RESUMO
Monoterpenes, such as beta-pinene, are secondary metabolites widely used in the flavors and fragrance industries and can have their structure altered to enhance their applicability, such as producing epoxides, which are used as intermediaries for pharmaceuticals. Epoxides are commonly synthesized by the use of inorganic acids as catalysts, although the acid medium induces epoxide degradation. To overcome these limitations biocatalysis is shown as an alternative. Related to, this work aimed to perform the synthesis of ß-Pinene epoxide using Pseudozyma antarctica lipase B (Novozym®435) as a biocatalyst, while determining the independent variables that influence the reaction using experimental design tools. Different solvent systems were evaluated (cyclohexane, acetonitrile, ethyl acetate, and dichloromethane) until 72 h reaction time, from which ethyl acetate showed higher conversion into the epoxidized product (40% in 24 h). Under the other solvents systems, several oxidized by-products were obtained, such as ketones and aldehydes. Moreover, applying metrics of green chemistry, ethyl acetate was also corroborated as the most promising solvent, with a higher atom economy (66.8%) in comparison to the others (41.3%), and a smaller E-value (1.19). Ethyl acetate was the solvent/acyl donor of choice and had the molar ratio and percentage of biocatalyst increased, which resulted in 80% of the product after 3 h of reaction. To obtain an optimized model, four independent variables (temperature, stirring, molar ratio, percentage of biocatalyst) were evaluated using experimental design tools, Fractional Factorial Design and Central Composite Rotatable Design, with conversions ranging from 23 to 95% after 3 h. All the independent variables were statistically significant (p < 0.05) and had different degrees of impact on the conversion. Kinetic parameters of the reaction were determined using the Lineweaver-Burk model (results under 30.1 mmol for Km and 10.7 mmol.min-1 for Vmax). In conclusion, the combination of two different tools of experimental design provided the development of an optimized model for beta-Pinene epoxidation, achieving high conversion to the epoxidized product after 3 h.
Assuntos
Enzimas Imobilizadas , Compostos de Epóxi , Monoterpenos Bicíclicos , Biocatálise , Enzimas Imobilizadas/metabolismo , Solventes/químicaRESUMO
OBJECTIVE: The present report describes the enzymatic acylation of umbelliferone with different vinyl esters as acyl donors biocatalyzed by the commercial lipase Novozym® 435, and the investigation for their antibacterial activity against ATCC and clinical strains isolated from hospital infection sites. RESULTS: The umbelliferone esters (1-5) were synthesized through the acylation reaction of 7-hydroxy-2H-chromen-2-one with different long chain vinyl esters catalyzed by the lipase Novozym 435. The reaction conditions were: 10% Novozym 435; tetrahydrofuran:acetone (3:1) for the reactions with acetate, propionate and butyrate vinyl esters 50-90% conversion, and (9:1) for decanoate and laurate vinyl esters 10-15% conversion; acyl donor/umbelliferone molar ratio of 10:1 and 60 °C. All the umbelliferone esters were characterized NMR and (HRMS). The antibacterial activity of the products were tested using the broth microdilution method in order to determine the minimum inhibitory concentration (MIC). The results displayed by 7-laurate and 7-decanoate-umbelliferone esters showed the highest antibacterial potential, with 1 mM inhibitory activity for ATCC 33591, a methicillin and oxacillin resistant Staphylococcus aureus strain. They were also able to inhibit gram-negative bacterial strains, such as Pseudomonas aeruginosa (MIC 0.5 mM) and Klebsiella pneumoniae (MIC 1 mM). In addition, 7-laurate- and 7-decanoate-umbelliferone esters were able to inhibit all clinical strains (MIC 1 mM; except 7-laurate-umbelliferone in which MIC 0.5 mM against 55a). CONCLUSIONS: This is the first study performing the biocatalysis of umbelliferone followed by the purification of the products and the antibacterial evaluation.
Assuntos
Infecções Bacterianas/tratamento farmacológico , Ésteres/farmacologia , Lipase/química , Umbeliferonas/farmacologia , Antibacterianos/síntese química , Antibacterianos/farmacologia , Infecções Bacterianas/microbiologia , Biocatálise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/genética , Ésteres/síntese química , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Humanos , Klebsiella pneumoniae/efeitos dos fármacos , Klebsiella pneumoniae/patogenicidade , Lipase/genética , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/patogenicidade , Transdução de Sinais/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/patogenicidade , Umbeliferonas/síntese químicaRESUMO
The total or partial substitution of fossil raw materials by biobased materials from renewable resources is one of the great challenges of our society. In this context, the reaction under mild condition as enzyme-catalyzed esterification was applied to investigate the esterification of the biobased 10-undecenoic acid with 2-hydroxyethyl methacrylate (HEMA) to obtain a new diene ester monomer. The environmentally friendly enzymatic reaction presented up to 100% of conversion; moreover, the production of possible by-products was minimized controlling reaction time and amount of enzyme. Furthermore, the presence of chloroform was evaluated during the enzymatic reactions and despite high conversions with higher enzyme concentration, the solvent-free system showed fast kinetics even with 1.13 U/g substrates. In addition, the commercial immobilized lipases Novozym 435 and NS 88011 could be applied for up to 10 cycles keeping conversions about 90%. The scale-up of the reaction was possible and a purification procedure was applied in order to isolate the diene ester monomer 2-(10-undecenoyloxy)ethyl methacrylate, preserving its double bonds, which could allow a potential use of this product in the synthesis of new renewable polymers through techniques as metathesis, thiol-ene, or free-radical polymerization.
Assuntos
Ésteres/química , Ésteres/síntese química , Proteínas Fúngicas/metabolismo , Lipase/metabolismo , Ácidos Undecilênicos/química , Biocatálise , Técnicas de Química Sintética , Esterificação , Química Verde , Cinética , Metacrilatos/químicaRESUMO
The effects of the reaction medium and substrate concentration were studied on the selectivity of Novozym 435 using the asymmetric hydrolysis of dimethyl-3-phenylglutarate as a model reaction. Results show that the use of choline chloride ChCl:urea/phosphate buffer 50% (v/v) as a reaction medium increased the selectivity of Novozym 435 by 16% (e.e = 88%) with respect to the one in 100% phosphate buffer (e.e = 76%). Best results were obtained when high substrate concentrations (well above the solubility limit, 27-fold) and ChCl:urea/phosphate buffer 50% (v/v) as reaction medium at pH 7 and 30 °C were used. Under such conditions, the R-monoester was produced with an enantiomeric purity of 99%. Novozym 435 was more stable in ChCl:urea/phosphate buffer 50% (v/v) than in phosphate buffer, retaining a 50% of its initial activity after 27 h of incubation at pH 7 and 40 °C. Results suggest that the use of deep eutectic solvents (ChCl:urea/phosphate buffer) in an heterogeneous reaction system (high substrate concentration) is a viable and promising strategy for the synthesis of chiral drugs from highly hydrophobic substrates.
Assuntos
Colina/química , Glutaratos/química , Lipase/metabolismo , Solventes/química , Enzimas Imobilizadas , Proteínas Fúngicas , Concentração de Íons de Hidrogênio , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Estereoisomerismo , Especificidade por Substrato , TemperaturaRESUMO
The demand for environmentally friendly products allied with the depletion of natural resources has increased the search for sustainable materials in chemical and pharmaceutical industries. Polyesters are among the most widely used biodegradable polymers in biomedical applications. In this work, aliphatic polyesters (from globalide and ω-pentadecalactone) were synthesized using a new commercial biocatalyst, the low-cost immobilized NS 88011 lipase (lipase B from Candida antarctica immobilized on a hydrophobic support). Results were compared with those obtained under the same conditions using a traditional, but more expensive, commercial biocatalyst, Novozym 435 (lipase B from C. antarctica immobilized on Lewatit VP OC). When NS 88011 was used in the polymerization of globalide, longer reaction times (240 min)-when compared to Novozym 435-were required to obtain high yields (80-90 wt%). However, higher molecular weights were achieved. When poly(ω-pentadecalactone) was synthesized, high yields and molecular weights (130,000 g mol-1) were obtained and the enzyme concentration showed strong influence on the polyester properties. This is the first report describing NS 88011 in polymer synthesis. The use of this cheaper enzymatic preparation can provide an alternative for polyester synthesis via enzymatic ring-opening polymerization.
Assuntos
Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Lipase/química , Poliésteres , Catálise , Poliésteres/síntese química , Poliésteres/químicaRESUMO
Abstract The production of compounds via enzymatic esterification has great scientific and technological interest due to the several inconveniences related to acid catalysis, mainly by these systems do not fit to the concept of “green chemistry”. Besides, natural products as clove oil present compounds with excellent biological potential. Bioactives compounds are often toxic at high doses. The evaluation of lethality in a less complex animal organism can be used to a monitoring simple and rapid, helping the identification of compounds with potential insecticide activity against larvae of insect vector of diseases. In this sense, the toxicity against Artemia salina of clove essential oil and its derivative eugenyl acetate obtained by enzymatic esterification using Novozym 435 as biocatalyst was evaluated. The conversion of eugenyl acetate synthesis was 95.6%. The results about the evaluation of toxicity against the microcrustacean Artemia salina demonstrated that both oil (LC50= 0.5993 µg.mL–1) and ester (LC50= 0.1178 µg.mL–1) presented high toxic potential, being the eugenyl acetate almost 5 times more toxic than clove essential oil. The results reported here shows the potential of employing clove oil and eugenyl acetate in insecticide formulations.
Resumo A produção de compostos via esterificação enzimática possui grande interesse científico e tecnológico devido às inúmeras inconveniências relacionadas com a catálise ácida, principalmente por estes sitemas não se adequarem ao atual termo “tecnologias limpas”. Além disso, produtos naturais como o óleo de cravo, apresentam compostos com excelentes potenciais biológicos. Compostos bioativos são quase sempre tóxicos em altas doses. A avaliação da letalidade em um organismo animal menos complexo pode ser usada para um monitoramento simples e rápido, servindo também para a identificação de compostos com potencial atividade inseticida contra larvas de insetos vetores de doenças. Neste sentido, foi determinada a toxicidade frente a Artemia salina do óleo essencial de cravo e do seu derivado acetato de eugenila obtido por esterificação enzimática com lipase Novozym 435. A conversão da reação de síntese de acetato de eugenila foi de 95,6%. Os resultados referentes à avaliação da toxicidade frente ao microcrustáceo Artemia salina demonstraram que tanto o óleo (LC50= 0,5993 µg.mL–1) quanto o éster (LC50= 0,1178 µg.mL–1) apresentam elevado potencial toxicológico, sendo que o éster apresenta aproximadamente 5 vezes mais toxicidade em relação ao óleo. Estes resultados demonstram o potencial emprego do óleo de cravo e de acetato de eugenila em formulações de inseticidas.
Assuntos
Animais , Artemia/efeitos dos fármacos , Óleos Voláteis/toxicidade , Óleo de Cravo/toxicidade , Inseticidas/toxicidade , Eugenol/análogos & derivados , Eugenol/síntese química , Eugenol/toxicidade , Relação Dose-Resposta a Droga , Esterificação/efeitos dos fármacos , Larva/efeitos dos fármacos , Lipase/toxicidadeRESUMO
The production of compounds via enzymatic esterification has great scientific and technological interest due to the several inconveniences related to acid catalysis, mainly by these systems do not fit to the concept of green chemistry. Besides, natural products as clove oil present compounds with excellent biological potential. Bioactives compounds are often toxic at high doses. The evaluation of lethality in a less complex animal organism can be used to a monitoring simple and rapid, helping the identification of compounds with potential insecticide activity against larvae of insect vector of diseases. In this sense, the toxicity against Artemia salina of clove essential oil and its derivative eugenyl acetate obtained by enzymatic esterification using Novozym 435 as biocatalyst was evaluated. The conversion of eugenyl acetate synthesis was 95.6%. The results about the evaluation of toxicity against the microcrustacean Artemia salina demonstrated that both oil (LC50= 0.5993 µg.mL1) and ester (LC50= 0.1178 µg.mL1) presented high toxic potential, being the eugenyl acetate almost 5 times more toxic than clove essential oil. The results reported here shows the potential of employing clove oil and eugenyl acetate in insecticide formulations.(AU)
A produção de compostos via esterificação enzimática possui grande interesse científico e tecnológico devido às inúmeras inconveniências relacionadas com a catálise ácida, principalmente por estes sitemas não se adequarem ao atual termo tecnologias limpas. Além disso, produtos naturais como o óleo de cravo, apresentam compostos com excelentes potenciais biológicos. Compostos bioativos são quase sempre tóxicos em altas doses. A avaliação da letalidade em um organismo animal menos complexo pode ser usada para um monitoramento simples e rápido, servindo também para a identificação de compostos com potencial atividade inseticida contra larvas de insetos vetores de doenças. Neste sentido, foi determinada a toxicidade frente a Artemia salina do óleo essencial de cravo e do seu derivado acetato de eugenila obtido por esterificação enzimática com lipase Novozym 435. A conversão da reação de síntese de acetato de eugenila foi de 95,6%. Os resultados referentes à avaliação da toxicidade frente ao microcrustáceo Artemia salina demonstraram que tanto o óleo (LC50= 0,5993 µg.mL1) quanto o éster (LC50= 0,1178 µg.mL1) apresentam elevado potencial toxicológico, sendo que o éster apresenta aproximadamente 5 vezes mais toxicidade em relação ao óleo. Estes resultados demonstram o potencial emprego do óleo de cravo e de acetato de eugenila em formulações de inseticidas.(AU)
Assuntos
Óleo de Cravo/toxicidade , Esterificação , Artemia , Ensaios EnzimáticosRESUMO
The objective of this study is to evaluate the batch enzymatic production of biodiesel in solvent-free system under ultrasound using as substrates ethanol, soybean oil and macauba fruit oil. For this purpose, a Plackett & Burman experimental design was carried out for soybean oil while a 24-1 design was conducted for macauba oil in order to maximize the biodiesel conversion for each system. Good conversions to fatty acid ethyl esters (FAEE), 88% for soybean oil and 75.2% for macauba oil, was obtained thus demonstrating the potential use of ultrasound for this reaction system.
Assuntos
Arecaceae/química , Biocombustíveis , Biotecnologia/métodos , Lipase/metabolismo , Óleo de Soja/metabolismo , Ondas Ultrassônicas , Biocatálise , Enzimas Imobilizadas , Esterificação , Proteínas Fúngicas , CinéticaRESUMO
In this work, the ethanolysis of triglycerides catalyzed by immobilized lipase was studied, focusing on the secondary reaction of acyl migration. The catalytic tests were performed in a solvent-free reaction medium using Novozym 435 as biocatalyst. The selected experimental variables were biocatalyst loading (5-20mg), reaction time (30-90min), and chain length of the fatty acids in triglycerides with and without unsaturation (short (triacetin), medium (tricaprylin) and long (tripalmitin/triolein)). The formation of 2-monoglyceride by ethanolysis of triglycerides was favored by long reaction times and large biocatalyst loading with saturated short- to medium-chain triglycerides. In the case of long-chain triglycerides, the formation of this monoglyceride was widely limited by acyl migration. In turn, acyl migration increased the yield of ethyl esters and minimized the content of monoglycerides and diglycerides. Thus, the enzymatic synthesis of biodiesel was favored by long-chain triglycerides (which favor the acyl migration), long reaction times and large biocatalyst loading. The conversion of acylglycerides made from long-chain fatty acids with unsaturation was relatively low due to limitations in their access to the active site of the lipase.
Assuntos
Lipase/química , Lipase/metabolismo , Modelos Químicos , Triglicerídeos/síntese química , Biocombustíveis , Cromatografia Gasosa/métodos , Diglicerídeos/síntese química , Diglicerídeos/química , Enzimas/química , Enzimas Imobilizadas/química , Ésteres/síntese química , Etil-Éteres/síntese química , Etil-Éteres/química , Gorduras Insaturadas/síntese química , Gorduras Insaturadas/química , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Proteínas Fúngicas , Glicerol/síntese química , Glicerol/química , Cinética , Monoglicerídeos/síntese química , Monoglicerídeos/química , Solventes/química , Triglicerídeos/químicaRESUMO
3 beta-O-phthalic ester of betulinic acid was synthesized from reaction of betulinic acid and phthalic anhydride using lipase as biocatalyst. This ester has clinical potential as an anticancer agent. In this study, artificial neural network (ANN) analysis of Candida antarctica lipase (Novozym 435) -catalyzed esterification of betulinic acid with phthalic anhydride was carried out. A multilayer feed-forward neural network trained with an error back-propagation algorithm was incorporated for developing a predictive model. The input parameters of the model are reaction time, reaction temperature, enzyme amount and substrate molar ratio while the percentage isolated yield of ester is the output. Four different training algorithms, belonging to two classes, namely gradient descent and Levenberg-Marquardt (LM), were used to train ANN. The paper makes a robust comparison of the performances of the above four algorithms employing standard statistical indices. The results showed that the quick propagation algorithm (QP) with 4-9-1 arrangement gave the best performances. The root mean squared error (RMSE), coefficient of determination (R²) and absolute average deviation (AAD) between the actual and predicted yields were determined as 0.0335, 0.9999 and 0.0647 for training set, 0.6279, 0.9961 and 1.4478 for testing set and 0.6626, 0.9488 and 1.0205 for validation set using quick propagation algorithm (QP).