Extraction of extracellular polymeric substances from the acidophilic bacterium Acidiphilium 3.2Sup(5)

2009 ◽  
Vol 59 (10) ◽  
pp. 1959-1967 ◽  
Author(s):  
J. M. Tapia ◽  
J. A. Muñoz ◽  
F. González ◽  
M. L. Blázquez ◽  
M. Malki ◽  
...  
Keyword(s):  
Microbial Fuel Cells ◽  
Extracellular Polymeric Substances ◽  
Ion Exchange Resin ◽  
Before And After ◽  
Acidophilic Bacterium ◽  
Ft Ir ◽  
Promising Application ◽  
Microscopy Techniques ◽  
Graphite Rods ◽  
Cellular Lysis

Extraction of extracellular polymeric substances (EPS) from Acidiphilium 3.2Sup(5) was investigated using five methods: EDTA, NaOH, ion exchange resin, heating and centrifugation. The bacterium studied presents promising application in microbial fuel cells (MFCs). The degree of cellular lysis provoked by each method was determined by UV-visible spectroscopy of cultures before and after EPS extraction. In addition, two electron microscopy techniques (TEM and SEM) were employed to determine the degree of attachment and the growth of the biofilm overtime on two solid supports: carbon fibre cloth and graphite rods. The main constituents of the EPS extracted by all methods were proteins and carbohydrates, as confirmed by FT-IR analysis, showing the major presence of carboxylic, hydroxylic and amino groups. The greater extractions of EPS were obtained using EDTA. This method also produced a less degree of cellular lysis. Furthermore, both the amount and the chemical composition of EPS strongly depended on the extraction method used.

Interrelation between Cells and Extracellular Polymeric Substances (EPS) from Acidiphilium 3.2Sup(5) on Carbon Surfaces

2009 ◽  
Vol 71-73 ◽  
pp. 287-290 ◽  
Author(s):  
Jaime M. Tapia ◽  
J.A. Muñoz ◽  
F. González ◽  
M. Luisa Blázquez ◽  
Antonio Ballester
Keyword(s):  
Ftir Spectroscopy ◽  
Microbial Fuel Cells ◽  
Extracellular Polymeric Substances ◽  
Great Majority ◽  
Chemical Analyses ◽  
Acidophilic Bacterium ◽  
Carbon Surfaces ◽  
Main Components ◽  
Graphite Rods

The interrelation between cells and extracellular polymeric substances (EPS) from the acidophilic bacterium Acidiphilium 3.2Sup(5) was investigated on two different carbon surfaces (carbon fibre cloth and graphite rods). This bacterium was chosen due to its ability to directly transfer electrons to carbon surfaces in aerobic conditions, which makes its use especially attractive in microbial fuel cells (MFC). The characterization of the bacterial adhesion and interrelation with the EPS was carried out using a combination of scanning (SEM) and transmission (TEM) electron microscopy. The extraction of the EPS was performed using EDTA and their characterization accomplished by chemical analyses and FTIR spectroscopy. The cellular lysis provoked by the extraction of EPS was determined by the protein/carbohydrate ratio. Chemical analyses showed that the main components of the EPS were proteins and carbohydrates, whereas FTIR spectroscopy showed the presence of a great majority of carboxyl, hydroxyl and amino groups. The tendency of cells was to adhere to superficial carbon imperfections, which after certain time were covered by a matrix of EPS.

scholarly journals Biofilm Formation in Xanthomonas arboricola pv. pruni: Structure and Development

Agronomy ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 546
Author(s):  
Pilar Sabuquillo ◽  
Jaime Cubero
Keyword(s):  
Biofilm Formation ◽  
Extracellular Polymeric Substances ◽  
Environmental Changes ◽  
Nutrient Content ◽  
Infection Process ◽  
Bacterial Attachment ◽  
Key Factors ◽  
Cell Structures ◽  
Microscopy Techniques

Xanthomonasarboricola pv. pruni (Xap) causes bacterial spot of stone fruit and almond, an important plant disease with a high economic impact. Biofilm formation is one of the mechanisms that microbial communities use to adapt to environmental changes and to survive and colonize plants. Herein, biofilm formation by Xap was analyzed on abiotic and biotic surfaces using different microscopy techniques which allowed characterization of the different biofilm stages compared to the planktonic condition. All Xap strains assayed were able to form real biofilms creating organized structures comprised by viable cells. Xap in biofilms differentiated from free-living bacteria forming complex matrix-encased multicellular structures which become surrounded by a network of extracellular polymeric substances (EPS). Moreover, nutrient content of the environment and bacterial growth have been shown as key factors for biofilm formation and its development. Besides, this is the first work where different cell structures involved in bacterial attachment and aggregation have been identified during Xap biofilm progression. Our findings provide insights regarding different aspects of the biofilm formation of Xap which improve our understanding of the bacterial infection process occurred in Prunus spp and that may help in future disease control approaches.

scholarly journals Fast Preparation of High-Performance Wood Materials Assisted by Ultrasonic and Vacuum Impregnation

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 567
Author(s):  
Hong Yang ◽  
Mingyu Gao ◽  
Jinxin Wang ◽  
Hongbo Mu ◽  
Dawei Qi
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
Mechanical Tests ◽  
Vacuum Impregnation ◽  
Natural Forests ◽  
Ultrasonic Pretreatment ◽  
Fast Growing ◽  
Before And After ◽  
New Material ◽  
Ft Ir

In the absence of high-quality hardwood timber resources, we have gradually turned our attention from natural forests to planted fast-growing forests. However, fast-growing tree timber in general has defects such as low wood density, loose texture, and poor mechanical properties. Therefore, improving the performance of wood through efficient and rapid technological processes and increasing the utilization of inferior wood is a good way to extend the use of wood. Densification of wood increases the strength of low-density wood and extends the range of applications for wood and wood-derived products. In this paper, the effects of ultrasonic and vacuum pretreatment on the properties of high-performance wood were explored by combining sonication, vacuum impregnation, chemical softening, and thermomechanical treatments to densify the wood; then, the changes in the chemical composition, microstructure, and mechanical properties of poplar wood before and after treatment were analyzed comparatively by FT-IR, XRD, SEM, and mechanical tests. The results showed that with ultrasonic pretreatment and vacuum impregnation, the compression ratio of high-performance wood reached its highest level and the MOR and MOE reached their maximums. With the help of this method, fast-growing softwoods can be easily prepared into dense wood materials, and it is hoped that this new material can be applied in the fields of construction, aviation, and automobile manufacturing.

scholarly journals Structural Investigations on Poly(methyl methacrylate) Various Composites Used for Stereolithographyc Complete Dentures

2018 ◽  
Vol 55 (4) ◽  
pp. 616-619 ◽  
Author(s):  
Eugenia Eftimie Totu ◽  
Corina Marilena Cristache ◽  
Selim Isildak ◽  
Ozlem Tavukcuoglu ◽  
Aida Pantazi ◽  
...  
Keyword(s):  
Titanium Oxide ◽  
Material Characterization ◽  
Polymeric Matrix ◽  
Structural Behavior ◽  
Oxide Nanoparticles ◽  
Complete Dentures ◽  
Titanium Oxide Nanoparticles ◽  
Structural Investigations ◽  
Ft Ir ◽  
Microscopy Techniques

The present paper is focused on analyzing if appropriate adhesion between the polymeric matrix and titania filler nanoparticles is obtained for the PMMA-TiO2 photo-curable dental material, suitable for application in RP - stereolithography (SLA) for complete denture manufacturing. It was found that different amounts, between 0.2% and 2.5 % (w/w%), of added titanium oxide nanoparticles slightly modify the structural behavior of the PMMA polymeric matrix. The material characterization was carried out using FT-IR and microscopy techniques.

scholarly journals Newly Synthesized N-Substituted Thiosemicarbazone as a Potential Corrosion Inhibitor for Mild Steel in 1 M HCl

2019 ◽  
Vol 7 (4.14) ◽  
pp. 168
Author(s):  
N Z. Nor Hashim ◽  
K Kassim ◽  
F H. Zaidon
Keyword(s):  
Mild Steel ◽  
Corrosion Inhibitor ◽  
Potentiodynamic Polarization ◽  
Corrosion Inhibitors ◽  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Langmuir Adsorption ◽  
Before And After ◽  
Ft Ir ◽  
L1 And L2

Two N-substituted thiosemicarbazone derivatives namely as 2-(4-chlorobenzylidene)-N-phenylhydrazinecarbothioamide and 2-benzylidene-N-phenylhydrazinecarbothioamide (L1 and L2, respectively) have been tested as corrosion inhibitors on mild steel in 1 M HCl. The ligands were synthesized and investigated using potentiodynamic polarization (PD) and electrochemical impedance spectroscopy (EIS).  The obtained results indicated that inhibition efficiency, (IE, %) L1 increased with increasing inhibitor concentrations which behaved as a good corrosion inhibitor compared to L2. The synthesized ligands were successfully characterized by melting point, elemental analysis (C, H, N, and S), Fourier-transform infrared spectroscopy (FT-IR) and NMR (1H and 13C) spectroscopy. The excellent inhibition effectiveness for both compounds on mild steel before and after immersion in 1 M HCl solution containing 40 ppm of L1 and L2 were also verified by scanning electron microscope (SEM). Based on potentiodynamic polarization results, it can be concluded that all investigated compounds are mixed-type inhibitors and obey the Langmuir adsorption isotherm. 

scholarly journals Degradable Polymer Stars Based on Tannic Acid Cores by ATRP

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 752 ◽  
Author(s):  
Julia Cuthbert ◽  
Saigopalakrishna S. Yerneni ◽  
Mingkang Sun ◽  
Travis Fu ◽  
Krzysztof Matyjaszewski
Keyword(s):  
Tannic Acid ◽  
Molar Mass ◽  
Gel Permeation Chromatography ◽  
Degradable Polymers ◽  
Degradable Polymer ◽  
Cytotoxicity Assays ◽  
Before And After ◽  
Phenolic Esters ◽  
Ft Ir ◽  
Waste Accumulation

Degradable polymers are crucial in order to reduce plastic environmental pollution and waste accumulation. In this paper, a natural product, tannic acid was modified to be used as a polymer star core. The tannic acid was modified with atom transfer radical polymerization (ATRP) initiators and characterized by 1H NMR, FT-IR, and XPS. Twenty-five arm polymer stars were prepared by photoinduced ATRP of poly(methyl methacrylate) (PMMA) or poly(oligo(ethylene oxide) methacrylate) (molar mass Mw = 300 g/mol) (P(OEO300MA)). The polymer stars were degraded by cleaving the polymer star arms attached to the core by phenolic esters under mild basic conditions. The stars were analyzed before and after degradation by gel permeation chromatography (GPC). Cytotoxicity assays were performed on the P(OEO300MA) stars and corresponding degraded polymers, and were found to be nontoxic at the concentrations tested.

scholarly journals Application of a Terephthalate and Pyrazine-Based MOF in Cr Adsorption

Proceedings ◽  
2019 ◽  
Vol 41 (1) ◽  
pp. 60
Author(s):  
Zahra Rezaee ◽  
Faranak Manteghi
Keyword(s):  
Metal Organic Framework ◽  
Ultrasonic Method ◽  
Chromium Concentration ◽  
Donor Ligands ◽  
Nitrogen Donor Ligands ◽  
Nickel Ions ◽  
Nitrogen Donor ◽  
Before And After ◽  
Metal Organic ◽  
Ft Ir

In this study, a terephthalate and pyrazine-based metal–organic framework (MOF) was prepared using the oxygen and nitrogen donor ligands through the hydrothermal method. In the MOF, cobalt and nickel ions were selected as metal nodes which are connected by terephthalate and pyrazine linkers. The as-prepared MOF was utilized as Cr adsorbent in water by an ultrasonic method. The MOF capacity towards chromium ion adsorption was obtained about 96% in 50 ppm initial concentration. In order to characterize and determine the morphology of the title MOF, the FT-IR and XRD methods were applied, while the chromium concentration before and after adsorption was determined by the ICP method.

scholarly journals Synthesis of epoxy resins derivatives of naphthalene-2,7-diol and their cross-linked products

2019 ◽  
Vol 138 (6) ◽  
pp. 4349-4358 ◽  
Author(s):  
K. Fila ◽  
M. Gargol ◽  
M. Goliszek ◽  
B. Podkościelna
Keyword(s):  
Fourier Transform ◽  
Epoxy Resins ◽  
Attenuated Total Reflectance ◽  
Cross Linking ◽  
Total Reflectance ◽  
Before And After ◽  
Ft Ir ◽  
The Cross ◽  
Derivatives Of ◽  
Epoxy Groups

Abstract The aim of this study was the synthesis of three different epoxy compounds based on naphthalene-2,7-diol (2,7-NAF.EP, 2,7-NAF.WEP, 2,7-NAF.P.EP) and then their cross-linking by triethylenetetramine (TETA). All epoxides were prepared by the reaction of naphthalene-2,7-diol with epichlorohydrin but under different conditions and with other catalysts. The structures of the obtained compounds before and after the cross-linking reactions were confirmed by the attenuated total reflectance Fourier transform infrared spectroscopy (ATR/FT-IR). The ATR/FT-IR spectra of cross-linked compounds show disappearance of the C–O–C bands (about 915 cm−1) derived from the epoxy groups. DSC and TG/DTG measurements indicated that the obtained materials possess good thermal resistance; they are stable up to about 250 °C. The hardness of the cross-linked products was determined using the Shore D method. The highest value of hardness was obtained for the 2,7-NAF.EP-POL. Additionally, the UV–Vis absorption spectra of the obtained polymers were registered and evaluated.

scholarly journals Esterification of Cochineal Carmine Used for Dyeing Cationic Modified Cotton with High Color Fastness

2017 ◽  
Vol 12 (2) ◽  
pp. 155892501701200
Author(s):  
Yan Luo ◽  
Mengya Li ◽  
Juan Du
Keyword(s):  
Sodium Acetate ◽  
Color Fastness ◽  
Structure And Properties ◽  
Binding Agent ◽  
Light Fastness ◽  
Ir Spectrometry ◽  
Vis Spectroscopy ◽  
Before And After ◽  
Ft Ir ◽  
Cloud Density

In order to reduce the electronic cloud density for higher color fastness, ester groups were introduced into cochineal carmine matrix structure. The optimum esterification conditions were selected by varying the level of acid-binding agent, the reaction temperature, the reaction time, and the amount of acetylation reagent. The structure and properties of esterified cochineal carmine was characterized by UV-vis spectroscopy, FT-IR spectrometry and metallographic microscopy. The build-up property, dyeability, light fastness, perspiration and rubbing fastness of cochineal carmine before and after esterification on cationic modified cotton were investigated. The results show that the optimum esterification condition is treating 1.0 g cochineal carmine with 50 mL acetic anhydride and 4.0 g anhydrous sodium acetate at 80°C for 2.0 hours. The acid perspiration fastness and wet rubbing fastness of the resulting dyed samples were increased by one grade. The perspiration fastness to alkalis and the light fastness were improved by one-half grade.

Kinetics of azoreductase and assessment of toxicity of metabolic products from azo dyes by Pseudomonas luteola

2001 ◽  
Vol 43 (2) ◽  
pp. 261-269 ◽  
Author(s):  
T.-L. Hu
Keyword(s):  
Azo Dyes ◽  
Competitive Inhibition ◽  
Orthanilic Acid ◽  
Metabolic Products ◽  
Before And After ◽  
Ft Ir ◽  
Ir Analysis ◽  
Pseudomonas Luteola ◽  
Monoazo Dyes ◽  
Kinetics Of

This is a continuous study on a decolorization strain, Pseudomonas luteola, which involves treating seven azo dyes with different structures. This study focuses mainly on determining both the mechanism of decolorization by P. luteola and the activity of azoreductase from P. luteola as well as identifying and assessing the toxicity of metabolic products of azo dyes. The growth of P. luteola reached the stationary phase after shaking incubation for 24 hours. Then, while being kept static, the color of seven tested azo dyes (100 mg/l) could be removed. The proportion of color removal was between 59–99%, which figure is related to the structure of the dye. Monoazo dyes (RP2B, V2RP and Red 22) showed the fastest rate of decolorization, i.e. from 0.23–0.44 mg dye-mg cell–1 hr–1. P. luteola could remove the color of V2RP and a leather dye at a concentration of 200 mg/l, and as to the rest of the azo dyes, it could remove at a concentration of up to 100 mg/l. Decolorization of RP2B and Red 22 required activation energy of 7.00 J/mol and 6.63 J/mole, respectively, indicating that it was easier for azoreductase to decolorize structurally simple dyes. The kinetics of azoreductase towards seven azo dyes suggested a competitive inhibition model be applied. Microtox® was used to analyze the toxicity of the metabolic products of azo dyes. EC50 showed differences in toxicity before and after the azo dyes had been metabolized. Analysis revealed significant differences between the results obtained by EC50 with Blue 15 and those obtained with the leather dye, indicating that the toxicities of the metabolic products were increased. The differences obtained by EC50 with Red 22, RP2P and V2RP were small, and Black 22 showed no such difference. Sulfanic acid and orthanilic acid may be the intermediate products of Violet 9 and RP2B, respectively. However, according to FT-IR analysis, aromatic amines were present in the metabolic product.

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