its development through human Phase 1a trials with no drug-related adverse events. Additionally, we outline fundamental work leading to discovery of the analgesic and inflammation-resolving CYP450 branch of the arachidonate cascade.

Thermomorphic Polyethylene‐Supported Organocatalysts for the Valorization of Vegetable Oils and CO2

AbstractA range of thermomorphic polyethylene‐supported organocatalysts is prepared from N‐alkyl imidazoles and polyethylene iodide (PEI) with good yields (85–92%) and high funtionality (98–99%). The catalytic activity of these species is studied for the ring opening of epoxidized methyl oleate with CO2 to give the corresponding cyclic carbonate. The reaction is carried out at 100 °C to fully exploit the thermomorphic behavior of the organocatalysts. The optimized conditions (neat, 100 °C, and 20 bar of CO2) are applied to a range of epoxidized fatty acids, including an epoxidized rapeseed oil, to give the corresponding carbonates with good yields (75–96%). The catalyst recycling is also studied, and no significant loss of activity is observed after ten runs. The fatty carbonates are important intermediates for the preparation of non‐isocyanate polyurethanes (NIPUs).

Fatty-Acid Oxygenation by Fungal Peroxygenases: From Computational Simulations to Preparative Regio- and Stereoselective Epoxidation

Epoxidation of unsaturated fatty acids by unspecific peroxygenases (UPOs) of the best-known long-UPO subfamily, including the Agrocybe aegerita (AaeUPO) and Coprinopsis cinerea enzymes, is reported...

Kinetics Studies of Epoxidation and Oxirane Cleavage-Epoxidized Palm Kernel Oil

Background: Studies pertaining to the epoxidation of fatty acids, garnered much interest in recent years due to the rising demand of eco-friendly epoxides derived from vegetable oils. Methods: Epoxide is an important chemical precursor for the production of alcohols, glycols and polymers, like polyesters and epoxy resin. Epoxidation is the name given to the reaction when the double bonds are converted into epoxide. Results: Temperature at 55oC was used as a reference material in the epoxide process, as it produces a high yield epoxide being 88%. The kinetic rate of epoxidized palm kernel oil, k was obtained to be k11= 0.5125, k12= 0.05045, k21= 0.03185, k41= 0.01 and k51= 0.01243. Conclusion: Hence, by fitting the result with the experimental work and simulation, the summation of error being stimulated by I-sight simulation was 0.731116428 and the correlation between the experimental and simulation data was 0.925544.

Tall Oil Fatty Acid Epoxidation Using Homogenous and Heterogeneous Phase Catalysts

Tall oil fatty acids were epoxidized by in-situ generation of peracetic acid in the presence of two different acidic catalysts, commonly used catalyst—sulfuric acid and ion exchange resin. The described epoxidation was carried out without the use of organic solvents to comply with the principles of Green chemistry. The epoxidation process was monitored by the change of the relative oxirane conversion and alkenic unsaturation. Furthermore, the changes in the chemical structure of the epoxidized tall oil fatty acids were investigated using FTIR spectroscopy. It was shown that ion exchange resin Amberlite IR-120 H catalyst was superior to sulfuric acid catalyst as it delivered fewer by-products from oxirane group opening reactions. The oxirane value reached up to 2.31 mmol/g of epoxy groups, which is 41.9% of theoretically possible oxirane oxygen yield, when tall oil was epoxidized using Amberlite IR-120 H. The reusability of ion exchange resin was also studied, the 6.2% decrease in relative oxirane conversion value was registered after Amberlite IR-120 H was reused up to 10 times.

Correction: Fatty acid epoxidation by Collariella virescens peroxygenase and heme-channel variants

Correction for ‘Fatty acid epoxidation by Collariella virescens peroxygenase and heme-channel variants’ by Alejandro González-Benjumea et al., Catal. Sci. Technol., 2020, 10, 717–725.