scholarly journals Bioremoval of PVP coated silver nanoparticles using Aspergillus niger: the role of exopolysaccharides

2021 ◽  
Author(s):  
Ola M. Gomaa ◽  
Amar Elrshim ◽  
Anindya Chanda
Keyword(s):  
Silver Nanoparticles ◽  
Aspergillus Niger ◽  
Wastewater Treatment Plants ◽  
Aqueous Media ◽  
Visible Spectrum ◽  
Engineered Nanoparticles ◽  
Ag Nps ◽  
Uv Visible

Abstract The rapidly growing production and applications of Engineered Nanoparticles (ENPs) foresees a concomitant increase in the exposure of humans to their potential toxic effects through accidental release to the environment. Due to the limited and/or contaminated water resources, the need to re-use treated water has become imperative. The present work aims to study the removal of Polyvinylpyrrolidone coated silver nanoparticles (PVP-Ag-NPs) using Aspergillus niger and depict the role of exopolysaccharides in the removal process. Our results show that the majority of PVP-Ag-NPs were attached to fungal pellets. About 74% and 88% PVP-Ag-NPs were removed when incubated with A. niger pellets and exopolysaccharide-induced A. niger pellets, respectively. Ionized Ag decreased by 553 and 1290 fold under the same conditions as compared to stock PVP-Ag-NP. The increase in PVP-Ag-PVP concentrations resulted in an increase in reactive oxygen species (ROS) in 24h. The UV-Visible spectrum shows the disappearance of Ag characteristic peak and the broadness of the spectrum suggested an increase in size. Dynamic Light Scattering results showed an increase in PVP-Ag-NPs size from 28.4 nm to 115.9 nm for A. niger pellets and 160.3 nm after removal by stress-induced A. niger pellets and further increased to 650.1 nm for in vitro EPS removal. Our findings show that EPS can be used for nanoparticle removal, by increasing the net size of nanoparticles in aqueous media, this will, in turn, facilitate its filtration through conventional filtration techniques commonly used at wastewater treatment plants.

scholarly journals Bioremoval of PVP coated silver nanoparticles using Aspergillus niger: the role of exopolysaccharides

2021 ◽  
Author(s):  
Ola M. Gomaa ◽  
Amar Alrshim ◽  
Anindya Chanda
Keyword(s):  
Silver Nanoparticles ◽  
Aspergillus Niger ◽  
Wastewater Treatment Plants ◽  
Aqueous Media ◽  
Visible Spectrum ◽  
Ag Nps ◽  
Characteristic Peak ◽  
Uv Visible

Abstract The present work aims to study the removal of Polyvinylpyrrolidone coated silver nanoparticles (PVP-Ag-NPs) using Aspergillus niger and depict the role of exopolysaccharides in the removal process. Our results show that the majority of PVP-Ag-NPs were attached to fungal pellets. About 74% and 88% PVP-Ag-NPs were removed when incubated with A. niger pellets and exopolysaccharide-induced A. niger pellets, respectively. Ionized Ag decreased by 553 and 1290 fold under the same conditions as compared to stock PVP-Ag-NP. PVP-Ag-PVP resulted in an increase in reactive oxygen species (ROS) in 24h. The UV-Visible spectrum shows the disappearance of Ag characteristic peak and the broadness of the spectrum suggested an increase in size. Dynamic Light Scattering results showed an increase in PVP-Ag-NPs size from 28.4 nm to 115.9 nm for A. niger pellets and 160.3 nm after removal by stress-induced A. niger pellets and further increased to 650.1 nm for in vitro EPS removal. Our findings show that EPS can be used for nanoparticle removal, by increasing the net size of nanoparticles in aqueous media, this will, in turn, facilitate its filtration through conventional filtration techniques commonly used at wastewater treatment plants.

scholarly journals Green Synthesis of Silver Nanoparticles Using Flower Extract of Hemigraphis colorata as Reducing Agent and its Biological Activity

2021 ◽  
Vol 10 (4) ◽  
pp. 2646-2654
Keyword(s):  
Silver Nanoparticles ◽  
Electron Microscope ◽  
Green Synthesis ◽  
Visible Spectrum ◽  
Spherical Shape ◽  
Ag Nps ◽  
Surface Plasma Resonance ◽  
Flower Extract ◽  
Uv Visible ◽  
Average Size

Green synthesis of silver nanoparticles (Ag NPs) was performed using flower extract of Hemigraphis colorata (H. Colorata). Synthesized nanoparticles were characterized by UV-Visible Spectrophotometer (UV-Vis), Fourier Transform Infrared (FT-IR), Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM-SAED). , The crystalline nature of the sample was examined by an X-ray diffraction study (XRD). The UV-Visible spectrum showed surface plasma resonance (SPR) at 360 nm revealed the formation of nanoparticles, SEM and TEM exhibited spherical shape particles with an average size between 10-20 nm. The valuation of the antibacterial and antifungal study revealed its efficiency in killing bacteria and fungi.

scholarly journals Green Fabrication of Silver Nanoparticles using Euphorbia serpens Kunth Aqueous Extract, Their Characterization, and Investigation of Its In Vitro Antioxidative, Antimicrobial, Insecticidal, and Cytotoxic Activities

2022 ◽  
Vol 2022 ◽  
pp. 1-11
Author(s):  
Nisar Ahmad ◽  
Fozia ◽  
Musarrat Jabeen ◽  
Zia Ul Haq ◽  
Ijaz Ahmad ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Aqueous Extract ◽  
Visible Spectrum ◽  
Artemia Salina ◽  
Metallic Silver ◽  
Cytotoxic Activities ◽  
Zone Of Inhibition ◽  
Tem Analysis ◽  
Uv Visible

The silver nanoparticles (AgNPs) were synthesized via green synthesis approach using Euporbia serpens Kunth aqueous extract. The synthesized AgNPs were characterized by UV-visible spectroscopy and Furrier Transformer Infra-Red spectroscopy to justify the reduction and stabilization of AgNPs from its precursors. AgNPs characteristic absorption peak was observed at 420 nm in the UV-visible spectrum. The SEM and TEM analysis demonstrated the spherical shape of the synthesized nanoparticles with particle sizes ranging from 30 nm to 80 nm. FTIR transmission bands at 2920 cm-1, 1639 cm-1, 1410 cm-1, 3290 cm-1, and 1085 cm-1 were attributed to C-H, C=O, C-C, N-H, and C-N functional groups, respectively. XRD peaks could be attributed to (111), (200), (220), and (311) crystalline plane of the faced-centered cube (FCC) crystalline structure of the metallic silver nanoparticles. The AgNPs showed good antibacterial activity against all the tested bacteria at each concentration. The particles were found to be more active against Escherichia coli (E. coli) with 20 ± 06   mm and Salmonella typhi (S. typhi) with 18 ± 0.5   mm zone of inhibition in reference to standard antibiotic amoxicillin with 23 ± 0.3   mm and 20 ± 0.4   mm zone of inhibition, respectively. Moderate antifungal activities were observed against Candida albicans (C. albicans) and Alternaria alternata (A. alternata) with zone of inhibitions 16.5 mm and 15 mm, respectively, compared to the standard with 23 mm of inhibition. Insignificant antifungal inhibition of 7.5 mm was observed against Fusarium gramium (F. gramium). All the tested concentrations of AgNPs showed comparable % RSA with the standard reference ascorbic acid in the range sixty percent to seventy five percent. The percent motility at 3 hours postincubation showed quick response and most Tetramorium caespitum were found deceased or paralyzed. Similarly, the percent mortality showed a linear response at concentration and time. It was observed that 1 μg/mL to 2 μg/mL concentration of AgNPs displayed a significant cytotoxic activity against Artemia salina with LD50 of 5.37 and 5.82, respectively.

Phytochemical Preparation, Characterization and Photocatalytic Applications of Ag-TiO2 Nanocatalyst

2015 ◽  
Vol 1086 ◽  
pp. 1-6 ◽  
Author(s):  
P. Yuvasree ◽  
K. Nithya ◽  
N. Neelakandeswari ◽  
N. Rajasekaran ◽  
K. Uthayarani ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Rhodamine B ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
Ag Nps ◽  
X Ray ◽  
Chemical Approach ◽  
Uv Visible ◽  
Photocatalytic Applications

Green chemical approach is adopted for the synthesis of silver nanoparticles (Ag NPs). Since the nanoparticles tend to aggregate during the course of the catalytic reaction, they need to be stabilized by employing a suitable template or a support. Hence the prepared nanoparticles were loaded on titania support and used as a photocatalyst. Silver loaded titania (Ag-TiO2) is characterized by UV-visible spectroscopy, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS). Prepared composite was also tested for its photocatalytic activity against the degradation of an industrial pollutant Rhodamine B dye. Effect of pH, ratio between the catalyst and the substrate and also the role of free radical generator in the degradation have been tested and summarized in this work.Keywords: Silver nanoparticles, Phytochemical preparation, Green chemical approach, Photocatalysis, Rhodamine B

Liquid-liquid extraction of succinate using a dicopper cryptate

2020 ◽  
Author(s):  
Riccardo Mobili ◽  
Sonia La Cognata ◽  
Francesca Merlo ◽  
Andrea Speltini ◽  
Massimo Boiocchi ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Visible Spectrum ◽  
Tca Cycle ◽  
Residual Concentration ◽  
Waste Products ◽  
Liquid Liquid Extraction ◽  
The Tca Cycle ◽  
Quantitative Extraction ◽  
Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

Preparation of Triangular Silver Nanoparticles Using Polyvinyl Pyrrolidone with Different Concentration

2013 ◽  
Vol 873 ◽  
pp. 206-210
Author(s):  
Kai Li ◽  
Rao Fu ◽  
Qing Ran Gao ◽  
Ai Wei Tang ◽  
Ying Feng Wang
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Silver Nanoparticles ◽  
Driving Force ◽  
Ostwald Ripening ◽  
Polyvinyl Pyrrolidone ◽  
Protective Agent ◽  
Ag Nps ◽  
Transmission Electron ◽  
Uv Visible

This paper continues our previous work on preparation of triangular silver nanoparticles. The method proceeds with reaction of silver nitrate with hydrazine hydrate in the presence of polyvinyl pyrrolidone in aqueous solution. Effects of the concentration of PVP on the morphologies of Ag NPs were systematically investigated. The obtained Ag NPs were characterized by transmission electron microscopy and UV-visible spectrophotometer. The results showed that, triangular Ag NPs with edge lengths in the range of 50-200 nm were obtained using PVP as protective agent with lower concentration. As the concentration of PVP increased, spherical Ag NPs with their sizes about 6.2 nm were prepared and triangular Ag NPs were not obtained. The formation mechanism of triangular Ag NPs has been studied. Ostwald ripening is the driving force on the conversion of spherical Ag NPs to triangular Ag NPs in the presence of PVP.

Functionalized silver nanoparticles synthesized from marine algae: In vitro Evaluation of Antibacterial Potential

2021 ◽  
Vol 16 (8) ◽  
pp. 38-49
Author(s):  
Siva Kumar Kandula ◽  
Satyanarayana Swamy Cheekatla ◽  
Venkata Satya Mahesh Kumar Metta ◽  
Venkata Rajagopal Saladi
Keyword(s):  
Silver Nanoparticles ◽  
Antioxidant Activities ◽  
Algal Species ◽  
Synthesis Method ◽  
Radical Scavenging ◽  
Visible Spectrum ◽  
Total Phenolic ◽  
Face Centered Cubic ◽  
Frap Assay

Natural antioxidants, in particular phenolic derivatives, are used efficiently to combat against oxidative induced tissue damages. The objective of the study is to determine the antioxidant potential of methanolic extracts obtained from eight marine algal species (Enteromorpha compressa, Chaetomorpha antennina, Caulerpa racemosa, Caulerpa taxifolia, Sargassum vulgare, Padina tetrastromatica, Amphiroa fragilissima and Gracilaria corticata) by assessing their total phenolic content, DPPH scavenging assay, FRAP assay, H2O2 radical and superoxide radical scavenging activities. Among them, P.tetrastromatica, S.vulgare, E.compressa, C.taxifolia display significant antioxidant activities. Further, the aqueous extracts of these four algae are used for bioreduction of silver nitrate to silver nanoparticles (AgNPs) by green synthesis method at room temperature. UV-Visible spectrum revealed the surface plasmon resonance at 430 and 440nm. The characterizations of AgNPs by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies revealed the bioreduction and capping of AgNPs. XRD analysis elucidated the synthesized nanoparticles having face centered cubic crystalline geometry, with a mean size of 17 nm. The nanoparticles have better antimicrobial activity against cocci shaped than the rod shaped bacteria. The minimum inhibitory concentration and minimum bactericidal concentration exhibit more activity against S.aureus and B.cereus rather than E.coli.

scholarly journals Liquid-liquid extraction of succinate using a dicopper cryptate

2020 ◽  
Author(s):  
Riccardo Mobili ◽  
Sonia La Cognata ◽  
Francesca Merlo ◽  
Andrea Speltini ◽  
Massimo Boiocchi ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Visible Spectrum ◽  
Tca Cycle ◽  
Residual Concentration ◽  
Waste Products ◽  
Liquid Liquid Extraction ◽  
The Tca Cycle ◽  
Quantitative Extraction ◽  
Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

scholarly journals Nanocatalytic Activity of Silver Nanoparticles (Ag-Nps) Fabricated using Camellia sinensis (Linn) Tender Leaf Extract and their Characterization

2020 ◽  
Vol 2 (1) ◽  
pp. 24
Keyword(s):  
Silver Nanoparticles ◽  
Zeta Potential ◽  
Pancreatic Enzyme ◽  
Alpha Amylase ◽  
Assay Method ◽  
Ag Nps ◽  
Visible Absorption ◽  
Biological Reduction ◽  
Vis Spectroscopy ◽  
Uv Visible

Silver nanoparticles (Ag-NPs) were prepared by the biological reduction method. Green tea extract was taken as a reducing and stabilizing agent and silver nitrate as the metal precursor for nanoparticle synthesis. The formation of the silver nanoparticles was monitored visually and using UV-Visible absorption spectroscopy. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, FTIR, Zeta sizer, Zeta potential, and antimicrobial studies. Silver nanoparticles were also subjected to investigate nanocatalytic activity with standard pancreatic alpha-amylase and bacterial amylase enzyme by the DNS assay method. UV-Vis spectroscopy revealed the formation of silver nanoparticles by exhibiting the typical surface plasmon absorption maxima at 430 nm. Four major functional groups of bio-molecules such as phenol, carboxylic acid, protein, and alkyl group were recorded in FTIR spectra. The size of the nanoparticles ranges between 5nm and 150nm. The average size and size distribution of silver nanoparticles is 59.66nm. The zeta potential of the silver nanoparticle is negatively charged and rendered as a sharp peak at -31.7mV. Antimicrobial activity of silver nanoparticles exhibited the highest inhibition against Gram-negative bacteria than Gram-positive bacteria and yeast pathogens. Starch hydrolysis of Ag-NPs was studied with pancreatic alpha-amylase (tailor made), crude and purified bacterial amylase enzyme. The formation of reducing sugar was increased about 40-fold for a purified enzyme, 11-fold for the pancreatic enzyme, and 6-fold for crude bacterial enzyme incorporated with Ag-NPs over control. The present studies recommended that Ag-NPs have a significant role in the degradation of starch into reducing sugars by acting as a nanocatalyst.

Optimization of Silver Nanoparticles Production using Aspergillus niger and Study of Antimicrobial Activity

2021 ◽  
Vol 12 (4) ◽  
pp. 2383-2388
Author(s):  
Suguna Selvakumaran ◽  
Kayathri Marimuthu ◽  
Thiruvany Poopalan ◽  
Kalaiyarasi Tamil Selvan ◽  
Nozieana Khairuddin
Keyword(s):  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Aspergillus Niger ◽  
Culture Supernatant ◽  
Gram Negative Bacteria ◽  
Mixing Ratio ◽  
Zone Of Inhibition ◽  
Gram Positive Bacteria ◽  
Physiochemical Parameters ◽  
Uv Visible

Silver nanoparticles have attracted high attention worldwide for their various applications. The physiochemical parameters such as temperature, media, mixing ratio affect the rate of synthesis of silver nanoparticles and their yield. Thus, optimization of these physiochemical parameters is needed to enhance the production of silver nanoparticles. In this study, silver nanoparticles were synthesized using Aspergillus niger culture supernatant. The produced silver nanoparticles were characterized using UV-visible Spectrophotometer at 200 nm to 700 nm, which had a peak at 450 nm, indicates the formation of silver nanoparticles. It was found that Sabouraud Dextrose Broth (SDB) as optimum media, 40 ml of supernatant and 10 ml of silver nitrate as optimum mixing ratio and 65°C as optimum temperature to produce silver nanoparticles. The optimized silver nanoparticles were subjected to antimicrobial activity, and it was found that it is highly effective towards gram-negative bacteria than gram-positive bacteria where the zone of inhibition for Escherichia coli was  7 ± 2.7 mm and 5.3 ± 2.1 mm for Staphylococcus aureus.

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