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1.
Molecules ; 29(9)2024 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-38731512

RESUMO

Bioremediation uses the degradation abilities of microorganisms and other organisms to remove harmful pollutants that pollute the natural environment, helping return it to a natural state that is free of harmful substances. Organism-derived enzymes can degrade and eliminate a variety of pollutants and transform them into non-toxic forms; as such, they are expected to be used in bioremediation. However, since enzymes are proteins, the low operational stability and catalytic efficiency of free enzyme-based degradation systems need improvement. Enzyme immobilization methods are often used to overcome these challenges. Several enzyme immobilization methods have been applied to improve operational stability and reduce remediation costs. Herein, we review recent advancements in immobilized enzymes for bioremediation and summarize the methods for preparing immobilized enzymes for use as catalysts and in pollutant degradation systems. Additionally, the advantages, limitations, and future perspectives of immobilized enzymes in bioremediation are discussed.


Assuntos
Biodegradação Ambiental , Poluentes Ambientais , Enzimas Imobilizadas , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Poluentes Ambientais/metabolismo , Poluentes Ambientais/química , Reatores Biológicos , Substâncias Perigosas/metabolismo
2.
Food Res Int ; 186: 114161, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38729685

RESUMO

In this article, the synthesis of antioxidant peptides in the enzymatic hydrolysis of caprine casein was analyzed at three different time points (60 min, 90 min, and 120 min) using immobilized pepsin on activated and modified carbon (AC, ACF, ACG 50, ACG 100). The immobilization assays revealed a reduction in the biocatalysts' activity compared to the free enzyme. Among the modified ones, ACG 50 exhibited greater activity and better efficiency for reuse cycles, with superior values after 60 min and 90 min. Peptide synthesis was observed under all studied conditions. Analyses (DPPH, ß-carotene/linoleic acid, FRAP) confirmed the antioxidant potential of the peptides generated by the immobilized enzyme. However, the immobilized enzyme in ACG 50 and ACG 100, combined with longer hydrolysis times, allowed the formation of peptides with an antioxidant capacity greater than or equivalent to those generated by the free enzyme, despite reduced enzymatic activity.


Assuntos
Antioxidantes , Caseínas , Enzimas Imobilizadas , Glutaral , Cabras , Iridoides , Pepsina A , Peptídeos , Antioxidantes/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Caseínas/química , Animais , Pepsina A/metabolismo , Pepsina A/química , Glutaral/química , Peptídeos/química , Iridoides/química , Hidrólise , Carvão Vegetal/química
3.
Langmuir ; 40(19): 10261-10269, 2024 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-38693862

RESUMO

Carnosine is a natural bioactive dipeptide with important physiological functions widely used in food and medicine. Dipeptidase (PepD) from Serratia marcescens can catalyze the reverse hydrolytic reaction of ß-alanine with l-histidine to synthesize carnosine in the presence of Mn2+. However, it remains challenging to practice carnosine biosynthesis due to the low activity and high cost of the enzyme. Therefore, the development of biocatalysts with high activity and stability is of significance for carnosine synthesis. Here, we proposed to chelate Mn2+ to polyethylenimine (PEI) that induced rapid formation of calcium phosphate nanocrystals (CaP), and Mn-PEI@CaP was used for PepD immobilization via electrostatic interaction. Mn-PEI@CaP as the carrier enhanced the stability of the immobilized enzyme. Moreover, Mn2+ loaded in the carrier acted as an in situ activator of the immobilized PepD for facilitating the biocatalytic process of carnosine synthesis. The as-prepared immobilized enzyme (PepD-Mn-PEI@CaP) kept similar activity with free PepD plus Mn2+ (activity recovery, 102.5%), while exhibiting elevated thermal stability and pH tolerance. Moreover, it exhibited about two times faster carnosine synthesis than the free PepD system. PepD-Mn-PEI@CaP retained 86.8% of the original activity after eight cycles of batch catalysis without the addition of free Mn2+ ions during multiple cycles. This work provides a new strategy for the co-immobilization of PepD and Mn2+, which greatly improves the operability of the biocatalysis and demonstrates the potential of the immobilized PepD system for efficient carnosine synthesis.


Assuntos
Fosfatos de Cálcio , Carnosina , Dipeptidases , Enzimas Imobilizadas , Manganês , Nanopartículas , Polietilenoimina , Carnosina/química , Carnosina/metabolismo , Polietilenoimina/química , Manganês/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Fosfatos de Cálcio/química , Nanopartículas/química , Dipeptidases/metabolismo , Dipeptidases/química , Serratia marcescens/enzimologia , Biocatálise
4.
Nano Lett ; 24(15): 4682-4690, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38563501

RESUMO

Multienzyme assemblies mediated by multivalent interaction play a crucial role in cellular processes. However, the three-dimensional (3D) programming of an enzyme complex with defined enzyme activity in vitro remains unexplored, primarily owing to limitations in precisely controlling the spatial topological configuration. Herein, we introduce a nanoscale 3D enzyme assembly using a tetrahedral DNA framework (TDF), enabling the replication of spatial topological configuration and maintenance of an identical edge-to-edge distance akin to natural enzymes. Our results demonstrate that 3D nanoscale enzyme assemblies in both two-enzyme systems (glucose oxidase (GOx)/horseradish peroxidase (HRP)) and three-enzyme systems (amylglucosidase (AGO)/GOx/HRP) lead to enhanced cascade catalytic activity compared to the low-dimensional structure, resulting in ∼5.9- and ∼7.7-fold enhancements over homogeneous diffusional mixtures of free enzymes, respectively. Furthermore, we demonstrate the enzyme assemblies for the detection of the metabolism biomarkers creatinine and creatine, achieving a low limit of detection, high sensitivity, and broad detection range.


Assuntos
Enzimas Imobilizadas , Glucose Oxidase , Enzimas Imobilizadas/química , Peroxidase do Rábano Silvestre/química , Glucose Oxidase/química , DNA/química
5.
Nat Commun ; 15(1): 3308, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38632275

RESUMO

Continuous-flow biocatalysis utilizing immobilized enzymes emerged as a sustainable route for chemical synthesis. However, inadequate biocatalytic efficiency from current flow reactors, caused by non-productive enzyme immobilization or enzyme-carrier mismatches in size, hampers its widespread application. Here, we demonstrate a general-applicable and robust approach for the fabrication of a high-performance enzymatic continuous-flow reactor via integrating well-designed scalable isoporous block copolymer (BCP) membranes as carriers with an oriented and productive immobilization employing material binding peptides (MBP). Densely packed uniform enzyme-matched nanochannels of well-designed BCP membranes endow the desired nanoconfined environments towards a productive immobilized phytase. Tuning nanochannel properties can further regulate the complex reaction process and fortify the catalytic performance. The synergistic design of enzyme-matched carriers and efficient enzyme immobilization empowers an excellent catalytic performance with >1 month operational stability, superior productivity, and a high space-time yield (1.05 × 105 g L-1 d-1) via a single-pass continuous-flow process. The obtained performance makes the designed nano- and isoporous block copolymer membrane reactor highly attractive for industrial applications.


Assuntos
Reatores Biológicos , Enzimas Imobilizadas , Enzimas Imobilizadas/química , Biocatálise , Catálise , Polímeros/química
6.
Anal Sci ; 40(5): 951-958, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38598048

RESUMO

Daily monitoring of serum uric acid levels is very important to provide appropriate treatment according to the constitution and lifestyle of individual hyperuricemic patients. We have developed a suspension-based assay to measure uric acid by adding a sample solution to the suspension containing micro-sized particles immobilized on uricase and horseradish peroxidase (HRP). In the proposed method, the mediator reaction of uricase, HRP, and uric acid produces resorufin from Amplex red. This resorufin is adsorbed onto enzyme-immobilized micro-sized particles simultaneously with its production, resulting in the red color of the micro-sized particles. The concentration of resorufin on the small surface area of the microscopic particles achieves a colorimetric analysis of uric acid with superior visibility. In addition, ethanol-induced desorption of resorufin allowed quantitative measurement of uric acid using a 96-well fluorescent microplate reader. The limit of detection (3σ) and RSD (n = 3) were estimated to be 2.2 × 10-2 µg/mL and ≤ 12.1%, respectively. This approach could also be applied to a portable fluorometer.


Assuntos
Colorimetria , Enzimas Imobilizadas , Fluorometria , Peroxidase do Rábano Silvestre , Urato Oxidase , Ácido Úrico , Ácido Úrico/sangue , Ácido Úrico/química , Ácido Úrico/análise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Urato Oxidase/química , Urato Oxidase/metabolismo , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Tamanho da Partícula , Humanos , Suspensões , Oxazinas/química
7.
J Mater Chem B ; 12(16): 3996-4003, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38563677

RESUMO

Encapsulation of enzymes within porous materials has shown great promise for protecting enzymes from denaturation, increasing their tolerance to harsh environments and promoting their industrialization. However, controlling the conformational freedom of the encapsulated enzymes to enhance their catalytic performance remains a great challenge. To address this issue, herein, following immobilization of GOx and HRP on a thermo-responsive porous poly(styrene-maleic-anhydride-N-isopropylacrylamide) (PSMN) membrane, a GOx-HRP@PSMN@HZIF-8 composite was fabricated by encapsulating GOx-HRP@PSMN in hollow ZIF-8 (HZIF-8) with liposome (L) as the sacrificial template. The improved conformational freedom for enzymes arising from the hollow cavity formed in ZIF-8 through the removal of L enhanced the mass transfer and dramatically promoted the catalytic activity of the composite. Interestingly, at high temperature, the coiled PN moiety in PSMN provided the confinement effect for GOx-HRP, which also significantly boosted the catalytic performance of the composites. Compared to the maximum catalytic reaction rates (Vmax) of GOx-HRP@PSMN@LZIF-8, the free enzyme and GOx-HRP@ZIF-8, the Vmax of the GOx-HRP@PSMN@HZIF-8 composite exhibited an impressive 17.8-fold, 10.8-fold and 6.0-fold enhancement at 37 °C, respectively. The proposed composites successfully demonstrated their potential as catalytic platforms for the colorimetric detection of glucose in a cascade reaction. This study paves a new way for overcoming the current limitations of immobilizing enzymes in porous materials and the use of smart polymers for the potential fabrication of enzyme@polymer@MOF composites with tunable conformational freedom and confinement effect.


Assuntos
Enzimas Imobilizadas , Glucose Oxidase , Estruturas Metalorgânicas , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Estruturas Metalorgânicas/química , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Peroxidase do Rábano Silvestre/química , Peroxidase do Rábano Silvestre/metabolismo , Polímeros/química , Propriedades de Superfície , Porosidade , Tamanho da Partícula , Catálise , Biocatálise , Poliestirenos/química
8.
J Chromatogr A ; 1722: 464896, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38631224

RESUMO

In this study, a novel magnetic bead-based ligand fishing method was developed for rapid discovery of monoterpene indoles as monoamine oxidase A inhibitors from natural products. In order to improve the screening efficiency, two different magnetic beads, i.e. amine and carboxyl terminated magnetic beads, were comprehensively compared in terms of their ability to immobilize monoamine oxidase A (MAOA), biocatalytic activity and specific adsorption rates for affinity ligands. Carboxyl terminated magnetic beads performed better for MAOA immobilization and demonstrated superior performance in ligand fishing. The MAOA immobilized magnetic beads were applied to screen novel monoamine oxidase inhibitors in an alkaloid-rich plant, Hunteria zeylanica. Twelve MAOA affinity ligands were screened out, and ten of them were identified as monoterpene indole alkaloids by HPLC-Obitrap-MS/MS. Among them, six ligands, namely geissoschizol, vobasinol, yohimbol, dihydrocorynanthenol, eburnamine and (+)-isoeburnamine which exhibited inhibitory activity against MAOA with low IC50 values. To further explore their inhibitory mechanism, enzyme kinetic analysis and molecular docking studies were conducted.


Assuntos
Simulação de Acoplamento Molecular , Inibidores da Monoaminoxidase , Monoaminoxidase , Inibidores da Monoaminoxidase/química , Inibidores da Monoaminoxidase/farmacologia , Inibidores da Monoaminoxidase/isolamento & purificação , Monoaminoxidase/metabolismo , Monoaminoxidase/química , Ligantes , Indóis/química , Monoterpenos/química , Monoterpenos/isolamento & purificação , Cinética , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida de Alta Pressão/métodos , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Enzimas Imobilizadas/antagonistas & inibidores , Humanos , Extratos Vegetais/química
9.
Biomolecules ; 14(4)2024 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-38672520

RESUMO

Ethyl (S)-4-chloro-3-hydroxybutyrate ((S)-CHBE) is an important chiral intermediate in the synthesis of the cholesterol-lowering drug atorvastatin. Studying the use of SpyTag/SpyCatcher and SnoopTag/SnoopCatcher systems for the asymmetric reduction reaction and directed coupling coenzyme regeneration is practical for efficiently synthesizing (S)-CHBE. In this study, Spy and Snoop systems were used to construct a double-enzyme directed fixation system of carbonyl reductase (BsCR) and glucose dehydrogenase (BsGDH) for converting 4-chloroacetoacetate (COBE) to (S)-CHBE and achieving coenzyme regeneration. We discussed the enzymatic properties of the immobilized enzyme and the optimal catalytic conditions and reusability of the double-enzyme immobilization system. Compared to the free enzyme, the immobilized enzyme showed an improved optimal pH and temperature, maintaining higher relative activity across a wider range. The double-enzyme immobilization system was applied to catalyze the asymmetric reduction reaction of COBE, and the yield of (S)-CHBE reached 60.1% at 30 °C and pH 8.0. In addition, the double-enzyme immobilization system possessed better operational stability than the free enzyme, and maintained about 50% of the initial yield after six cycles. In summary, we show a simple and effective strategy for self-assembling SpyCatcher/SnoopCatcher and SpyTag/SnoopTag fusion proteins, which inspires building more cascade systems at the interface. It provides a new method for facilitating the rapid construction of in vitro immobilized multi-enzyme complexes from crude cell lysate.


Assuntos
Enzimas Imobilizadas , Glucose 1-Desidrogenase , Glucose 1-Desidrogenase/metabolismo , Glucose 1-Desidrogenase/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Biocatálise , Concentração de Íons de Hidrogênio , Hidroxibutiratos/química , Temperatura , Catálise , Oxirredutases do Álcool/química , Oxirredutases do Álcool/metabolismo , Carbonil Redutase (NADPH)/metabolismo , Carbonil Redutase (NADPH)/química
10.
Biosensors (Basel) ; 14(4)2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38667161

RESUMO

Enzyme-based biosensors commonly utilize the drop-casting method for their surface modification. However, the drawbacks of this technique, such as low reproducibility, coffee ring effects, and challenges in mass production, hinder its application. To overcome these limitations, we propose a novel surface functionalization strategy of enzyme crosslinking via inkjet printing for reagentless enzyme-based biosensors. This method includes printing three functional layers onto a screen-printed electrode: the enzyme layer, crosslinking layer, and protective layer. Nanomaterials and substrates are preloaded together during our inkjet printing. Inkjet-printed electrodes feature a uniform enzyme deposition, ensuring high reproducibility and superior electrochemical performance compared to traditional drop-casted ones. The resultant biosensors display high sensitivity, as well as a broad linear response in the physiological range of the serum phosphate. This enzyme crosslinking method has the potential to extend into various enzyme-based biosensors through altering functional layer components.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Enzimas Imobilizadas , Fosfatos , Enzimas Imobilizadas/química , Eletrodos , Impressão , Reprodutibilidade dos Testes
11.
Biosensors (Basel) ; 14(4)2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38667189

RESUMO

L-Lactate is an important bioanalyte in the food industry, biotechnology, and human healthcare. In this work, we report the development of a new L-lactate electrochemical biosensor based on the use of multiwalled carbon nanotubes non-covalently functionalized with avidin (MWCNT-Av) deposited at glassy carbon electrodes (GCEs) as anchoring sites for the bioaffinity-based immobilization of a new recombinant biotinylated lactate oxidase (bLOx) produced in Escherichia coli through in vivo biotinylation. The specific binding of MWCNT-Av to bLOx was characterized by amperometry, surface plasmon resonance (SPR), and electrochemical impedance spectroscopy (EIS). The amperometric detection of L-lactate was performed at -0.100 V, with a linear range between 100 and 700 µM, a detection limit of 33 µM, and a quantification limit of 100 µM. The proposed biosensor (GCE/MWCNT-Av/bLOx) showed a reproducibility of 6.0% and it was successfully used for determining L-lactate in food and enriched serum samples.


Assuntos
Avidina , Técnicas Biossensoriais , Ácido Láctico , Oxigenases de Função Mista , Nanotubos de Carbono , Nanotubos de Carbono/química , Oxigenases de Função Mista/química , Avidina/química , Técnicas Eletroquímicas , Ressonância de Plasmônio de Superfície , Enzimas Imobilizadas/química , Escherichia coli , Biotinilação , Eletrodos , Espectroscopia Dielétrica , Limite de Detecção
12.
Mar Drugs ; 22(4)2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38667763

RESUMO

Marine microalgae Schizochytrium sp. have a high content of docosahexaenoic acid (DHA), an omega-3 fatty acid that is attracting interest since it prevents certain neurodegenerative diseases. The obtention of a bioactive and purified DHA fatty acid ester using a whole-integrated process in which renewable sources and alternative methodologies are employed is the aim of this study. For this reason, lyophilized Schizochytrium biomass was used as an alternative to fish oil, and advanced extraction techniques as well as enzymatic modification were studied. Microalgal oil extraction was optimized via a surface-response method using pressurized liquid extraction (PLE) obtaining high oil yields (29.06 ± 0.12%) with a high concentration of DHA (51.15 ± 0.72%). Then, the enzymatic modification of Schizochytrium oil was developed by ethanolysis using immobilized Candida antarctica B lipase (Novozym® 435) at two reaction temperatures and different enzymatic loads. The best condition (40 °C and 200 mg of lipase) produced the highest yield of fatty acid ethyl ester (FAEE) (100%) after 8 h of a reaction attaining a cost-effective and alternative process. Finally, an enriched and purified fraction containing DHA-FAEE was obtained using open-column chromatography with a remarkably high concentration of 93.2 ± 1.3% DHA. The purified and bioactive molecules obtained in this study can be used as nutraceutical and active pharmaceutical intermediates of marine origin.


Assuntos
Ácidos Docosa-Hexaenoicos , Ésteres , Lipase , Microalgas , Estramenópilas , Ácidos Docosa-Hexaenoicos/química , Lipase/metabolismo , Lipase/química , Estramenópilas/química , Microalgas/química , Ésteres/química , Enzimas Imobilizadas/química , Proteínas Fúngicas , Biomassa , Óleos de Peixe/química , Lipídeos/química , Óleos/química , Organismos Aquáticos , Ácidos Graxos/química , Ácidos Graxos/análise
13.
Int J Mol Sci ; 25(8)2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38674004

RESUMO

Phenolic compounds, originating from industrial, agricultural, and urban sources, can leach into flowing waters, adversely affecting aquatic life, biodiversity, and compromising the quality of drinking water, posing potential health hazards to humans. Thus, monitoring and mitigating the presence of phenolic compounds in flowing waters are essential for preserving ecosystem integrity and safeguarding public health. This study explores the development and performance of an innovative sensor based on screen-printed electrode (SPE) modified with graphene (GPH), poly(3,4-ethylenedioxythiophene) (PEDOT), and tyrosinase (Ty), designed for water analysis, focusing on the manufacturing process and the obtained electroanalytical results. The proposed biosensor (SPE/GPH/PEDOT/Ty) was designed to achieve a high level of precision and sensitivity, as well as to allow efficient analytical recoveries. Special attention was given to the manufacturing process and optimization of the modifying elements' composition. This study highlights the potential of the biosensor as an efficient and reliable solution for water analysis. Modification with graphene, the synthesis and electropolymerization deposition of the PEDOT polymer, and tyrosinase immobilization contributed to obtaining a high-performance and robust biosensor, presenting promising perspectives in monitoring the quality of the aquatic environment. Regarding the electroanalytical experimental results, the detection limits (LODs) obtained with this biosensor are extremely low for all phenolic compounds (8.63 × 10-10 M for catechol, 7.72 × 10-10 M for 3-methoxycatechol, and 9.56 × 10-10 M for 4-methylcatechol), emphasizing its ability to accurately measure even subtle variations in the trace compound parameters. The enhanced sensitivity of the biosensor facilitates detection and quantification in river water samples. Analytical recovery is also an essential aspect, and the biosensor presents consistent and reproducible results. This feature significantly improves the reliability and usefulness of the biosensor in practical applications, making it suitable for monitoring industrial or river water.


Assuntos
Técnicas Biossensoriais , Compostos Bicíclicos Heterocíclicos com Pontes , Grafite , Monofenol Mono-Oxigenase , Fenóis , Polímeros , Rios , Poluentes Químicos da Água , Técnicas Biossensoriais/métodos , Grafite/química , Rios/química , Polímeros/química , Fenóis/análise , Poluentes Químicos da Água/análise , Compostos Bicíclicos Heterocíclicos com Pontes/química , Enzimas Imobilizadas/química , Técnicas Eletroquímicas/métodos , Eletrodos , Limite de Detecção
14.
Int J Biol Macromol ; 266(Pt 2): 131329, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38574906

RESUMO

The bacterial nanocellulose (BnC) membranes were produced extracellularly by a novel aerobic acetic acid bacterium Komagataeibacter melomenusus. The BnC was modified in situ by adding carboxymethyl cellulose (CMC) into the culture media, obtaining a BnC-CMC product with denser fibril arrangement, improved rehydration ratio and elasticity in comparison to BnC. The proteolytic enzyme bromelain (Br) and antimicrobial peptide nisin (N) were immobilized to BnC matrix by ex situ covalent binding and/or adsorption. The optimal Br immobilization conditions towards the maximized specific proteolytic activity were investigated by response surface methodology as factor variables. At optimal conditions, i.e., 8.8 mg/mL CMC and 10 mg/mL Br, hyperactivation of the enzyme was achieved, leading to the specific proteolytic activity of 2.3 U/mg and immobilization efficiency of 39.1 %. The antimicrobial activity was observed against Gram-positive bacteria (S. epidermidis, S. aureus and E. faecalis) for membranes with immobilized N and was superior when in situ modified BnC membranes were used. N immobilized on the BnC or BnC-CMC membranes was cytocompatible and did not cause changes in normal human dermal fibroblast cell morphology. BnC membranes perform as an efficient carrier for Br or N immobilization, holding promise in wound debridement and providing antimicrobial action against Gram-positive bacteria, respectively.


Assuntos
Acetobacteraceae , Bromelaínas , Celulose , Nisina , Nisina/farmacologia , Nisina/química , Bromelaínas/química , Bromelaínas/farmacologia , Celulose/química , Celulose/farmacologia , Acetobacteraceae/química , Humanos , Antibacterianos/farmacologia , Antibacterianos/química , Cicatrização/efeitos dos fármacos , Enzimas Imobilizadas/química , Enzimas Imobilizadas/farmacologia , Nanoestruturas/química , Testes de Sensibilidade Microbiana
15.
Food Chem ; 449: 139180, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38579650

RESUMO

Maple syrup, a popular natural sweetener has a high content of sucrose, whose consumption is linked to different health issues such as obesity and diabetes. Hence, within this paper, the conversion of sucrose to prebiotics (fructo-oligosaccharides, FOS) was proposed as a promising approach to obtaining a healthier, value-added product. Enzymatic conversion was optimized with respect to key experimental factors, and thereafter derived immobilized preparation of fructosyltransferase (FTase) from Pectinex® Ultra SP-L (FTase-epoxy Purolite, 255 IU/g support) was successfully utilized to produce novel functional product in ten consecutive reaction cycles. The product, obtained under optimal conditions (60 °C, 7.65 IU/mL, 12 h), resulted in 56.0% FOS, 16.7% sucrose, and 27.3% monosaccharides of total carbohydrates, leading to a 1.6-fold reduction in caloric content. The obtained products` prebiotic potential toward the probiotic strain Lactobacillus plantarum 299v was demonstrated. The changes in physico-chemical and sensorial characteristics were esteemed as negligible.


Assuntos
Acer , Proteínas de Bactérias , Hexosiltransferases , Oligossacarídeos , Prebióticos , Sacarose , Prebióticos/análise , Oligossacarídeos/química , Oligossacarídeos/metabolismo , Hexosiltransferases/metabolismo , Hexosiltransferases/química , Sacarose/metabolismo , Sacarose/química , Acer/química , Acer/metabolismo , Lactobacillus plantarum/metabolismo , Lactobacillus plantarum/enzimologia , Lactobacillus plantarum/química , Biocatálise , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo
16.
Talanta ; 274: 126042, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38583326

RESUMO

This work emphasizes the utilization of biochar, a renewable material, as an interesting platform for anchoring redox mediators and bioreceptors in the development of economic, environmentally friendly biosensors. In this context, Fe(III) ions were preconcentrated on highly functionalized activated biochar, allowing the stable synthesis of Prussian blue nanostructures with an average size of 58.3 nm. The determination of glucose was carried out by indirectly monitoring the hydrogen peroxide generated through the enzymatic reaction, followed by its subsequent redox reaction with reduced Prussian blue (also known as Prussian white) in a typical electrochemical-chemical mechanism. The EDC/NHS (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-Hydroxysuccinimide) pair was employed for the stable covalent immobilization of the enzyme on biochar. The biosensor demonstrated good enzyme-substrate affinity, as evidenced by the Michaelis-Menten apparent kinetic constant (4.16 mmol L-1), and analytical performance with a wide linear dynamic response range (0.05-5.0 mmol L-1), low limits of detection (0.94 µmol L-1) and quantification (3.13 µmol L-1). Additionally, reliable repeatability, reproducibility, stability, and selectivity were obtained for the detection of glucose in both real and spiked human saliva and blood serum samples.


Assuntos
Técnicas Biossensoriais , Carvão Vegetal , Ferrocianetos , Glucose , Nanoestruturas , Ferrocianetos/química , Técnicas Biossensoriais/métodos , Nanoestruturas/química , Carvão Vegetal/química , Glucose/análise , Glucose/química , Humanos , Enzimas Imobilizadas/química , Glucose Oxidase/química , Glucose Oxidase/metabolismo , Glicemia/análise , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/análise , Limite de Detecção
17.
Talanta ; 274: 126007, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38583331

RESUMO

Hypoxanthine (Hx), produced by adenosine triphosphate (ATP) metabolism, is a valuable indicator that determines the quality and degradation status of meat products and is also an important biochemical marker to certain diseases such as gout. The rapid emergence of paper-based enzyme biosensors has already revolutionized its on-site determination. But it is still limited by the complex patterning and fabrication, unstable enzyme and uneven coloration. This work aims to develop an eco-friendly method to construct engineered paper microfluidic, which seeks to produce reaction and non-reaction zones without any patterning procedure. Chito-oligosaccharide (COS), derived from shrimp shells, was used to modify nitrocellulose membranes and immobilize xanthine oxidase (XOD) and chromogenic agent of nitro blue tetrazolium chloride (NBT). After modification, micro fluids could converge into the modification area and Hx could be detected by XOD-catalyzed conversion. Due to the positively charged cationic basic properties of COS, the enzyme storage stability and the color homogeneity could be greatly strengthened through the electrostatic attraction between COS and XOD and formazan product. The detection limit (LOD) is 2.30 µM; the linear range is 0.05-0.35 mM; the complete test time can be as short as 5 min. The COS-based biosensor shows high specificity and can be used directly for Hx in complex samples such as fish and shrimp samples, and different broths. This biosensor is eco-friendly, nontechnical, economical and therefore a compelling platform for on-site or home-based detection of food freshness.


Assuntos
Técnicas Biossensoriais , Colódio , Hipoxantina , Oligossacarídeos , Xantina Oxidase , Animais , Oligossacarídeos/química , Oligossacarídeos/análise , Técnicas Biossensoriais/métodos , Hipoxantina/análise , Hipoxantina/química , Colódio/química , Xantina Oxidase/química , Xantina Oxidase/metabolismo , Peixes , Quitina/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Química Verde/métodos , Propriedades de Superfície , Limite de Detecção
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 315: 124271, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38613899

RESUMO

As an important biomarker for renal related diseases, detection of urea is playing a vital role in human biofluids on clinical diagnosis concern. In this work, a synthetic salicyaldehyde based imine fluorophore was synthesized using sonication method and conjugated with urease which was used as fluorescent biosensor for the detection of urea in serum samples. This enzyme based biosensor has shown a good selectivity and sensitivity towards urea with the linear range from 2 to 80 mM and the detection limit of 73 µM. The sensing response obtain is highly agreeing with existing analytical technique for urea detection which strongly recommends this biosensor for clinical application.


Assuntos
Técnicas Biossensoriais , Ureia , Urease , Humanos , Ureia/análise , Ureia/sangue , Técnicas Biossensoriais/métodos , Urease/química , Urease/metabolismo , Limite de Detecção , Fluorometria/métodos , Espectrometria de Fluorescência/métodos , Corantes Fluorescentes/química , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo
19.
J Agric Food Chem ; 72(17): 9967-9973, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38639643

RESUMO

The use of convertible immobilized enzyme carriers is crucial for biphasic catalytic reactions conducted in Pickering emulsions. However, the intense mechanical forces during the conversion process lead to enzyme leakage, affecting the stability of the immobilized enzymes. In this study, a CO2-responsive switchable Janus (CrSJ) nanoparticle (NP) was developed using silica NP, with one side featuring aldehyde groups and the other side adsorbing N,N-dimethyldodecylamine. A switchable Pickering emulsion catalytic system for biphasic interface reactions was prepared by covalently immobilizing lipase onto the CrSJ NPs. The CO2-responsive nature of the CrSJ NPs allowed for rapid conversion of the Pickering emulsion, and covalent immobilization substantially reduced lipase leakage while enhancing the stability of the immobilization during the conversion process. Impressively, after repeated transformations, the Pickering emulsion still maintains its original structure. Following 10 consecutive cycles of esterification and hydrolysis reactions, the immobilized enzyme's activity remains at 77.7 and 79.5% of its initial activity, respectively. The Km of the CrSJ catalytic system showed no significant change compared to the free enzyme, while its Vmax values were 1.2 and 1.6 times that of the free enzyme in esterification and hydrolysis reactions, respectively.


Assuntos
Biocatálise , Dióxido de Carbono , Emulsões , Enzimas Imobilizadas , Lipase , Nanopartículas , Lipase/química , Lipase/metabolismo , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Emulsões/química , Nanopartículas/química , Dióxido de Carbono/química , Dióxido de Carbono/metabolismo , Esterificação , Estabilidade Enzimática , Cinética , Dióxido de Silício/química , Catálise , Hidrólise
20.
Bioprocess Biosyst Eng ; 47(5): 737-751, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38607415

RESUMO

Enzymatic hydrolysis plays a pivotal role in transforming lignocellulosic biomass. Addressing alternate techniques to optimize the utilization of cellulolytic enzymes is one strategy to improve its efficiency and lower process costs. Cellulases are highly specific and environmentally benign biocatalysts that break down intricate polysaccharides into simple forms of sugars. In contrast to the most difficult and time-consuming enzyme immobilization processes, in this research, we studied simple, mild, and successful techniques for immobilization of pure cellulase on magnetic nanocomposites using glutaraldehyde as a linker and used in the application of sorghum residue biomass. Fe3O4 nanoparticles were coated with chitosan from the co-precipitation method, which served as an enzyme carrier. The nanoparticles were observed under XRD, Zeta Potential, FESEM, VSM, and FTIR. The size morphology results presented that the Cs@Fe3O4 have 42.2 nm, while bare nanoparticles (Fe3O4) have 31.2 nm in size. The pure cellulase reaches to 98.07% of loading efficiency and 71.67% of recovery activity at optimal conditions. Moreover, immobilized enzyme's pH stability, thermostability, and temperature tolerance were investigated at suitable conditions. The kinetic parameters of free and immobilized enzyme were estimated as Vmax; 29 ± 1.51 and 27.03 ± 2.02 µmol min-1 mg-1, Km; 4.7 ± 0.49 mM and 2.569 ± 0.522 mM and Kcat; 0.13 s-1, and 0.89 s-1. Sorghum residue was subjected to 2% NaOH pre-treatment at 50 â„ƒ. Pre-treated biomass contains cellulose of 64.8%, used as a raw material to evaluate the efficiency of reducing sugar during hydrolysis and saccharification of free and immobilized cellulase, which found maximum concentration of glucose 5.42 g/L and 5.12 g/L on 72 h. Thus, our study verifies the use of immobilized pure cellulase to successfully hydrolyze raw material, which is a significant advancement in lignocellulosic biorefineries and the reusability of enzymes.


Assuntos
Celulase , Quitosana , Enzimas Imobilizadas , Nanopartículas de Magnetita , Sorghum , Quitosana/química , Enzimas Imobilizadas/química , Celulase/química , Sorghum/química , Nanopartículas de Magnetita/química , Estabilidade Enzimática , Cinética , Biomassa , Hidrólise
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