| 1. |
- Noshad, Asma, et al.
(författare)
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Antibacterial Effect of Silver Nanoparticles (AgNPs) Synthesized from Trichoderma Harzianum Against Clavibacter Michiganensis
- 2019
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Ingår i: Journal of Nano Research. - 1662-5250 .- 1661-9897. ; 58, s. 10-19
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Tidskriftsartikel (refereegranskat)abstract
- In nanotechnology, fungal mediated green synthesis of silver nanoparticles (AgNPs) has tremendous application in the development of antimicrobial systems but the mechanism behind the synthesis is yet to be understood. This study aims to synthesize the silver nanoparticles via a green chemistry route using mycellial aqueous extract of agriculturally beneficial fungi Trichoderma harzianum. Two different concentrations (1 mM and 2.5 Mm) of aqueous silver salt (AgNO3) were used and mixed as 1:1 ratio with aqueous extract of T. harzianum at room temperature and the pH of the reaction mixture was monitored until it stabilized. Formation of AgNPs was confirmed by using UV-Vis spectroscopic analysis. For further insight, AgNPs were characterized by using HR-TEM and XRD, which clearly showed appearance of crystalline, monodispersed round-shaped particles of 3-20 nm in size. The synthesised NPs were subjected to antimicrobial assay against gram +ve and gram –ve bacteria using the disk diffusion method. The focused species was Clavibacter michiganensis subsp michiganensis, which is the causitive pathogen of Tomato canker disease and we hypothesised that the synthesised AgNPs might be useful to control this pathogen. Appreciable antibiotic activity was monitored even at a low concentration of 1mM level, while the zone of inhibition was positively increased at 2.5 mM. Our results clearly indicate that the present process is an excellent candidate for industrial scale production of AgNPs, and has the potential to control the bacterial pathogen cmm.
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| 2. |
- Noshad, Asma, et al.
(författare)
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Impact of AgNPs on seed germination and seedling growth : A focus study on its antibacterial potential against clavibacter michiganensis subsp. Michiganensis infection in solanum lycopersicum
- 2019
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Ingår i: Journal of Nanomaterials. - : Hindawi Limited. - 1687-4110 .- 1687-4129. ; 2019
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effect of biogenic AgNPs on seed germination and seedling growth of Solanum lycopersicum. Treatment with silver nanoparticles (AgNPs) showed a significantly high germination rate and seedling growth compared to untreated seeds. Furthermore, its bactericidal effect against bacterial pathogen Clavibacter michiganensis subsp. michiganensis (cmm) infection in Solanum lycopersicum was also determined. Bacterial canker of tomato (BCT) caused by cmm results in reduced plant growth and production leading to considerable economic losses. Herein, fungal extracts of T. harzianum and A. fumigatus were used separately as a reducing agent to synthesize AgNPs of varying concentrations (0.088 mg/L, 0.176 mg/L, and 0.44 mg/L). Results suggested that the biosynthesized AgNPs not only worked as bactericide but also completely inhibited the incidence of cmm infection even at the lowest concentration of 0.088 mg/L under greenhouse conditions. Plants treated with AgNPs showed significantly enhanced growth parameters including plant height (cm), tomato yield/plant (g), fresh biomass (g), number of shoots/plant, root weight (g), and dry biomass (g). So, in order to reduce the toxic effects of chemical-based bactericides, biobased AgNPs are recommended, not only to control but also to prevent the bacterial infection in agriculture.
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| 3. |
- Quiroga Flores, Roxana, et al.
(författare)
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Adsorption of cadmium by a high-capacity adsorbent composed of silicate-titanate nanotubes embedded in hydrogel chitosan beads
- 2020
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Ingår i: Environmental Technology. - : Informa UK Limited. - 1479-487X .- 0959-3330. ; 41:23, s. 3043-3054
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we developed a nanoparticle-based mesoporous composite that consisted of silicate-titanate nanotubes (STNTs) supported in hydrogel chitosan beads (STNTs-Ch beads) and was studied for Cd2+ adsorption. By using Fourier-transform infrared spectroscopy, transmission and scanning electron microscopy coupled to an energy-dispersive X-ray spectrometer, we coulddetermine that the hollow STNTs were highly dispersed in the walls of the hollow beads. The dispersion was attributed to the effect of pH when the composite was prepared and we observed a non-interaction between STNTs and chitosan. The adsorption studies of Cd2+ showed that the kinetic rate (k2) increased 3-fold and that the diffusion rate (Kd) increased 2-fold afterthe embedment. Moreover, the maximum capacity of adsorption of STNTs-Ch beads was 2.3 times higher than that of STNTs alone. The treatment of a synthetic Cd2+ solution and a real leachate in continuous mode showed two phases in which it was observed higher removed fractions of transition metal ions (Cd2+, Co2+, Ni2+, Zn2+ and Cu2+) and the post-transition metal ion Pb2+, in comparison to the removed fractions of alkali and alkali-earth metal ions (Ca2+, K+, Mg2+). The composite was successfully reused four times when adsorbing Cd2+, saving three times the needed amounts of TiO2, SiO2 and chitosan for the production of the material. This composite was produced in a simple way and shows the potential for wastewater treatment.
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