Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 12.328
Filtrar
1.
Water Sci Technol ; 81(1): 29-39, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32293586

RESUMO

Magnetic laccase nanoflowers (MNFs-Lac) were successfully prepared through encapsulating Fe3O4 magnetic nanoparticles into the interior of laccase nanoflowers by grafting N-(phosphonomethyl)iminodiacetic acid (PMIDA) as an interconnecting bridge between the magnetic nanoparticles and copper ions. The characterizations by scanning electron microscopy and transmission electron microscopy showed that MNFs-Lac were spherical, porous and flower-like crystals with diameters of ∼10 µm, and Fe3O4 nanoparticles were encapsulated in the interior of MNFs-Lac evenly. The enzymatic activity and reusability of MNFs-Lac were evaluated based on the degradation efficiency for malachite green (MG). The degradation parameters, concerning initial MG concentration, dosage of MNFs-Lac, reaction temperature, pH value and reaction time, were optimized through single-factor experiments. Under the optimal conditions, 25 mg·L-1 MG can be degraded almost completely by 1.5 g·L-1 MNFs-Lac within 15 min. When the MNFs-Lac were reused for 18 times, the degradation efficiency of MG was still as high as 90%. These results suggested that the modified preparation method improved greatly the reusability of MNFs-Lac, which made them more suitable to degrade MG in a water environment.


Assuntos
Lacase , Nanopartículas de Magnetita , Enzimas Imobilizadas , Corantes de Rosanilina
2.
Bioresour Technol ; 307: 123258, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32247276

RESUMO

In this work, a mono- and a bi-enzymatic analytical immobilized enzyme reactors (IMERs) were developed as prototypes for biosynthetic purposes and their performances in the in-flow synthesis of nucleoside analogues of pharmaceutical interest were evaluated. Two biocatalytic routes based on nucleoside 2'-deoxyribosyltransferase from Lactobacillus reuteri (LrNDT) and uridine phosphorylase from Clostridium perfrigens (CpUP)/purine nucleoside phosphorylase from Aeromonas hydrophila (AhPNP) were investigated in the synthesis of 2'-deoxy, 2',3'-dideoxy and arabinonucleoside derivatives. LrNDT-IMER catalyzed the synthesis of 5-fluoro-2'-deoxyuridine and 5-iodo-2'-deoxyuridine in 65-59% conversion yield, while CpUP/AhPNP-IMER provided the best results for the preparation of arabinosyladenine (60% conversion yield). Both IMERs proved to be promising alternatives to chemical routes for the synthesis of nucleoside analogues. The developed in-flow system represents a powerful tool for the fast production on analytical scale of nucleosides for preliminary biological tests.


Assuntos
Enzimas Imobilizadas , Nucleosídeos , Biocatálise , Pentosiltransferases , Purina-Núcleosídeo Fosforilase
3.
Bioresour Technol ; 307: 123193, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32203868

RESUMO

Production of biodiesel from lipids of Serratia sp. ISTD04 by lipase of Pseudomonas sp. ISTPL3 immobilised on biocomposite materials to increase the enzyme stability and reusability was studied. Lipase extracted, partially purifiedand immobilized onto activated biochar, impregnated with calcite obtained from biomineralization-based conversion of CO2 from ISTD04, and bioactive ceramics materials, Na2Ca2Si3O9 prepared by chemical process. The composition, structure and texture of biocomposite materials determined by SEM and EDS methods. The composition of synthesized biodiesel was determined by GC-MS. The results imply that the immobilized lipase on activated biochar impregnated with calcite gave the maximum yield of fatty acid methyl esters (FAME:97.41%) followed by immobilized lipase on biochar (FAME:94.91), immobilized lipase on glass-ceramic (FAME:91.50%) and NaOH (FAME:85.63%). The reusability of lipase immobilized on activated biochar impregnated with calcite retained 75.11%and 50% catalytic activity after 5 and 10 cycles of transesterification reaction, respectively.


Assuntos
Biocombustíveis , Lipase , Dióxido de Carbono , Enzimas Imobilizadas , Esterificação , Lipídeos , Serratia
4.
Bioresour Technol ; 307: 123223, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32220818

RESUMO

In this study, crude oils extracted from spent coffee grounds (SCG) and olive pomace (OP) were used as raw-material to synthesize low-calorie triacylglycerols, either by acidolysis with capric acid, or by interesterification with ethyl caprate, in solvent-free media, catalyzed by sn-1,3 regioselective lipases. The Rhizopus oryzae lipase (ROL) was immobilized in magnetite nanoparticles (MNP-ROL) and tested as novel biocatalyst. MNP-ROL performance was compared with that of the commercial immobilized Thermomyces lanuginosus lipase (Lipozyme TL IM). For both oils, Lipozyme TL IM preferred interesterification over acidolysis. MNP-ROL catalyzed reactions were faster and acidolysis was preferred with yields of c.a. 50% new triacylglycerols after 3 h acidolysis of OP or SCG oils. MNP-ROL was very stable following the Sadana deactivation model with half-lives of 163 h and 220 h when reused in batch acidolysis and interesterification of OP oil, respectively.


Assuntos
Nanopartículas de Magnetita , Petróleo , Catálise , Café , Enzimas Imobilizadas , Esterificação , Lipase , Lipídeos , Azeite de Oliva
5.
Nat Commun ; 11(1): 1049, 2020 02 26.
Artigo em Inglês | MEDLINE | ID: mdl-32103000

RESUMO

Enzymatic digestion for protein sequencing usually requires much time, and does not always result in high sequence coverage. Here we report the use of aqueous microdroplets to accelerate enzymatic reactions and, in particular, to improve protein sequencing. When a room temperature aqueous solution containing 10 µM myoglobin and 5 µg mL-1 trypsin is electrosonically sprayed (-3 kV) from a homemade setup to produce tiny (∼9 µm) microdroplets, we obtain 100% sequence coverage in less than 1 ms of digestion time, in sharp contrast to 60% coverage achieved by incubating the same solution at 37 °C for 14 h followed by analysis with a commercial electrospray ionization source that produces larger (∼60 µm) droplets. We also confirm the sequence of the therapeutic antibody trastuzumab (∼148 kDa), with a sequence coverage of 100% for light chains and 85% for heavy chains, demonstrating the practical utility of microdroplets in drug development.


Assuntos
Hormônio Adrenocorticotrópico/análise , Mioglobina/análise , Análise de Sequência de Proteína/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Trastuzumab/análise , Hormônio Adrenocorticotrópico/metabolismo , Enzimas Imobilizadas/química , Humanos , Mioglobina/metabolismo , Trastuzumab/metabolismo , Tripsina/metabolismo
6.
Nat Commun ; 11(1): 838, 2020 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-32047166

RESUMO

Protein-protein interactions are spatially regulated in living cells to realize high reaction efficiency, as seen in naturally existing electron-transfer chains. Nevertheless, arrangement of chemical/biochemical components at the artificial device interfaces does not possess the same level of control. Here we report a tetrahedral DNA framework-enabled bulk enzyme heterojunction (BEH) strategy to program the multi-enzyme catalytic cascade at the interface of electrochemical biosensors. The construction of interpenetrating network of BEH at the millimeter-scale electrode interface brings enzyme pairs within the critical coupling length (CCL) of ~10 nm, which in turn greatly improve the overall catalytic cascade efficiency by ~10-fold. We demonstrate the BEH generality with a range of enzyme pairs for electrochemically detecting clinically relevant molecular targets. As a proof of concept, a BEH-based sarcosine sensor enables single-step detection of the metabolic biomarker of sarcosine with ultrasensitivity, which hold the potential for precision diagnosis of early-stage prostate cancer.


Assuntos
Técnicas Biossensoriais/métodos , DNA/química , Técnicas Eletroquímicas/métodos , Eletrodos , Enzimas Imobilizadas , Técnicas Biossensoriais/instrumentação , Catálise , Técnicas de Química Analítica/métodos , Técnicas Eletroquímicas/instrumentação , Enzimas/química , Desenho de Equipamento , Humanos , Limite de Detecção , Nanopartículas Metálicas , Modelos Teóricos , Nanotecnologia/métodos , Sarcosina
7.
Chemosphere ; 248: 125917, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32004892

RESUMO

Quorum sensing signals regulate various functions within activated sludge processes such as formation of microbial aggregates. Disturbance of this signaling system, known as quorum quenching (QQ), provides opportunities for eliminating some problems related to biological wastewater treatment (e.g., biofouling and excess sludge production). However, it is poorly understood how and to what extent QQ systems can affect the microbial aggregation processes and the following floc formation. In particular, an in-depth structural characterization at the scale of microbial aggregate while considering nutrient conditions in the reactor is still largely disregarded. Here, we evaluated the QQ effects at the short-term time scale (i.e., after 4 h for the exogenous period and 19 h for exogenous/endogenous period), by combining advanced techniques for microbial characterization (flow cytometry, CARD-FISH, and confocal laser scanning microscopy) and conventional physical-chemical assessments. The results indicated that by implementing QQ agents (immobilized Acylase I enzyme in porous alginate beads) the abundance of single cells and suspended microbial aggregates in the supernatant did not show significant changes during the exogenous period. Conversely, at the end of the exogenous/endogenous period a significant increase of single prokaryotic cells, small and large microbial aggregates favored the growth of grazers, including free-living nanoflagellates and ciliates. Flocs became looser and thinner than those in the control reactor, thus affecting the sludge settling behavior. Inability of microbial community in degradation of soluble protein during the endogenous period confirmed that the QQ agents are likely to inhibit the secretion of protease enzyme within microbial communities of activated sludge.


Assuntos
Percepção de Quorum/fisiologia , Eliminação de Resíduos Líquidos/métodos , Incrustação Biológica , Reatores Biológicos , Enzimas Imobilizadas , Nutrientes , Esgotos , Águas Residuárias
8.
Bioresour Technol ; 302: 122887, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32018086

RESUMO

Immobilization of industrially important enzymes on supports is important to decrease the cost of the overall enzymatic production procedure. Herein, a novel method for synthesizing a new support, magnetic rice straw (MRS) in one step is reported: rice straw (RS) was soaked with Fe2+ ions and these were further reduced to form embedded Fe2O3 nanoparticles on the RS surface, forming MRS. This material presented a magnetic saturation value of 27.32 emu g-1. Lipase immobilization on MRS resulted in 94.3% immobilization efficiency and 91.3 mg g-1 of enzyme loading, which are higher than immobilization on native RS. The lipase stability was increased approximately 8-fold at 70 °C. The lipase-MRS composite was tested in the esterification reaction of biodiesel production, where it showed prominent reusability. Therefore, this novel and rapid synthesis method can provide ecological and economic support for enzyme immobilization and industrially important product formation.


Assuntos
Lipase , Oryza , Estabilidade Enzimática , Enzimas Imobilizadas , Esterificação , Fenômenos Magnéticos
9.
Biochim Biophys Acta Proteins Proteom ; 1868(4): 140377, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31982578

RESUMO

The N-succinylamino acid racemase/o-succinylbenzoate synthase (NSAR/OSBS) subfamily from the enolase superfamily contains different enzymes showing promiscuous N-substituted-amino acid racemase (NxAR) activity. These enzymes were originally named as N-acylamino acid racemases because of their industrial application. Nonetheless, they are pivotal in several enzymatic cascades due to their versatility to catalyze a wide substrate spectrum, allowing the production of optically pure d- or l-amino acids from cheap precursors. These compounds are of paramount economic interest, since they are used as food additives, in the pharmaceutical and cosmetics industries and/or as chiral synthons in organic synthesis. Despite its economic importance, the discovery of new N-succinylamino acid racemases has become elusive, since classical sequence-based annotation methods proved ineffective in their identification, due to a high sequence similarity among the members of the enolase superfamily. During the last decade, deeper investigations into different members of the NSAR/OSBS subfamily have shed light on the classification and identification of NSAR enzymes with NxAR activity of biotechnological potential. This review aims to gather the dispersed information on NSAR/OSBS members showing NxAR activity over recent decades, focusing on their biotechnological applications and providing practical advice to identify new enzymes.


Assuntos
Isomerases de Aminoácido/química , Isomerases de Aminoácido/metabolismo , Biotecnologia , Isomerases de Aminoácido/classificação , Isomerases de Aminoácido/genética , Evolução Biológica , Enzimas Imobilizadas , Modelos Moleculares , Filogenia , Engenharia de Proteínas , Alinhamento de Sequência
10.
Environ Sci Technol ; 54(2): 1223-1231, 2020 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-31899628

RESUMO

Carbonic anhydrases convert CO2 to bicarbonate at a high turnover rate up to 106 s-1, but their actual applications in CO2 conversion processes are hampered by their poor stability. This study reports highly loaded and stabilized bovine carbonic anhydrase (bCA) upon being immobilized onto electrospun polymer nanofibers in the form of enzyme precipitate coating (EPC). The EPC protocol, consisting of enzyme covalent attachment, precipitation, and cross-linking, maintained 65.3% of initial activity even after being incubated in aqueous solution at room temperature under shaking at 200 rpm for 868 days. EPC also showed strong resistance to the treatment of the metal chelation agent, ethylenediaminetetraacetic acid, and molecular dynamic simulation was carried out to elucidate the prevention of metal leaching from the active site of bCA upon being cross-linked in the form of EPC. Highly stable EPC with high bCA loading was employed for the conversion of bubbling CO2 to bicarbonate, and the bicarbonate solution was utilized as a carbon source for expedited microalgae growth in a separate bioreactor. The addition of EPC in the bubbling CO2 reactor resulted in 134 and 231% accelerated microalgae growths compared to the controls with and without 25 mM sodium bicarbonate, respectively. EPC with high enzyme loading and unprecedentedly successful stabilization of enzyme stability has a great potential to be used for the development of various enzyme-mediated CO2 conversion and utilization technologies.


Assuntos
Anidrases Carbônicas , Microalgas , Nanofibras , Animais , Bicarbonatos , Dióxido de Carbono , Bovinos , Enzimas Imobilizadas
11.
Chem Commun (Camb) ; 56(13): 2004-2007, 2020 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-31960849

RESUMO

The operation of wearable epidermal biofuel cells is prone to rapid irreversible deactivation effects under dynamic sweat pH changes from neutral to acidic. We demonstrate that the encapsulation of lactate-oxidase (LOx) within a hydrophobic protective carbon-paste anode imparts unusually high stability during dynamically changing pH fluctuations and allows the BFC to continue harvesting the lactate bioenergy even after long exposures to acidic conditions. The unique power-recovery ability of the carbon-paste BFC after its failure in harsh pH is attributed to the protective action of the non-polar paste environment.


Assuntos
Fontes de Energia Bioelétrica , Técnicas Biossensoriais/métodos , Glucose Oxidase/metabolismo , Carbono/química , Eletrodos , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Glucose Oxidase/química , Concentração de Íons de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Ácido Láctico/química , Suor/química , Dispositivos Eletrônicos Vestíveis
12.
Chemosphere ; 246: 125676, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31918078

RESUMO

Covalent-immobilization of the laccase enzyme onto the iron oxide nanoparticles was achieved using N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDAC) as cross-linkers. The presence of sulphur moeity in the laccase immobilized nanoparticles (LNPs) observed through Scanning Electron Microscopy- Energy dispersive X-ray spectroscopy (SEM-EDS) spectra confirmed the immobilization of laccase enzyme. The TEM analysis of iron oxide nanoparticles (FNPs), chitosan coated iron nanoparticles (CNPs) and laccase immobilized nanoparticles (LNPs) confirmed their sizes around 12, 15 and 20 nm, respectively. The effect of LNPs in degrading chlorpyrifos under field conditions was studied by simulating the conditions in a column. Column A, which was used as control showed more leaching of chlorpyrifos as compared to column B containing LNPs. The sorption coefficient (Kd) value obtained for control (column A) and LNPs containing column B were 21.6 and 112.3 L/kg, respectively. LNPs altered the Kd values of soil thereby showing lesser leaching potential. Higher the Kd value, lesser will be the leaching potential in the ground water. Copper in laccase enzyme resulted in hydrolysis of chlorpyrifos. Chitosan used for coating on FNPs and soil organic matter resulted in the adsoption of chlorpyrifos. Current results will allow a better assessment of the role of LNPs as a competent deterrent in chlorpyrifos mobility and degradation.


Assuntos
Clorpirifos/análise , Lacase/química , Nanopartículas/química , Poluentes do Solo/química , Quitosana/química , Clorpirifos/metabolismo , Cobre , Enzimas Imobilizadas/química , Compostos Férricos , Lacase/metabolismo , Solo
13.
J Environ Manage ; 256: 109740, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31989972

RESUMO

Among hazardous pollutants, 2,4-Dinitrophenol (2,4-DNP) is considered highly toxic and possesses a remarkable resistance to degradation. Therefore, investigation of the possible mechanisms for removal of such pollutants is important. Laccase enzyme can decompose phenolics despite the fact that its application has been limited due to lack of possibility to reuse it. Immobilization can overcome this problem. In this paper, laccase complexes with montmorillonite K10 and zeolite were used to decompose 2,4-DNP with concentrations of 1.5 mg l-1 and 50 mg kg-1 in synthetic wastewater and soil, respectively. The maximum removal of pollutant from wastewater in samples containing laccase-zeolite and laccase-montmorillonite complexes were 99 and 93.3%, respectively, which occurred at 4 h incubation compared with 6 h for free laccase. The maximum removal of pollutant from soil was observed for all treatments after 16 h of incubation. The maximum removal for samples containing free laccase, laccase-zeolite, and laccase-montmorillonite complexes were 98.5%, 98.6%, and 90.4%, respectively. Control sample also showed maximum removal of 35.8%. In general, application of laccase-zeolite complexes in aqueous environment, and these complexes and free laccases in soil was found very effective in degradation of 2,4-DNP. Hence, the use of laccase, especially immobilized laccases, for removal of 2,4-DNP from environment is promising.


Assuntos
Lacase , Purificação da Água , 2,4-Dinitrofenol , Enzimas Imobilizadas , Solo , Águas Residuárias
14.
J Agric Food Chem ; 68(5): 1373-1381, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31927950

RESUMO

Most of the microorganisms can form biofilms, which makes biofilms an abundant bioresource to be exploited. Due to the limitations of the application of current immobilization methods for biofilms, we developed an immobilization method called the biofilm polysaccharide display (BPD) strategy while maintaining the native biofilm structure and catalytic microenvironment of Clostridium acetobutylicum B3. Lipase Lip181 showed significant improvements in stability after chemical immobilization. For example, immobilized Lip181 retained 74.23% of its original activity after incubation for 14 days, while free Lip181 was totally deactivated. In addition, immobilized Lip181 maintained high residual activity (pH 5.0-11.0), which showed improved resistance to pH changes. Notably, this method did not decrease but slightly increased the relative activity of Lip181 from 6.39 to 6.78 U/mg. Immobilized Lip181 was used to prepare cinnamyl acetate, and it showed a maximum yield of 85.09%. Overall, this biofilm immobilization method may promote the development of biocatalytic and biofilm materials.


Assuntos
Materiais Biocompatíveis/química , Biofilmes , Clostridium acetobutylicum/química , Lipase/metabolismo , Polissacarídeos/química , Biocatálise , Clostridium acetobutylicum/fisiologia , Estabilidade Enzimática , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Concentração de Íons de Hidrogênio , Cinética , Lipase/química , Polissacarídeos/metabolismo
15.
Appl Biochem Biotechnol ; 190(1): 218-231, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31332676

RESUMO

Yeast surface display has emerged as a viable approach for self-immobilization enzyme as whole-cell catalysts. Herein, we displayed Candida rugosa lipase 1 (CRL LIP1) on the cell wall of Pichia pastoris for docosahexaenoic acid (DHA) enrichment in algae oil. After a 96-h culture, the displayed CRL LIP1 achieved the highest activity (380 ± 2.8 U/g) for hydrolyzing olive oil under optimal pH (7.5) and temperature (45 °C) conditions. Additionally, we improved the thermal stability of displayed LIP1, enabling retention of 50% of its initial bioactivity following 6 h of incubation at 45 °C. Furthermore, the content of DHA enhanced from 40.61% in original algae oil to 50.44% in glyceride, resulting in a 1.24-fold increase in yield. The displayed CRL LIP1 exhibited an improved thermal stability and a high degree of bioactivity toward its native macromolecule substrates algae oil and olive oil, thereby expanding its potential for industrial applications in fields of food and pharmaceutical. These results suggested that surface display provides an effective strategy for simultaneous convenient expression and target protein immobilization.


Assuntos
Proteínas de Bactérias/metabolismo , Candida/enzimologia , Ácidos Docosa-Hexaenoicos/metabolismo , Temperatura Alta , Lipase/metabolismo , Estabilidade Enzimática , Enzimas Imobilizadas/metabolismo
16.
Appl Biochem Biotechnol ; 190(1): 1-17, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31297755

RESUMO

A novel concept of membrane bioreactor based on polymeric ionic liquids laccase membrane has been implemented in batch process for decolorization of the anthraquinonic dye Remazol Brillant Blue R (RBBR). New laccase immobilization strategy has been optimized by casting the enzyme into a polymeric inclusion membrane (PIM) using ionic liquids (ILs) and polyvinyl chloride (PVC) leading to laccase polymeric IL membrane (PILM). Four different ILs (1-octyl-3-metylimidazolium bis(trifluoromethylsulfonyl)imide, [OMIM][NTF2]; cholinium bis(trifluoromethylsulfonyl)imide, [Ch ol][NTF2]; cholinium dihydrogenphosphate, [Chol][H2PO4] and hydroxyethylammonium formate, [HEA][Fo]) have been screened and mixed to constitute the active phase of the support of PIM. This strategy has been fully succeeded since high laccase immobilization rates were recorded (about 98%) when using the optimal mixture containing three ILs (45% [OMIM][NTf2]/5% [Chol][NTf2]/2.5% [HEA][Fo]) and supplemented by 0.5% glutaraldehyde. It was found that such mixture contributes to increase the stability and reusability of laccase-PILM during eight successive assays in a batch discontinued stirred reactor. Decolorization rate of 75% has been reached in the batch decolorization process of RBBR with high reusability yield. Graphical Abstract Decolorization of RBBR by PILM_laccase.


Assuntos
Reatores Biológicos , Reagentes para Ligações Cruzadas/química , Enzimas Imobilizadas/metabolismo , Líquidos Iônicos/química , Lacase/metabolismo , Membranas Artificiais , Cor
17.
Appl Biochem Biotechnol ; 190(1): 138-147, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31309412

RESUMO

In this presented work, preparation of poly(AAm) cryogel, peroxidase immobilization onto the poly(AAm) cryogel, and usability of these enzyme modified cryogels for phenolic compounds removal were described. For this purpose, poly(AAm) cryogels were synthesized by using cryocopolymerization technique at sub-zero temperatures, and covalently functionalized with peroxidase enzyme by EDC/NHS chemistry. Characterization of the cryogels was carried out by FTIR, SEM, and EDX analysis. Maximum peroxidase loading onto poly(AAm) cryogel was found to be as 127.30 mg/g cryogel. Kinetic parameters of free and immobilized peroxidases were also investigated along with the stability tests. Finally, phenolic compounds removal efficiency of the peroxidase immobilized poly(AAm) cryogel was studied towards model phenolics such as phenol, bisphenol A, guaiacol, pyrogallol, and catechol; and very high phenolic removal efficiency was recorded.


Assuntos
Criogéis , Enzimas Imobilizadas/metabolismo , Peroxidase/metabolismo , Fenóis/isolamento & purificação , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Cinética , Temperatura
18.
Appl Biochem Biotechnol ; 190(1): 148-165, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31313241

RESUMO

Feasibility and stability were evaluated of a continuous multi-batch process for converting oleuropein (OLE) from olive leaf extract to the bioactive product hydroxytyrosol (HT). Carrier beads made of three different materials (calcium alginate, chitosan with deacetylated α-chitin nanofibers (DEChN), or porous ceramic) were investigated for morphology, thermogravimetric, sorption, and viscoelastic properties. Enzymatic hydrolysis of OLE conducted in a packed bed bioreactor containing cellulase immobilized to carrier beads yielded OLE degradation rates of ~ 90% and an average HT yield of ~ 70% over 20 batches. Ultimately, inorganic porous ceramic beads were less costly and exhibited superior performance relative to organic carriers and thus were deemed most suitable for industrial-scale HT production. Systems utilizing enzyme immobilization within packed bed reactors hold promise for achieving efficient production of valuable bioproducts from discarded biomass materials.


Assuntos
Celulase/metabolismo , Enzimas Imobilizadas/metabolismo , Iridoides/metabolismo , Olea/metabolismo , Álcool Feniletílico/análogos & derivados , Folhas de Planta/metabolismo , Alginatos/química , Biomassa , Reatores Biológicos , Cerâmica , Quitosana/química , Hidrólise , Microscopia Eletrônica de Varredura , Álcool Feniletílico/metabolismo , Especificidade por Substrato , Termogravimetria
19.
Appl Biochem Biotechnol ; 190(1): 270-292, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31342308

RESUMO

The enzyme phytase has important applications in animal feed, because it favors the bioavailability of phosphorus present in phytate, an antinutritional compound widely found associated with plant proteins. However, for feed applications, the phytase must withstand high temperatures during the feed pelleting process, as well as the gastrointestinal conditions of the animal. This work evaluates the feasibility of immobilizing phytase on hydroxyapatite (HA) nanoparticles, in order to improve its properties. HA is a material with excellent physicochemical characteristics for enzyme immobilization, and it can also act as an inorganic source of phosphorus and calcium in animal feed. The strong affinity of the phytase for the support resulted in rapid adsorption, with total immobilization yield and recovered activity greater than 100%. After immobilization, the phytase showed a broader activity profile in terms of pH and temperature, together with considerably higher thermoresistance at 80 and 90 °C. As a proof of concept, it was shown that the phytase immobilized on HA presented good resistance to acidic conditions and resistance to proteolysis when passing through simulated gastrointestinal conditions of fish. The findings showed that phytase immobilized onto HA presents suitable properties and has great potential for use in animal feed.


Assuntos
6-Fitase/metabolismo , Ração Animal , Durapatita/química , Enzimas Imobilizadas/metabolismo , Nanopartículas/química , Animais , Peixes , Temperatura Alta , Concentração de Íons de Hidrogênio , Concentração Osmolar , Proteólise
20.
J Chromatogr A ; 1609: 460454, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31443966

RESUMO

We propose a new capillary electrophoresis (CE)-based open-tubular immobilized enzyme microreactor (OT-IMER) and its application in acetylcholinesterase (AChE) assays. The IMER is fabricated at the capillary inlet (reactor length of ∼1 cm) with the inner surface modified by a micropore-structured layer (thickness of ∼220 nm, pore size of ∼15-20 nm). The use of IMER accomplishes the enzymatic reaction and separation/detection of the products in the same capillary within 3 min. The feasibility of the proposed method is evaluated via online analysis of the activity and inhibition of AChE enzymes. Such method exhibits good reproducibility with relative standard deviation (RSD) of less than 4% for 20 runs, and the enzyme remains over 82% of the initial activity after usage of 7 days. The IMERs are successfully applied to detect the organophosphorus pesticide, paraoxon, in three types of vegetable juice samples with a limit of detection of as low as 61 ng mL-1. Results show that the spiked samples are in the range of 89.6-105.9% with RSD less than 2.7%, thereby indicating its satisfactory level of accurate and reliable analysis of real samples by using the proposed method. Our study indicates that, with combination of advantages of both porous-layer capillary and CE OT-IMER, the proposed method is capable to enhance enzymatic reactions and to achieve rapid analysis with simple instrumentation and operation, thus would pave the way for extensive application of CE-based IMERs in a variety of bioanalysis.


Assuntos
Acetilcolinesterase/análise , Reatores Biológicos , Eletroforese Capilar/métodos , Ensaios Enzimáticos/métodos , Enzimas Imobilizadas/metabolismo , Inibidores da Colinesterase/análise , Sucos de Frutas e Vegetais , Cinética , Paraoxon/análise , Porosidade , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA