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1.
Artículo en Inglés | MEDLINE | ID: mdl-38811468

RESUMEN

In this research, we examined the production of hyaluronic acid (HA) by Streptococcus zooepidemicus strain MW26985 using different substrates and potato peel waste (PPW) as an affordable substrate. First, culture medium components, including carbon and nitrogen sources, were optimized for bacterial HA production. Five different carbon sources (glucose, sucrose, lactose, sago starch, and potato starch, at a concentration of 30 g/L) and three distinct nitrogen sources (peptone, yeast extract, and ammonium sulfate, at a concentration of 10 g/L) were investigated. Glucose, among the carbon sources, and yeast extract, among nitrogen sources, produced the most HA which was determined as 1.41 g/L. Afterward, potato peel sugars were extracted by dilute acid and enzymatic hydrolysis and then employed as a cost-effective carbon source for the growth of S. zooepidemicus. Based on the results, the fermentation process yielded 0.59 g/L HA from potato peel sugars through acid hydrolysis and 0.92 g/L HA from those released by enzymatic hydrolysis. The supplementation of both hydrolyzates with glucose as an additional carbon source enhanced HA production to 0.95 g/L and 1.18 g/L using acidic and enzymatic hydrolyzates, respectively. The cetyltrimethylammonium bromide (CTAB) turbidimetric method was used to evaluate the concentration of HA in the fermentation broth using the colorimetric method. Also, the peaks observed by Fourier transform infrared (FTIR) spectroscopy confirmed that the exopolysaccharide (EPS) was composed of HA. These observations demonstrate that potato peel residues can be a novel alternative as a carbon source for the economical production of HA by S. zooepidemicus.

2.
Talanta ; 273: 125854, 2024 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-38447342

RESUMEN

MicroRNAs (miRNAs) play several crucial roles in the physiological and pathological processes of the human body. They are considered as important biomarkers for the diagnosis of various disorders. Thus, rapid, sensitive, selective, and affordable detection of miRNAs is of great importance. However, the small size, low abundance, and highly similar sequences of miRNAs impose major challenges to their accurate detection in biological samples. In recent years, metal-organic frameworks (MOFs) have been applied as promising sensing materials for the fabrication of different biosensors due to their distinctive characteristics, such as high porosity and surface area, tunable pores, outstanding adsorption affinities, and ease of functionalization. In this review, the applications of MOFs and MOF-derived materials in the fabrication of fluorescence, electrochemical, chemiluminescence, electrochemiluminescent, and photoelectrochemical biosensors for the detection of miRNAs and their detection principle and analytical performance are discussed. This paper attempts to provide readers with a comprehensive knowledge of the fabrication and sensing mechanisms of miRNA detection platforms.


Asunto(s)
Técnicas Biosensibles , Estructuras Metalorgánicas , MicroARNs , Humanos , Fotometría , Porosidad
3.
Carbohydr Polym ; 320: 121138, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37659783

RESUMEN

A myriad of therapeutic agents and drug delivery systems are available to the surgeons for treating orthopedic implant-associated infections (OIAI), but only very few have demonstrated their effectiveness in preventing bacteria colonization and biofilm formation due to challenges in the local and sustainable therapeutic release. To address this issue, in this work, a thermosensitive injectable hydrogel based on chitosan (CH)-integrated hydroxyapatite nanoparticles (HAP NPs) containing vancomycin (Van) and quercetin (QC)-loaded in F127 micelles (CH-HAP-FQ-Van hydrogel) was fabricated with potential application in the treatment of OIAI. This dual drug delivery system demonstrated a pH-sensitive drug release pattern. In addition, 100 % growth inhibition of Staphylococcus aureus for a duration of 14 days was observed. Apart from the strong antioxidant activities owing to the co-administration of QC even after 432 h, this composite hydrogel revealed 95.88 ± 2.8 % S. aureus biofilm eradication. By consideration of degradation stability (53.52 ± 4.24 %) during 60 days along with smart gelation within 10 min at 37 °C and easy injectability, CH-HAP-FQ-Van hydrogel could be used as a promising ideal local drug delivery system for implant-related infections.

4.
Int J Biol Macromol ; 248: 125938, 2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37487996

RESUMEN

This study investigates the fabrication of edible coating based on Plantago ovata seed mucilage (POSM). The films were prepared from POSM (1 %, w/v), glycerol (75 %, based on POSM mass), and xanthan gum (XG: 20, 30 and 40 %, based on POSM mass) by a casting method, and their physicochemical, mechanical, thermal, morphological, and barrier properties were determined. Results indicated the development of highly transparent (transparency values: 1.36 ± 0.05 to 2.42 ± 0.09) and hydrophobic films (contact angle: 101.57 ± 0.34 to107.08 ± 0.55o) with very low water vapor permeability (WVP: 2.77 ± 0.02 × 10-12 to 1.98 ± 0.04 × 10-12 g s-1m-1Pa-1), slight water solubility (31.14 ± 0.46 to 23.08 ± 0.82 %), and good mechanical properties (tensile strength: 30.87 ± 0.96 to 61.80 ± 0.71 MPa). Morphological studies also indicated smooth and uniform surfaces without pores and cracks. In addition, the films showed good antioxidant activity (61.46 to 68.71 %), and their antibacterial activity against E. coli, S. aureus and P. aeruginosa was also demonstrated. The applicability of the developed films to extend the shelf life of strawberries was shown by comparing the appearance of dip-coated strawberries and the control sample within 8 days at room temperature. Based on the results, the developed biofilms have great potential for edible coating and packaging applications.


Asunto(s)
Películas Comestibles , Plantago , Escherichia coli , Staphylococcus aureus , Permeabilidad , Semillas/química , Embalaje de Alimentos/métodos
5.
Anal Bioanal Chem ; 415(5): 899-911, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36544030

RESUMEN

In this work, a novel, sensitive, and rapid electrochemical biosensor was employed to detect lysozyme (Lys) using a double receptor of molecular imprinted polymer (MIP)-aptamer. First, a glassy carbon electrode (GCE) was modified with a nanocomposite consisting of multi-wall carbon nanotubes (MWCNTs), nitrogen-doped carbon quantum dots (N-CQDs), and chitosan. Subsequently, aptamer (Apt)-Lys complex was immobilized on MWCNTs-N-CQDs-chitosan/GCE via binding between carboxyl groups present in the nanocomposite and the terminal amine groups of the aptamer. Following that, methylene blue monomer was electrochemically polymerized around the Apt-Lys complex on the MWCNTs-N-CQDs-chitosan/GCE surface. Finally, after the template removal, the remaining cavities along with the aptamers created a new hybrid receptor of MIP-aptamer. The MWCNTs-N-CQDs-chitosan nanocomposite could provide large amounts of carboxyl groups for binding to amino-functionalized aptamers, considerable electrical conductivity, and a high surface-to-volume ratio. These beneficial features facilitated the Apt-Lys complex immobilization and gave improved electrochemical signal. The obtained MIP-aptamer hybrid receptor allowed lysozyme determination even at concentrations as low as 4.26 fM within the functional range of 1 fM to 100 nM.


Asunto(s)
Aptámeros de Nucleótidos , Técnicas Biosensibles , Quitosano , Nanotubos de Carbono , Quitosano/química , Aptámeros de Nucleótidos/química , Polímeros , Muramidasa/química , Nanotubos de Carbono/química , Electrodos , Nitrógeno , Técnicas Electroquímicas , Límite de Detección
6.
Environ Res ; 216(Pt 3): 114643, 2023 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-36341789

RESUMEN

The spread of antibiotic resistant genes has become a serious global concern. Thus, the development of efficient antibiotic monitoring systems to reduce their environmental risks is of great importance. Here, a potent electrochemical sensor was fabricated to detect metronidazole (MNZ) on the basis of green synthesis of Fe3O4 nanoparticles (NPs) using Sambucus ebulus L. leaves alcoholic plant extract as a safe and impressive reducing and stabilizing agent. Several analyses such as X-ray diffraction (XRD), Fourier transform infrared spectrophotometer (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscope (FESEM), energy dispersive X-ray spectroscopy (EDX), and dynamic light scattering (DLS) confirmed the production of homogeneous, monodisperse, regular, and stable magnetite NPs with a spherical morphology. The as-prepared Fe3O4NPs were afterwards applied to evaluate the electrochemical activity of MNZ by merging them with graphene nanosheets (GR NSs) on the glassy carbon electrode (GCE). The GR/Fe3O4NPs/GCE represented extraordinary catalytic activity toward MNZ with two dynamic ranges of 0.05-5 µM and 5-120 µM, limit of detection (LOD) of 0.23 nM, limit of quantification (LOQ) of 0.76 nM, and sensitivity of 7.34 µA µM-1 cm-2. The fabricated sensor was further employed as a practical tool for electrochemical detection of MNZ in real aqueous samples.


Asunto(s)
Nanopartículas de Magnetita , Metronidazol , Metronidazol/análisis , Técnicas Electroquímicas/métodos , Antibacterianos , Nanopartículas de Magnetita/química , Carbono/química , Fenómenos Magnéticos
7.
J Environ Manage ; 322: 116090, 2022 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-36049311

RESUMEN

The long process time and low product quality are major challenges in the composting process. To overcome the above challenges, the effects of produced biosurfactants on composting were investigated as a biological model. Pseudomonas aeruginosa IBRC-M 11180 inoculum and its supernatant were used as in-situ and ex-situ treatments in the composting process, respectively. The results showed that the presence of rhamnolipid biosurfactants in the composting process could improve many parameters such as maximum temperature, electrical conductivity (EC), cation exchange capacity (CEC), C/N, and germination index (GI). The GI value above 80% was observed for in-situ and ex-situ reactors on 12th day, while for the control was observed on 18th day, which indicates the significant effects of rhamnolipids on process time reduction. The C/N ratios of final compost for ex-situ, in-situ, and control reactors were 12.83, 13.27, and 17.05, respectively, which indicates the rhamnolipids also improves the quality of the final product. To better understand the performance of the rhamnolipids in the composting, wettability changes of the compost surface were evaluated. Our results show that the produced rhamnolipids altered the waste wettability from intermediate wet (θ = 85°) to water-wet (θ = 40°). It can be concluded that the presence of biosurfactants in composting leads to an increase in the contact surface area of microorganisms with nutrient sources and consequently improves the composting process. Furthermore, comparative studies showed that the in-situ treatment has better effects on composting, thus it can be an economically significant achievement because of the high cost of ex-situ treatment.


Asunto(s)
Compostaje , Eliminación de Residuos , Alimentos , Glucolípidos , Nitrógeno , Suelo , Agua
8.
Sci Rep ; 12(1): 10128, 2022 06 16.
Artículo en Inglés | MEDLINE | ID: mdl-35710936

RESUMEN

The bacterium Pantoea sp. BCCS 001 GH produces an exopolysaccharide (EPS) named Pantoan through using sugar beet molasses (SBM) as an inexpensive and widely available carbon source. This study aims to investigate the kinetics and optimization of the Pantoan biosynthesis using Pantoea sp. BCCS 001 GH in submerged culture. During kinetics studies, the logistic model and Luedeking-Piret equation are precisely fit with the obtained experimental data. The response surface methodology (RSM)-central composite design (CCD) method is applied to evaluate the effects of four factors (SBM, peptone, Na2HPO4, and Triton X-100) on the concentration of Pantoan in batch culture of Pantoea sp. BCCS 001 GH. The experimental and predicted maximum Pantoan production yields are found 9.9 ± 0.5 and 10.30 g/L, respectively, and the best prediction factor concentrations are achieved at 31.5 g/L SBM, 2.73 g/L peptone, 3 g/L Na2HPO4, and 0.32 g/L Triton X-100 after 48 h of submerged culture fermentation, at 30 °C. The functional groups and major monosaccharides (glucose and galactose) of a purified Pantoan are described and confirmed by 1HNMR and FTIR. The produced Pantoan is also characterized by thermogravimetric analysis and the rheological properties of the biopolymer are investigated. The present work guides the design and optimization of the Pantoea sp. BCCS 001 GH culture media, to be fine-tuned and applied to invaluable EPS, which can be applicable in food and biotechnology applications.


Asunto(s)
Pantoea , Medios de Cultivo/química , Fermentación , Cinética , Melaza , Octoxinol , Pantoea/metabolismo , Peptonas
9.
Heliyon ; 8(12): e12265, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36619422

RESUMEN

Present study focused on improvement of the formulation of conventional hard gelatin capsules using gastric acid-resistant polymers. We have utilized the same approach of making conventional drug capsules to develop novel capsules with delayed release properties. For this purpose, delayed-release capsules were produced by improving the formulation of hard gelatin capsules. In addition, the effect of adding intestinal polymers such as Hydroxy propyl methyl cellulose phthalate, Glucomannan, and Polyvinyl alcohol to hard gelatin capsules were investigated. The capsules' release rate was determined. The degradation tests in an acidic environment were performed and the results were recorded. In fact, the delayed-release hard gelatin capsules pass through the stomach with small amount of the drug release; but their shell remains intact and dissolves as it enters the intestine environment. This article shows that enteric polymers with out interactions, only by changing the formulations will have delayed release properties. this makes sensitive drugs pass through stomach environment and have higher absorption.

10.
Int J Biol Macromol ; 177: 306-316, 2021 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-33621567

RESUMEN

PAMAM grafted chitosan as biocompatible adsorbent was synthesized through Michael addition of methyl acrylate followed by amidation of ethylenediamine on the chitosan backbone. Then, the adsorption capacity of bioadsorbents were assessed by employing two anionic dyes. The adsorption experiments were carried out using a batch adsorption system. The influence of various operational variables such as different PAMAM generations, pH, adsorbent dosage, contact time, initial dye concentration and temperature on the maximum adsorption capacity (qm) were investigated. The adsorbent consists of second generation of PAMAM (CS-PAMAM G2) demonstrated high removal efficiency for both dyes. The maximum adsorption capacity of CS-PAMAM G2 for Congo Red at certain operational conditions was 559.3 mg/g; while the maximum adsorption capacity for Amido Black 10B at certain operational conditions was 489.8 mg/g; which revealed endothermic and exothermic nature of adsorption process for Congo Red and Amido Black 10B, respectively. These results were then well confirmed by thermodynamics studies. Also, kinetic studies showed that the dye adsorption process followed a pseudo-second-order kinetic model. Moreover, among various applied isotherms, the experimental data were well-fitted by Sips model. Consequently, CS-PAMAM G2 showed superior potential for the removal of dyes from aqueous phase.


Asunto(s)
Negro de Almidón/química , Quitosano/química , Rojo Congo/química , Dendrímeros/química , Contaminantes Químicos del Agua , Purificación del Agua
11.
J Pharm Biomed Anal ; 188: 113394, 2020 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-32504972

RESUMEN

Frequency of seizures is often managed by a wide group of antiepileptic drugs. Regarding the pharmacokinetic variability, narrow targeted range, and difficulty of detecting signs of toxicity based on laboratory responses, therapeutic monitoring of antiepileptic drugs can play a pivotal role in optimizing the drug dosage. Electrochemical sensors and biosensors can facilitate analysis of these drugs due to their unique advantages such as fast analysis, sensitivity, selectivity, and low cost. This review article, for the first time, describes the recent advances in electrochemical sensors and biosensors developed for the analysis of antiepileptic drugs. General electrochemical measuring techniques and types of applied electrode substrates were described first. To simplify the work, various chemical and biological modifiers applied to improve the sensitivity and selectivity of the sensors were classified and explained briefly. Finally, the future prospective on the development of electrochemical platforms in the quantification of antiepileptic drugs will be presented.


Asunto(s)
Anticonvulsivantes , Técnicas Biosensibles , Anticonvulsivantes/uso terapéutico , Técnicas Electroquímicas , Electrodos
12.
Ecotoxicol Environ Saf ; 190: 110088, 2020 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-31865204

RESUMEN

Environmental xenoestrogen, Bisphenol A (BPA), is a vitally important industrial raw chemical which can bring about a wide variety of adverse impacts on our health and environment. Therefore, it is imperative to develop efficacious systems to measure BPA and improve the life quality. Herein, a mixture of titanium dioxide nanoparticles (TiO2NPs) and glutaraldehyde cross-linked chitosan (GA-CS) loaded into a carbon nanotubes paste matrix to construct a novel electrochemical sensor (TiO2NPs/GA-CS/CNTPE) with a synergetic intensified current signal for the quantitative analysis of BPA. The surface morphology of the modified sensor was assessed by field emission scanning electron microscope (FESEM), X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX). The prepared TiO2NPs/GA-CS/CNTPE displayed increased electrocatalytic activity toward BPA. The calibration curve of BPA shows linear response in the BPA concentration range of 0.01-6 µM with the lowest limit of detection of 9.58 nM (S/N = 3). The sensor exhibited high sensitivity and selectivity, good reproducibility, desirable stability and excellent performance in detection of BPA in real samples, which prove that TiO2NPs/GA-CS/CNTPE is quite applicable for food, medical and environmental analyses.


Asunto(s)
Compuestos de Bencidrilo/análisis , Monitoreo del Ambiente/métodos , Sustancias Peligrosas/análisis , Fenoles/análisis , Compuestos de Bencidrilo/toxicidad , Quitosano/química , Técnicas Electroquímicas/métodos , Electrodos , Sustancias Peligrosas/toxicidad , Límite de Detección , Nanopartículas , Nanotubos de Carbono/química , Fenoles/toxicidad , Reproducibilidad de los Resultados , Titanio
13.
J Mater Chem B ; 7(34): 5211-5221, 2019 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-31364687

RESUMEN

Microbial exopolysaccharides (EPSs) have recently served as an efficient substrate for the production of biocompatible metal nanoparticles (NPs) given their favorable stabilizing and reducing properties due to the presence of polyanionic functional groups in their structure. In the present work, Pantoea sp. BCCS 001 GH was used to produce EPS-stabilized biogenic Fe NPs as a complex through a novel biosynthesis reaction. Physicochemical characterization of the EPS-Fe complex was performed, indicating high thermal stability, desirable magnetic properties due to the uniform distribution of the Fe NPs with the average size of ∼10 nm and spherical shape within the EPS matrix. In addition, the in vivo toxicity of the EPS-stabilized Fe NPs was evaluated to investigate their potential for the treatment of iron deficiency anemia. Biological blood parameters and organ histology studies confirmed very high safety of the biosynthesized composite, making EPS-Fe a suitable candidate with an economical and environment friendly synthesis method for a wide spectrum of potential fields in medicine.


Asunto(s)
Depuradores de Radicales Libres/farmacología , Compuestos de Hierro/farmacología , Nanopartículas/química , Encuestas Nutricionales , Pantoea/metabolismo , Polisacáridos/farmacología , Administración Oral , Animales , Supervivencia Celular/efectos de los fármacos , Suplementos Dietéticos , Depuradores de Radicales Libres/administración & dosificación , Depuradores de Radicales Libres/metabolismo , Humanos , Compuestos de Hierro/administración & dosificación , Compuestos de Hierro/metabolismo , Células MCF-7 , Masculino , Ratones , Ratones Endogámicos BALB C , Nanopartículas/administración & dosificación , Nanopartículas/metabolismo , Tamaño de la Partícula , Polisacáridos/administración & dosificación , Polisacáridos/biosíntesis , Propiedades de Superficie
14.
J Environ Health Sci Eng ; 17(1): 305-317, 2019 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-31321049

RESUMEN

The main objective of this study is to evaluate the treatment and simultaneous production of methane from low-strength petrochemical wastewater by single membrane-less microbial electrolysis cells. To achieve this objective, the influence of variables such as applied voltage, operation mode, and hydraulic retention time (HRT) on the performance of the MEC system was investigated over a period of 110 days. According to the obtained results, the maximum COD removal efficiency in the batch mode was higher than which in the continuous mode (i.e. 85.9% vs 75.3%). However, the maximum methane production in the continuous mode was almost 1.6 times higher than which in the batch mode. The results show, COD removal, methane content, and methane production in both operation modes, were enhanced as applied voltage increased from 0.6 to 0.8-1 V. The proportion of methane, methane production rate, and COD removal were increased as HRT decreased from 72 to 48 h, while these values were decreased as the HRT decreased from 48 to 12 h. In continues mode, the energy efficiency had a range of 94.7% to 97.9% with an average of 96.6% in phase III, which almost recovered all of the electrical energy input into the system. These results suggest that single membrane-less microbial electrolysis cell is a promising process in order to the treatment of low-strength wastewater and methane production.

15.
Food Sci Biotechnol ; 27(6): 1735-1746, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30483438

RESUMEN

Exopolysaccharide (EPS), as potential microbial base polysaccharide source, has plenty of applications due to its unique physicochemical structure. A Pantoea sp. BCCS 001 GH bacterium with the ability to produce a high amount of EPS was identified by 16S rRNA gene sequencing and biochemical tests. The synthesis of EPS by Pantoea sp. BCCS 001 GH was 13.50 g/L in 48 h when sucrose was used as substrate. The proposed protocol was desirably rapid for massive prodcution of EPS and showed the remarkable impact of sucrose and disodium hydrogen phosphate, peptone, Triton x-100 and 2% (v/v) inoculum size on the yields of EPS production. The EPS was mainly composed of glucose and galactose in a relative molar ration (glucose/galactose) of 85.18:14.82, respectively. The preliminary characterization showed the average molecular-weight of EPS is about 2.522 × 106 Da. The microscopics morphology of polymer was formed irregularly shaped structures.

16.
Int J Biol Macromol ; 118(Pt A): 1103-1111, 2018 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-30001597

RESUMEN

The newly discovered exopolysaccharide (EPS) produced by Pantoea sp. BCCS 001 GH, isolated from nectarine fruit and some of its physical properties were characterized. This paper examines precipitation, rheological behavior, emulsification, and antioxidant activities of EPS. Particularly, the concentration of common salt (NaCl) affected on precipitation of EPS; while the low ratio (3 Vagent/V) of CaCl2 isopropanol to culture broth was required. The Zeta potential value of emulsified particles had a high surface charge -65.67 ±â€¯0.6 mV. The strong hydrogen bonds and/or hydrophobic interactions between the polysaccharide and the Congo red molecule showed the triple helical polysaccharide. The water solubility index and water holding capacity of the EPS were 15.6 ±â€¯0.22, 662 ±â€¯12.5%, respectively. The degradation temperature (Td) of 318 °C was observed from the TGA curve for the EPS. The rheological study indicated that the EPS had typically non-Newtonian pseudoplastic behavior. Among the EPS and Tween 80 tested against oils/hydrocarbons, EPS was found to be one the most effective emulsifying agent against kerosene, xylene, hexane and diesel (72.8, 74.5, 68.3 and 81.1%, respectively). It was found that changes in pH (2-12) significantly influenced the emulsification of kerosene and diesel. In vitro antioxidant activity of EPS against hydroxyl, 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH), and superoxide free radicals shown good antioxidant activities. These results indicate the favorable potential of the EPS from strain BCCS 001 GH in food and pharmaceutical fields.


Asunto(s)
Depuradores de Radicales Libres/química , Depuradores de Radicales Libres/aislamiento & purificación , Pantoea/química , Polisacáridos Bacterianos/química , Polisacáridos Bacterianos/aislamiento & purificación , Emulsiones
17.
Int J Biol Macromol ; 108: 250-258, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29191423

RESUMEN

Goldnanoparticle (AuNPs), chitosan (CS), cytochrome c (Cyt c) and Nafion were immobilized on the surface of a gold electrode to form a Nafion/Cyt c/CS-3-Mercaptopropionic acid (MPA)-AuNPs/cysteamine-MPA (SAMs)-Au electrode. The CS-MPA-AuNPs nanocomposite was characterized by UV-vis spectroscopy. Electrochemical behavior of modified electrode was analyzed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and chronoamperometry. Uv-vis results showed that CS-MPA-AuNPs nanocomposite could improve electron transfer between Cyt c and electrode surface and keep the catalytic activity of Cyt c. A pair of well defined and reversible redox peaks could be observed for the modified electrode in a 0.1M phosphate buffer solution (PBS, pH 7.0). The anodic and cathodic peak potentials of Cyt c/CS-MPA-AuNPs/SAMs-Au electrode were at 0.006V and -0.043V (vs. Ag/AgCl), respectively. Particular electrocatalytic activity was shown by Cyt c on CS-MPA-AuNPs layer for nitric oxide (NO) reduction. The relationship between peak current and NO concentration was linear in the range of 1×10-7-21.5×10-7M with a detection limit of 0.45×10-7M (S/N=3).The sensitivity was 0.199µA/µM. The obtained results indicating that the newly developed biosensor was quite selective and stable which was used for accurate and exact detection of NO.


Asunto(s)
Técnicas Biosensibles , Quitosano , Citocromos c/metabolismo , Técnicas Electroquímicas , Enzimas Inmovilizadas , Oro , Óxido Nítrico/análisis , Electrodos , Oro/química , Nanopartículas del Metal , Reproducibilidad de los Resultados , Análisis Espectral
18.
J Environ Health Sci Eng ; 16(2): 257-264, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30728997

RESUMEN

Treatment of industrial wastewater by electrocoagulation (EC) is one of the most efficient methods to remove pollutants. Paper-recycling wastewater is a complex mixture containing toxic and recalcitrant substances, indicating complexity and difficulty of its treatment. The aim of the present study was to assess the effectiveness of paper-recycling wastewater treatment by EC process using aluminum (Al) and iron (Fe) plate electrodes. Removal of chemical oxygen demand (COD), total suspended solids (TSS), color and ammonia from paper-recycling mill effluent was evaluated at various electrolysis times (10-60 min), voltage (4-13 V) and pH (3.5-11). The optimum process conditions for the maximum removal of COD, TSS, color and ammonia from paper-recycling industry wastewater have been found to be pH value of 7, treatment time of 60 min and voltage of 10 V. Under optimum operating conditions, the removal capacities of COD, TSS, color and ammonia were 79.5%, 83.4%, 98.5% and 85.3%, respectively. It can be concluded that EC could be considered as an effective alternative for treatment of paper-recycling wastewater.

19.
Water Sci Technol ; 76(5-6): 1206-1214, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28876262

RESUMEN

The microbial desalination cell (MDC) is known as a newly developed technology for water and wastewater treatment. In this study, desalination rate, organic matter removal and energy production in the reactors with and without desalination function were compared. Herein, a new design of plain graphite called roughened surface graphite (RSG) was used as the anode electrode in both microbial fuel cell (MFC) and MDC reactors for the first time. Among the three type of anode electrodes investigated in this study, RSG electrode produced the highest power density and salt removal rate of 10.81 W/m3 and 77.6%, respectively. Such a power density was 2.33 times higher than the MFC reactor due to the junction potential effect. In addition, adding the desalination function to the MFC reactor enhanced columbic efficiency from 21.8 to 31.4%. These results provided a proof-of-concept that the use of MDC instead of MFC would improve wastewater treatment efficiency and power generation, with an added benefit of water desalination. Furthermore, RSG can successfully be employed in an MDC or MFC, enhancing the bio-electricity generation and salt removal.


Asunto(s)
Fuentes de Energía Bioeléctrica , Grafito/química , Purificación del Agua/métodos , Electricidad , Electrodos , Cloruro de Sodio , Aguas Residuales , Agua/química
20.
Eng Life Sci ; 17(5): 545-551, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-32624799

RESUMEN

Energy harvest from optimized annular single chamber microbial fuel cell (ASCMFC) with novel configuration, which treats chocolate industry wastewater, was investigated. In this study, optimization of operational parameters of the ASCMFC in terms of efficiency water-soluble organic matter reduction and capability of electricity generation was evaluated. During the experiment, effluent from the anode compartment was examined through current and power density curves for variation in temperature and pH, chemical oxygen demand (COD), and turbidity removal, and substrate concentration. The performance analyzed at different temperature ranges such as 25, 30, 35, and 40°C, which showed 88% increase by uprising temperature from 25 to 35°C. The ASCMFC was used to produce electricity by adjusting pH between 5 and 9 at resistance of 100 Ω. Under the condition of pH 7 power density (16.75 W/m3) was highest, which means natural pH is preferred to maximize microbial activities. Wastewater concentration with COD of 700 and 1400 mg/L were investigated to determine its affection on current production. Reduction of current density was observed due to decrease in wastewater concentration. Significant reduction in COD and turbidity of effluent were 91 and 78%, respectively. The coulombic efficiency of 45.1% was achieved.

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