A novel photocatalytic degradation of mixed dye through chemically synthesized ZnO/Fe2O3 nanocomposite.

This study reported the synthesis and assessment of zinc oxide/iron oxide (ZnO/Fe2O3) nanocomposite as photocatalysts for the degradation of a mixture of methylene red and methylene blue dyes. X-ray diffraction analysis confirms that the crystallite of zinc oxide (ZnO) has a hexagonal wurtzite phase and iron oxide (Fe2O3) has a rhombohedral phase. Fourier Transform Infra-Red spectrum confirms the presence of Zn-O vibration stretching at 428, 480 and 543 cm-1 stretching confirming Fe-O bond formation. Scanning Electron Microscope images exhibited a diverse size and shape of the nanocomposites. The ZnO-90%/Fe2O3-10% and ZnO-10%/Fe2O3-90% nanocomposites reveal good photocatalytic activity with reaction rate constants of 1.5 × 10-2 and 0.66 × 10-2; and 1.3 × 10-2 and 0.60 × 10-2 for methylene blue and methyl red dye respectively. The results revealed that the synthesized ZnO/Fe2O3 nanocomposite is the best catalyst for dye degradation and can be used for industrial applications in future.

Novel preparation of fungal conidiophores biomass as adsorbent for removal of phosphorus from aqueous solution.

The present study focused on phosphorus adsorption by novel fungal conidiophores biomass in aqueous solution. Fungal Conidiophores biomass was prepared from the fungal strains Aspergillus oryzae (YFK) and Fusarium oxysporum (YVS2). The functional groups and morphology of Conidiophores Biomass (CB) from these strains were characterized by FTIR and SEM. FTIR confirms the presence of alcohol, carboxylic acid, carbon dioxide, cyclic alkene, amine, alkene, fluoro compound, and halo compound groups. Batch mode study was carried out with two CB's such as Aspergillus oryzae CB (ACB) and Fusarium oxysporum CB (FCB) with initial concentration of phosphorus ranging from 20 to 100 mg L-1. Based on the batch experiments, the adsorption kinetics (pseudo first order and pseudo second order), isotherms (Freundlich and Langmuir models), and thermodynamic (standard entropy, energy, and enthalpy) parameters were calculated. The adsorption kinetics and isotherm studies showed that the adsorption data well fitted with PSO kinetic model. From the isotherm results, it was found that ACB and FCB exhibited highest adsorption capacity 25.64 mg g-1 and 26.32 mg g-1 of phosphorus respectively at the optimal condition of pH (7), time (90 min), dose (250 mg), and room temperature (35 °C). Thermodynamics values were found to be endothermic and spontaneous in nature for phosphorus adsorption. Finally, the results suggested that the ACB and FCB are economically feasible cost-effective adsorbent for removal of phosphorus in wastewater treatment. Graphical abstract.

Characterization and assessment of two biocontrol bacteria against Pseudomonas syringae wilt in Solanum lycopersicum and its genetic responses.

Pseudomonas and Bacillus species are attractive due to their potential bio-control application against plant bacterial pathogens. Pseudomonas aeruginosa strain D4 and Bacillus stratosphericus strain FW3 were isolated from mine tailings in South Korea. In these potent bacterial strains, we observed improved antagonistic activity against Pseudomonas syringae DC3000. These strains produced biocatalysts for plant growth promotion, and in vivo examination of Solanum lycopersicum included analysis of disease severity, ion leakage, chlorophyll content, and H2O2 detection. In addition, regulation of the defense genes pathogen-related protein 1a (PR1a) and phenylalanine ammonia lyase (PAL) was compared with treated plants and untreated control plants. The results suggest that these two bacterial strains provide protection against plant pathogens via direct and indirect modes of action and could be used as a bio-control agent.

Potential for plant biocontrol activity of isolated Pseudomonas aeruginosa and Bacillus stratosphericus strains against bacterial pathogens acting through both induced plant resistance and direct antagonism.

Phytopathogenic bacteria have caused significant damage to agricultural crops in both controlled and open cultivation practices, imposing heavy losses to farmers. Thereby, the goal of this study was to evaluate Pseudomonas aeruginosa and Bacillus stratosphericus isolated from soil has antagonistic activity against bacterial phytopathogens with the potential to control plant diseases. Isolated novel strains of P. aeruginosa and B. stratosphericus showed broad spectrum of antagonistic activity against five bacterial phytopathogens. Antagonistic activity was examined under optimized pH (8 and 7), carbon sources (lactose and starch), nitrogen sources (ammonium chloride, peptone and ammonium nitrate) for P. aeruginosa and B. stratosphericus, respectively, and biocatalyst production (chitinase, protease and amylase) was studied. Additionally, up-regulation of defense-related genes (PR-1a and PAL) was studied in tomato plants treated with P. aeruginosa and B. stratosphericus. The induction of defense-related genes in tomato plant was triggered after 12 h treatment with a cell concentration of 0.20 O.D. for P. aeruginosa and 0.21 O.D. for B. stratosphericus during treatment period. Broad spectrum antagonistic activity was observed due to antibiotic and siderophore production by P. aeruginosa and B. stratosphericus.

Interaction of cadmium and zinc on accumulation and sub-cellular distribution in leaves of hyperaccumulator Potentilla griffithii.

Potentilla griffithii Hook is a newly found hyperaccumulator plant capable of high tolerance and accumulation of Zn and Cd. We investigated the interactive effects between Cd and Zn on accumulation and vacuolar sequestration in P. griffithii. Stimulatory effect of growth was noted at 0.2 mM Cd and 1.25 and 2.5 mM Zn tested. Accumulation of Zn and Cd in roots, petioles and leaves were increased significantly with addition of these metals individually. However, the Zn supplement decreased root Cd accumulation but increased the concentration of Cd in petioles and leaves. The results from sub-cellular distribution showed that up to 94% and 70% of the total Zn and Cd in the leaves were present in the protoplasts, and more than 90% Cd and Zn in the protoplasts were localized in the vacuoles. Nearly, 88% and 85% of total Cd and Zn were extracted in the cell sap of the leaves suggesting that most of the Cd and Zn in the leaves were available in soluble form. The present results indicate that Zn supplement significantly enhanced the petiole accumulation of Cd and further vacuolar sequestration plays an important role in tolerance, detoxification and hyperaccumulation of these metals in P. griffithii.