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1.
Bioprocess Biosyst Eng ; 47(3): 313-323, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38438572

RESUMO

Molecular docking is an important computational analysis widely used to predict the interaction of enzymes with several starting materials for developing new valuable products from several starting materials, including oils and fats. In the present study, molecular docking was used as an efficient in silico screening tool to select biocatalysts with the highest catalytic performance in butyl esters production in a solvent-free system, an eco-friendly approach, via direct esterification of free fatty acids from Licuri oil with butanol. For such purpose, three commercial lipase preparations were used to perform molecular docking studies such as Burkholderia cepacia (BCL), Porcine pancreatic (PPL), and Candida rugosa (CRL). Concurrently, the results obtained in BCL and CRL are the most efficient in the esterification process due to their higher preference for catalyzing the esterification of lauric acid, the main fatty acid found in the licuri oil composition. Meanwhile, PPL was the least efficient because it preferentially interacts with minor fatty acids. Molecular docking with the experimental results indicated the better performance in the synthesis of esters was BCL. In conclusion, experimental results analysis shows higher enzymatic productivity in esterification reactions of 1294.83 µmol/h.mg, while the CRL and PPL demonstrated the lowest performance (189.87 µmol / h.mg and 23.96 µmol / h.mg, respectively). Thus, molecular docking and experimental results indicate that BCL is a more efficient lipase to produce fatty acids and esters from licuri oil with a high content of lauric acid. In addition, this study also demonstrates the application of molecular docking as an important tool for lipase screening to achieve more sustainable production of butyl esters with a view synthesis of biolubricants.


Assuntos
Ácidos Graxos , Lipase , Animais , Suínos , Lipase/química , Simulação de Acoplamento Molecular , Domínio Catalítico , Ácidos Graxos/química , Esterificação , Ésteres , Ácidos Láuricos , Enzimas Imobilizadas/metabolismo
2.
Molecules ; 29(3)2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38338371

RESUMO

This work presents a framework for evaluating hybrid nanoflowers using Burkholderia cepacia lipase. It was expanded on previous findings by testing lipase hybrid nanoflowers (hNF-lipase) formation over a wide range of pH values (5-9) and buffer concentrations (10-100 mM). The free enzyme activity was compared with that of hNF-lipase. The analysis, performed by molecular docking, described the effect of lipase interaction with copper ions. The morphological characterization of hNF-lipase was performed using scanning electron microscopy. Fourier Transform Infrared Spectroscopy performed the physical-chemical characterization. The results show that all hNF-lipase activity presented values higher than that of the free enzyme. Activity is higher at pH 7.4 and has the highest buffer concentration of 100 mM. Molecular docking analysis has been used to understand the effect of enzyme protonation on hNF-lipase formation and identify the main the main binding sites of the enzyme with copper ions. The hNF-lipase nanostructures show the shape of flowers in their micrographs from pH 6 to 8. The spectra of the nanoflowers present peaks typical of the amide regions I and II, current in lipase, and areas with P-O vibrations, confirming the presence of the phosphate group. Therefore, hNF-lipase is an efficient biocatalyst with increased catalytic activity, good nanostructure formation, and improved stability.


Assuntos
Cobre , Nanoestruturas , Estabilidade Enzimática , Cobre/química , Lipase/química , Simulação de Acoplamento Molecular , Nanoestruturas/química , Enzimas Imobilizadas/química , Espectroscopia de Infravermelho com Transformada de Fourier , Íons
3.
Molecules ; 27(24)2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36558047

RESUMO

The aim of this study was the development of a cereal bar based on bee pollen (BP), honey (H), and flour by-products (peel passion fruit flour-PPFF), generating an innovative product. BP is a protein-rich ingredient and can be used in the composition of cereal bars. PPFF is a by-product rich in fibers. The formulations were developed using a 23 factorial design with four replicates in the center point, studying the sensory analysis as a response variable. The texture and nutritional parameters were performed for the optimal formulation. BP showed ca. 15% of protein. The final formulation (10.35% BP, 6.8% PPFF, and 25% H) presented 22.2% moisture, 1.8% ash, 0.4% total fat, 3.0% fiber, 63.1% carbohydrates, and 74.0 Kcal/25 g. The sensory analysis presented valued around 7 (typical of a traditional bar). Regarding the possibility of purchasing the product, 51% of the panelists said they would probably buy the developed product. The formulated cereal bar had a similar composition as those already marketed. Moreover, it can be considered a source of fiber and is sensory acceptable. This approach opens up new opportunities for developing nutritional and functional foodstuff with improved sensorial aspects.


Assuntos
Fibras na Dieta , Mel , Fibras na Dieta/análise , Valor Nutritivo , Grão Comestível/química
4.
Bioprocess Biosyst Eng ; 45(7): 1149-1162, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35585433

RESUMO

Lipases (E.C. 3.1.1.3) have buried active sites and used access tunnels in the transport of substrates and products for biotransformation processes. Computational methods are used to predict the trajectory and energy profile of ligands through these tunnels, and they complement the experimental methodologies because they filter data, optimizing laboratory time and experimental costs. Access tunnels of Burkholderia cepacia lipase (BCL), Candida rugosa lipase (CRL), and porcine pancreas lipase (PPL) and the transport of fatty acids, alcohols and esters through the tunnels were evaluated using the online server CaverWeb V1.0, and server calculation results were compared with experimental data (productivity). BCL showed higher productivity with palmitic acid-C16:0 (4029.95 µmol/h mg); CRL obtained productivity for oleic acid-C18:1 (380.80 µmol/h mg), and PPL achieved productivity for lauric acid-C12:0 (71.27 µmol/h mg). The highest probability of transport for BCL is through the tunnels 1 and 2, for CRL through the tunnel 1, and for PPL through the tunnels 1, 2, 3 and 4. Thus, the best in silico result was the transport of the substrates palmitic acid and ethanol and product ethyl palmitate in tunnel 1 of BCL. This result corroborates with the best result for the productivity data (higher productivity for BCL with palmitic acid-4029.95 µmol/h mg). The combination of in silico evaluation and experimental data gave similar results, demonstrating that in silico approaches are a promising alternative for reducing screening tests and minimizing laboratory time in the bio-catalysis area by identifying the lipases with the greatest reaction potential, as in the case of this proposal.


Assuntos
Burkholderia cepacia , Lipase , Animais , Candida/metabolismo , Lipase/química , Ácido Oleico , Ácidos Palmíticos , Suínos
5.
Toxics ; 9(8)2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34437491

RESUMO

Multi-Walled Carbon Nanotubes (MWCNT) have been functionalized with rutin through three steps (i. reaction step; ii. purification step; iii. drying step) and their physicochemical properties investigated with respect to morphological structure, thermal analysis, Fourier Transform Infrared Spectroscopy (FTIR), and cytotoxicity. The molecular docking suggested the rutin-functionalized MWCNT occurred by hydrogen bonds, which was confirmed by FTIR assays, corroborating the results obtained by thermal analyses. A tubular shape, arranged in a three-dimensional structure, could be observed. Mild cytotoxicity observed in 3T3 fibroblasts suggested a dose-effect relationship after exposure. These findings suggest the formation of aggregates of filamentous structures on the cells favoring the cell penetration.

6.
Bioprocess Biosyst Eng ; 44(10): 2141-2151, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34037849

RESUMO

In the present study, we demonstrated the use of molecular docking as an efficient in silico screening tool for lipase-triglyceride interactions. Computational simulations using the crystal structures from Burkholderia cepacia lipase (BCL), Thermomyces lanuginosus lipase (TLL), and pancreatic porcine lipase (PPL) were performed to elucidate the catalytic behavior with the majority triglycerides present in Licuri oil, as follows: caprilyl-dilauryl-glycerol (CyLaLa), capryl-dilauryl-glycerol (CaLaLa), capryl-lauryl-myristoyl-glycerol (CaLaM), and dilauryl-myristoyl-glycerol (LaLaM). The computational simulation results showed that BCL has the potential to preferentially catalyze the major triglycerides present in Licuri oil, demonstrating that CyLaLa, (≈25.75% oil composition) interacts directly with two of the three amino acid residues in its catalytic triad (Ser87 and His286) with the lowest energy (-5.9 kcal/mol), while other triglycerides (CaLaLa, CaLaM, and LaLaM) interact with only one amino acid (His286). In one hard, TLL showed a preference for catalyzing the triglyceride CaLaLa also interacting with His286 residue, but, achieving higher binding energies (-5.3 kcal/mol) than found in BCL (-5.7 kcal/mol). On the other hand, PPL prefers to catalyze only with LaLaM triglyceride by His264 residue interaction. When comparing the computational simulations with the experimental results, it was possible to understand how BCL and TLL display more stable binding with the majority triglycerides present in the Licuri oil, achieving conversions of 50.86 and 49.01%, respectively. These results indicate the production of fatty acid concentrates from Licuri oil with high lauric acid content. Meanwhile, this study also demonstrates the application of molecular docking as an important tool for lipase screening to reach a more sustainable production of fatty acid concentrates from vegetable oils.


Assuntos
Arecaceae/química , Biologia Computacional/métodos , Lipase/metabolismo , Óleos de Plantas/química , Triglicerídeos/metabolismo , Animais , Burkholderia cepacia/enzimologia , Catálise , Eurotiales/enzimologia , Especificidade por Substrato , Suínos , Termodinâmica
7.
Biotechnol Appl Biochem ; 68(4): 801-808, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33180374

RESUMO

Guava seed biochar appears as a new alternative of the effective support to the immobilization of Burkholderia cepacia lipase (BCL) by physical adsorption. The objective of this work was to evaluate the potential of this immobilized biocatalyst in the transesterification reaction of crude coconut oil and ethanol and to understand the mechanism of the reaction through the study of molecular docking. The best loading of BCL was determined to be 0.15 genzyme /gsupport having a hydrolytic activity of 260 U/g and 54% immobilization yield. The products of transesterification reaction produced a maximum yield at 40 °C under different reaction conditions. The monoacylglycerols (MAGs) conversion of 59% was using substrate molar ratio oil:ethanol of 1:7 with the reaction time of 24 H. In addition, the highest ethyl esters yield (48%) had the molar ratio of 1:7 with the reaction time of 96 H and maximum conversion of diacylglycerols (DAGs) was 30% with the molar ratio of 1:6 with the reaction time of 24 H. Molecular Docking was applied to clarify the mechanisms of transesterification reaction at the molecular level. MAGs and DAGs are compounds with excellent emulsifying properties used in industrial production of several bioproducts such as cosmetic, pharmaceuticals, foods, and lubricants.


Assuntos
Proteínas de Bactérias/química , Burkholderia cepacia/enzimologia , Carvão Vegetal/química , Óleo de Coco/química , Enzimas Imobilizadas/química , Lipase/química , Esterificação
8.
Bioprocess Biosyst Eng ; 44(1): 195-208, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32892287

RESUMO

The use of microorganisms capable of mediating the bioprecipitation process can be an important application in the self-healing processes of cement specimens. Thus, the present study identified and evaluated five Bacillus strains for potential application in the protocol of self-healing via bioprecipitation. Cell growth, enzyme production, and kinetic parameters conditions were evaluated during the fermentation process. Based on the analysis of 16S rDNA in conjunction with biochemical testing, results demonstrate that the strains are either Bacillus cereus or Bacillus thuringiensis. Strategically it was found that the addition of glycerol to fermentative medium was essential to increase the bacterial concentration (≈ 4.2 × 107 cells mL-1) and production of the enzyme urease (≈ 3.623,2 U.mL-1). The addition of this medium after 40 days of fermentation promoted the self-healing of cracks and increased compressive strength in ≈ 14.2% of the cementitious specimens; therefore, increasing the sustainability and engineering properties of cement-based materials.


Assuntos
Bacillus cereus/crescimento & desenvolvimento , Bacillus thuringiensis/crescimento & desenvolvimento , Materiais de Construção
9.
Biotechnol Prog ; 37(1): e3064, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32776684

RESUMO

Bioimprinting is an easy, sustainable and low-cost technique that promotes a printing of potential substrates on enzyme structure, inducing a more selective and stable conformation. Bioimprinting promotes conformational changes in enzymes, resulting in better catalytic performance. In this work, the effect of bioimprinting of Burkholderia cepacia lipase (BCL) and porcine pancreatic extracts (PPE) with four different fatty acids (lauric acid (C12:0), myristic acid (C14:0), palmitic acid (C16:0), and stearic acid (C18:0)) was investigated. The results demonstrated that the better bioimprinting effect was in BCL with lauric acid in esterification reaction, promoting BCL activation in which relative enzyme activity was 70 times greater than nonimprinted BCL. Bioimprinting results were influenced by the carbon chain length of fatty acids imprinted in the BCL, in which the effects were weaker with the chain increase. Molecular docking was performed to better understand the bioimprinting method. The results of these simulations showed that indeed all fatty acids were imprinted in the active site of BCL. However, lauric acid presented the highest imprinting preference in the active site of BCL, resulting in the highest relative activity. Furthermore, Fourier transform infrared (FTIR) analysis confirmed important variations in secondary structure of bioimprinting BCL with lauric acid, in which there was a reduction in the α-helix content and an increase in the ß-sheet content that facilitated substrate access to the active site of BCL and led higher rigidity, resulting in high activity. Bioimprinted BCL with lauric acid showed excellent operational stability in esterification reaction, maintaining its original relative activity after five successive cycles. Thus, the results show that bioimprinting of BCL with lauric acid is a successful strategy due to its high catalytic activity and reusability.


Assuntos
Bioimpressão/instrumentação , Burkholderia cepacia/enzimologia , Ácidos Graxos/metabolismo , Lipase/metabolismo , Pâncreas/enzimologia , Animais , Bioimpressão/métodos , Domínio Catalítico , Esterificação , Lipase/química , Simulação de Acoplamento Molecular , Suínos
10.
Bioprocess Biosyst Eng ; 44(1): 57-66, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32767112

RESUMO

A new design of cross-linked enzyme aggregates (CLEAs) of Burkholderia cepacia lipase (BCL) based mainly on the use of lignocellulosic residue of palm fiber as an additive was proposed. Different parameters for the preparation of active CLEAs in the hydrolysis of olive oil, such as precipitation agents, crosslinking agent concentration, additives, and coating agents were investigated. The highest activity yield (121.1 ± 0.1%) and volumetric activity (1578.1 ± 2.5 U/mL) were achieved for CLEAs prepared using the combination of a coating step with Triton® X-100 and polyethyleneimine plus the use of palm fiber as an additive. The variations of the secondary structures of BCL-CLEAs were analyzed by second-derivative infrared spectra, mainly indicating a reduction of the α-helix structure, which was responsible for the lipase activation in the supramolecular structure of the CLEAs. Thus, these results provided evidence of an innovative design of BCL-CLEAs as a sustainable and biocompatible opportunity for biotechnology applications.


Assuntos
Proteínas de Bactérias/química , Burkholderia cepacia/enzimologia , Enzimas Imobilizadas/química , Lipase/química , Estabilidade Enzimática , Cinética
11.
Sci Rep ; 10(1): 14931, 2020 09 10.
Artigo em Inglês | MEDLINE | ID: mdl-32913223

RESUMO

Prostate specific antigen (PSA) is the most widely used clinical biomarker for the diagnosis and monitoring of prostate cancer. Most available techniques for PSA quantification in human fluids require extensive sample processing and expensive immunoassays that are often unavailable in developing countries. The quantification of PSA in serum is the most common practice; however, PSA is also present in human urine, although less used in diagnosis. Herein we demonstrate the use of ionic-liquid-based aqueous biphasic systems (IL-based ABS) as effective pre-treatment strategies of human urine, allowing the PSA detection and quantification by more expedite equipment in a non-invasive matrix. If properly designed, IL-based ABS afford the simultaneous extraction and concentration of PSA (at least up to 250-fold) in the IL-rich phase. The best ABS not only allow to concentrate PSA but also other forms of PSA, which can be additionally quantified, paving the way to their use in differential prostate cancer diagnosis.


Assuntos
Líquidos Iônicos , Antígeno Prostático Específico/urina , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/urina , Manejo de Espécimes/métodos , Urinálise/métodos , Diagnóstico Diferencial , Humanos , Masculino , Neoplasias da Próstata/classificação
12.
Biotechnol Appl Biochem ; 67(3): 404-413, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31930535

RESUMO

Here, we have assessed the use of one packed bed or two packed bed reactors in series in which Burkholderia cepacia lipase (BCL) was immobilized on protic ionic liquid (PIL)-modified silica and used as a biocatalyst for the transesterification of crude coconut oil. Reaction parameters including volumetric flow, temperature, and molar ratio were evaluated. The conversion of transesterification reaction products (ethyl esters) was determined using gas chromatography and the quantities of intermediate products (diglyceride and monoglyceride [MG]) were assessed using high-performance liquid chromatography. Packed bed reactors in series produced ethyl esters with the greatest efficiency, achieving 65.27% conversion after 96 H at a volumetric flow rate of 0.50 mL Min-1 at 40 °C and a 1:9 molar ratio of oil to ethanol. Further, within the first 24 H of the reaction, increased MG (54.5%) production was observed. Molecular docking analyses were performed to evaluate the catalytic step of coconut oil transesterification in the presence of BCL. Molecular docking analysis showed that triglycerides have a higher affinity energy (-5.7 kcal mol-1 ) than the smallest MG (-6.0 kcal mol-1 ), therefore, BCL catalyzes the conversion of triglycerides rather than MG, which is consistent with experimental results.


Assuntos
Reatores Biológicos , Óleo de Coco/metabolismo , Ésteres/metabolismo , Lipase/metabolismo , Biocatálise , Burkholderia cepacia/enzimologia , Óleo de Coco/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Ésteres/química , Lipase/química
13.
Environ Technol ; 41(14): 1837-1847, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30457937

RESUMO

Pulp wash was used as substrate for the activity of ligninolytic enzymes of the fungus Pleurotus sajor-caju. Activity of laccase (Lac) and manganese peroxidase (MnP) as well as fungal biomass occurred under four conditions: different pulp wash concentrations, pH variation at the optimal pulp wash concentration, different glucose concentrations, and different concentrations of ammonium nitrate. The best enzyme activity and biomass production were obtained with in natura pulp wash and pH corrected to 5.0 (4884 IU/L Lac; 82 IU/L MnP; 25 g/100 mL biomass). However, the addition of glucose and ammonium nitrate to the pulp wash was not necessary for increasing the enzyme activity and biomass production. Efficient removal of pulp wash chemical oxygen demand (99.66%) and biochemical oxygen demand (83.27%) occurred after the mycoremediation with P. sajor-caju in the optimized conditions. Lactuca sativa L. seeds germination bioassay showed a four-fold reduction in the residue toxicity (EC50 28.72%) after the treatment with the fungus. Our findings are consistent with the notion that pulp wash is an excellent substrate for inducing the activity of ligninolytic enzymes and producing fungal biomass, and that the biological treatment is efficient to reduce effluent toxicity.


Assuntos
Pleurotus , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Biomassa , Lacase , Lignina , Peroxidases
14.
Biotechnol Appl Biochem ; 66(5): 823-832, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31206795

RESUMO

Alternative strategies are required to develop the optimized production of fatty acids using biocatalysis; molecular docking and response surface methodology are efficient tools to achieve this goal. In the present study, we demonstrate a novel and robust methodology for the sustainable production of fatty acids from Moringa oleifera Lam oil using lipase-catalyzed hydrolysis (without the presence of emulsifiers or buffer solutions). Seven commercial lipases from Candida rugosa (CRL), Burkholderia cepacia (BCL), Thermomyces lanuginosus (TLL), Rhizopus niveus (RNL), Pseudomonas fluorescens (PFL), Mucor javanicus (MJL), and porcine pancreas (PPL) were used as biocatalysts. Initial screening showed that CRL had the highest hydrolytic activity (hydrolysis degree of 81%). Molecular docking analysis contributed to the experimental results, showing that CRL displays more stable binding free energy with oleic acid (C18:1), which is the fatty acid of highest concentration in Moringa oleifera Lam oil. To evaluate and optimize the hydrolysis process, response surface methodology (RSM) was used. The effect of temperature, mass ratio oil:water, and hydrolytic activity on enzymatic hydrolysis was evaluated by central composite design using RSM. Under the optimized conditions (temperature of 37 °C, mass ratio oil:water of 25%, and hydrolytic activity of 550 U goil -1 ), the maximum hydrolysis degree (100%) was achieved. The present study provides a robust method for the enzymatic hydrolysis of different oils for efficient and sustainable fatty acid production.


Assuntos
Ácidos Graxos/análise , Lipase/metabolismo , Simulação de Acoplamento Molecular , Moringa oleifera/metabolismo , Óleos de Plantas/metabolismo , Biocatálise , Hidrólise , Moringa oleifera/química , Óleos de Plantas/química
15.
Biotechnol Prog ; 35(4): e2816, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30969468

RESUMO

In this work, the effect of several phosphonium-based ionic liquids (ILs) on the activity of lipase from Burkholderia cepacia (BCL) was evaluated by experimental assays and molecular docking. ILs comprising different cations ([P4444 ]+ , [P444(14) ]+ , [P666(14) ]+ ) and anions (Cl- , Br- , [Deca]- , [Phosp]- , [NTf2 ]- ) were investigated to appraise the individual roles of IL ions on the BCL activity. From the activity assays, it was found that an increase in the cation alkyl chain length leads to a decrease on the BCL enzymatic activity. ILs with the anions [Phosp]- and [NTf2 ]- increase the BCL activity, while the remaining [P666(14) ]-based ILs with the Cl- , Br- , and [Deca]- anions display a negative effect on the BCL activity. The highest activity of BCL was identified with the IL [P666(14) ][NTf2 ] (increase in the enzymatic activity of BCL by 61% at 0.055 mol·L-1 ). According to the interactions determined by molecular docking, IL cations preferentially interact with the Leu17 residue (amino acid present in the BCL oxyanion hole). The anion [Deca]- has a higher binding affinity compared to Cl- and Br- , and mainly interacts by hydrogen-bonding with Ser87, an amino acid residue which constitutes the catalytic triad of BCL. The anions [Phosp]- and [NTf2 ]- have high binding energies (-6.2 and -5.6 kcal·mol-1 , respectively) with BCL, and preferentially interact with the side chain amino acids of the enzyme and not with residues of the active site. Furthermore, FTIR analysis of the protein secondary structure show that ILs that lead to a decrease on the α-helix content result in a higher BCL activity, which may be derived from an easier access of the substrate to the BCL active site.


Assuntos
Líquidos Iônicos/química , Lipase/química , Lipase/metabolismo , Ânions/química , Cátions/química , Ativação Enzimática , Estabilidade Enzimática , Hidrólise , Simulação de Acoplamento Molecular , Azeite de Oliva/química , Conformação Proteica , Espectroscopia de Infravermelho com Transformada de Fourier
16.
Carbohydr Polym ; 206: 302-308, 2019 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-30553326

RESUMO

Pineapple fibre was treated with protic ionic liquids (PILs) and the effects on the structure, composition, and properties of the fibres were evaluated. Treatment with PILs efficiently exposed the fibre surface, as confirmed by scanning electron microscopy. The chemical composition analysis revealed reductions in the lignin and hemicellulose contents in the treated fibres, promoting exposure of cellulose. The results correlated with the crystallinity index, which was greater in the treated fibres compared with that in the untreated fibres. The generated residue from the treatment of fibres with PIL (1%, v/v) showed lower levels of toxic compounds, demonstrating the advantages of this treatment over conventional biomass treatments.

17.
Int J Mol Sci ; 19(7)2018 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-29933608

RESUMO

Treated silica xerogel with protic ionic liquid (PIL) and bifunctional agents (glutaraldehyde and epichlorohydrin) is a novel support strategy used in the effective immobilization of lipase from Burkholderia cepacia (LBC) by covalent binding. As biocatalysts with the highest activity recovery yields, LBC immobilized by covalent binding with epichlorohydrin without (203%) and with PIL (250%), was assessed by the following the hydrolysis reaction of olive oil and characterized biochemically (Michaelis⁻Menten constant, optimum pH and temperature, and operational stability). Further, the potential transesterification activity for three substrates: sunflower, soybean, and colza oils, was also determined, achieving a conversion of ethyl esters between 70 and 98%. The supports and the immobilized lipase systems were characterized using Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), elemental analysis, and thermogravimetric (TG) analysis.


Assuntos
Proteínas de Bactérias/química , Enzimas Imobilizadas/química , Líquidos Iônicos/química , Lipase/química , Azeite de Oliva/química , Óleo de Soja/química , Óleo de Girassol/química , Proteínas de Bactérias/isolamento & purificação , Biocombustíveis/provisão & distribuição , Burkholderia cepacia/química , Burkholderia cepacia/enzimologia , Reagentes de Ligações Cruzadas/química , Enzimas Imobilizadas/isolamento & purificação , Epicloroidrina/química , Esterificação , Géis , Glutaral/química , Humanos , Concentração de Íons de Hidrogênio , Lipase/isolamento & purificação , Dióxido de Silício/química , Temperatura
18.
Process Biochem ; 51(6): 781-791, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27642253

RESUMO

The ability of aqueous biphasic systems (ABS) composed of polyethylene glycols of different molecular weights (PEG 400, 600 and 1000) and buffered aqueous solutions of potassium citrate/citric acid (pH = 5.0 - 8.0) to selectively extract ovalbumin from egg white was here investigated. Phase diagrams, tie-lines and tie-line lengths were determined at 25ºC and the partitioning of ovalbumin in these systems was then evaluated. Aiming at optimizing the selective extraction of ovalbumin in the studied ABS, factors such as pH, PEG molecular weight and amount of the phase-forming components were initially investigated with pure commercial ovalbumin. In almost all ABS, it was observed a preferential partitioning of ovalbumin to the polymer-rich phase, with extraction efficiencies higher than 90%. The best ABS were then applied in the purification of ovalbumin from the real egg white matrix. In order to ascertain on the ovalbumin purity and yield, sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and size exclusion high performance liquid chromatography (SE-HPLC) analyses were conducted, confirming that the isolation/purification of ovalbumin from egg white was completely achieved in a single-step with a recovery yield of 65%. The results obtained show that polymer-salt-based ABS allow the selective extraction of ovalbumin from egg white with a simpler approach and better performance than previously reported. Finally, it is shown that ovalbumin can be completely recovered from the PEG-rich phase by an induced precipitation using an inexpensive and sustainable separation platform which can be easily applied on an industrial scale.

19.
Chemosphere ; 147: 460-6, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26796340

RESUMO

Ionic liquids (ILs) are often claimed to be "environmentally friendly" compounds however, the knowledge of their potential toxicity towards different organisms and trophic levels is still limited, in particular when protic ionic liquids (PILs) are addressed. This study aims to evaluate the toxicity against various microorganisms and the biodegradability of four PILs namely, N-methyl-2-hydroxyethylammonium acetate, m-2-HEAA; N-methyl-2-hydroxyethylammonium propionate, m-2-HEAPr; N-methyl-2-hydroxyethylammonium butyrate, m-2-HEAB; and N-methyl-2-hydroxyethylammonium pentanoate, m-2-HEAP. The antimicrobial activity was determined against the two bacteria, Sthaplylococcus aureus ATCC-6533 and Escherichia coli CCT-0355; the yeast Candida albicans ATCC-76645; and the fungi Fusarium sp. LM03. The toxicity of all PILs was tested against the aquatic luminescent marine bacterium Vibrio fischeri using the Microtox(®) test. The impact of the PILs was also studied regarding their effect on lettuce seeds (Lactuta sativa). The biodegradability of these PILs was evaluated using the ratio between the biochemical oxygen demand (BOD) and the chemical oxygen demand (COD). The results show that, in general, the elongation of the alkyl chain tends to increase the negative impact of the PILs towards the organisms and biological systems under study. According to these results, m-2-HEAA and m-2-HEAP are the less and most toxic PILs studied in this work, respectively. Additionally, all the PILs have demonstrated low biodegradability.


Assuntos
Líquidos Iônicos/toxicidade , Compostos de Amônio Quaternário/toxicidade , Aliivibrio fischeri/efeitos dos fármacos , Aliivibrio fischeri/metabolismo , Antibacterianos/química , Antibacterianos/metabolismo , Antibacterianos/toxicidade , Antifúngicos/química , Antifúngicos/metabolismo , Antifúngicos/toxicidade , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Candida albicans/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Fusarium/efeitos dos fármacos , Líquidos Iônicos/química , Líquidos Iônicos/metabolismo , /crescimento & desenvolvimento , Luminescência , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/metabolismo , Staphylococcus aureus/efeitos dos fármacos
20.
Bioresour Technol ; 196: 43-8, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26226580

RESUMO

The aim of this study was to evaluate the potential of Hancornia speciosa GOMES (mangaba) seeds as a novel matrix for the production of bio-oil. The study was divided into three steps: (i) characterization of the biomass (through elemental analysis (CHN), infrared spectroscopy (FTIR-ATR), thermogravimetry (TG), and determination of biomass composition; (ii) pyrolysis of mangaba seed to obtain the bio-oil; and (iii) characterization of the bio-oil (thermogravimetry and gas chromatography/mass spectrometry-GC/qMS). The TG of the sample showed a mass loss of around 90% in 450°C. In the pyrolysis experiments the variables included temperature (450 and 600°C), sample mass (5 and 11g) and prior heating (with or without), with the best conditions of 600°C, 11g of seeds and prior heating of the furnace. The GC/qMS analysis identified carboxylic acids and hydrocarbons as the major components, besides the presence of other compounds such as furanes, phenols, nitriles, aldehydes, ketones, and amides.


Assuntos
Biocombustíveis/análise , Temperatura Alta , Sementes/química , Biomassa , Cromatografia Gasosa-Espectrometria de Massas , Lamiaceae/química , Fenóis/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Termogravimetria
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