Transition metal doped CeO2 for photocatalytic removal of 2-chlorophenol in the exposure of indoor white light and antifungal activity

Besides natural sunlight and expensive artificial lights, economical indoor white light can play a significant role in activating a catalyst for photocatalytic removal of organic toxins from contaminated water. In the current effort, CeO2 has been modified with Ni, Cu, and Fe through doping methodology to study the removal of 2-chlorophenol (2-CP) in the illumination of 70 W indoor LED white light. The absence of additional diffractions due to the dopants and few changes such as reduction in peaks’ height, minor peak shift at 2θ (28.525°) and peaks’ broadening in XRD patterns of modified CeO2 verifies the successful doping of CeO2. The solid-state absorption spectra revealed higher absorbance of Cu-doped CeO2 whereas a lower absorption response was observed for Ni-doped CeO2. An interesting observation regarding the lowering of indirect bandgap energy of Fe-doped CeO2 (∼2.7 eV) and an increase in Ni-doped CeO2 (∼3.0 eV) in comparison to pristine CeO2 (∼2.9 eV) was noticed. The process of e-– h+ recombination in the synthesized photocatalysts was also investigated through photoluminescence spectroscopy. The photocatalytic studies revealed the greater photocatalytic activity of Fe-doped CeO2 with a higher rate (∼3.9 × 10−3 min-1) among all other materials. Moreover, kinetic studies also revealed the validation of the Langmuir-Hinshelwood kinetic model (R2 = 0.9839) while removing 2-CP in the exposure of indoor light with a Fe-doped CeO2 photocatalyst. The XPS analysis revealed the existence of Fe3+, Cu2+ and Ni2+ core levels in doped CeO2. Using the agar well-diffusion method, the antifungal activity was assessed against the fungus M. fructicola and F. oxysporum. Compared to CeO2, Ni-doped CeO2, and Cu-doped CeO2 nanoparticles, the Fe-doped CeO2 nanoparticles have outstanding antifungal properties

Highly Efficient and Sustainable Spent Mushroom Waste Adsorbent Based on Surfactant Modification for the Removal of Toxic Dyes

The treatment of wastewater always demands eco-friendly and cost-efficient adsorbents. In this paper, spent mushroom waste (SMW) was modified by a cationic surfactant (cetyltrimethylammonium bromide, CTAB) to eliminate toxic dyes. A characterization of adsorbents confirmed that CTAB was successfully embedded into the SMW structure. The spent mushroom waste, modified by CTAB (SMWC), exhibited an excellent adsorption capacity of 249.57 mg·g−1, 338.67 mg·g−1, and 265.01 mg·g−1 for the Direct red 5B (DR5B), Direct blue 71 (DB71), and Reactive black (RB5) dyes, respectively. Batch experiments indicated that the dye adsorption of SMWC depended mainly on pH, dye concentration, temperature, and ionic strength. The adsorption isotherm could be fitted to the Langmuir model and described by the pseudo-second-order kinetic model. The dye adsorption mechanism was dominated mostly by the chemosorption of the dyes and the SMWC surface. Thermodynamic parameters showed that the adsorption was endothermic and spontaneous. SMWC could successfully remove over 90% of dyes from various water samples. This can be considered a feasible waste resource utility, since it meets both the ecological and the economic requirements for auspicious industrial applications

A novel and efficient fungal delignification strategy based on versatile peroxidase for lignocellulose bioconversion

Abstract Background The selective lignin-degrading white-rot fungi are regarded to be the best lignin degraders and have been widely used for reducing the saccharification recalcitrance of lignocellulose. However, the biological delignification and conversion of lignocellulose in biorefinery is still limited. It is necessary to develop novel and more efficient bio-delignification systems. Results Physisporinus vitreus relies on a new versatile peroxidase (VP)-based delignification strategy to remove enzymatic recalcitrance of corn stover efficiently, so that saccharification of corn stover was significantly enhanced to 349.1 mg/g biomass (yield of glucose) and 91.5% (hydrolysis yield of cellulose) at 28 days, as high as levels reached by thermochemical treatment. Analysis of the lignin structure using pyrolysis–gas chromatography–mass spectrometry (Py–GC/MS) showed that the total abundance of lignin-derived compounds decreased by 54.0% and revealed a notable demethylation during lignin degradation by P. vitreus. Monomeric and dimeric lignin model compounds were used to confirm the ligninolytic capabilities of extracellular ligninases secreted by P. vitreus. The laccase (Lac) from P. vitreus could not oxidize nonphenolic lignin compounds and polymerized β-O-4 and 5-5′ dimers to precipitate which had a negative effect on the enzymatic hydrolysis of corn stover in vitro. However, the VP from P. vitreus could oxidize both phenolic and nonphenolic lignin model compounds as well as break the β-O-4 and 5-5′ dimers into monomeric compounds, which were measured by high-performance liquid chromatography–electrospray ionization–mass spectrometry (LC–ESI–MS). Moreover, we showed that addition of purified VP in vitro improved the enzymatic hydrolysis of corn stover by 14.1%. Conclusions From the highly efficient system of enzymatic recalcitrance removal by new white-rot fungus, we identified a new delignification strategy based on VP which could oxidize both phenolic and nonphenolic lignin units and break different linkages in lignin. In addition, this is the first evidence that VP could break 5-5′ linkage efficiently in vitro. Moreover, VP improved the enzymatic hydrolysis of corn stover in vitro. The remarkable lignin-degradative potential makes VP attractive for biotechnological applications

Principles of microbial degradation of petroleum hydrocarbons in the environment

Petroleum hydrocarbons (PHs) are a big group of chemicals that have caused a major concern because of their widespread distribution into the environment, bioaccumulation potential, harmful effects and biodegradation resistance. Soil and water pollution is mainly attributed to hydrocarbons from oil refineries, petrochemical industries, human activities and other sources. The mechanisms and factors that affect biodegradation should be further understood because the choice of bioremediation technique depends on them. This review described fungal PHs degradation, emphasized the relevant physicochemical and biological factors, and discussed the enzymatic systems influencing PHs biodegradation. Keywords: Biotic and abiotic factors, Biodegradation, Bioremediation, Enzymes, Petroleum hydrocarbon

MOESM4 of A novel and efficient fungal delignification strategy based on versatile peroxidase for lignocellulose bioconversion

Additional file 4. Cyclic voltammograms of Lac and VP

Nanotheranostic fabrication of iron oxide for rapid photocatalytic degradation of organic dyes and antifungal potential

This research work includes the fabrication of iron oxide nanoparticles (Fe2O3 NPs) by green construction approach using Wisteria sinensis leaves extract. Due to its eco-friendly approach, the synthesis of iron oxide NPs (Fe2O3 NPs) using various plant sources, such as plant parts, and microbial cells have gained a lot of attention in recent years. Cost-effectiveness and ease of availability make Wisteria sinensis leaves extract a potential candidate for the construction of iron oxide NPs. The various key features like biocompatibility, non-toxicity capping, and stabilizing agents present in biological sources are advantageous for usage in a variety of applications. The phytoconstituents present in the leaf extract of Wisteria sinensis serve as reducing and stabilizing agents. The biologically fabricated (Fe2O3 NPs) were analyzed using FT-IR, XRD, UV–vis spectroscopy, and SEM. In the present work, the antioxidant and photocatalytic dye degradation efficiency of Fe2O3 NPs has been studied. The dye degradation efficiency of methylene blue dye was found to be 87% at 180 min upon exposure to sunlight. The capacity of Fe2O3 NPs to scavenge 2,2-diphenyl-1-picrylhydrazyl hydrate free radicals (DPPH) was examined using a UV–Vis spectrophotometer. The study compared the radical scavenging activity (RSA) of Fe2O3 nanoparticles (NPs) with that of the standard antioxidant ascorbic acid. The results demonstrated that Fe2O3 NPs have a greater ability to scavenge radicals than ascorbic acid. The half-maximal inhibitory concentration (IC50) of Fe2O3 NPs was observed to range from 0.12 to 0.17. Furthermore, Fe2O3 NPs displayed the highest antifungal activity, with an inhibition zone of 26.8 mm against F. oxysporum. These findings suggest that the biologically synthesized Fe2O3 NPs possess potent antimicrobial and dye degradation properties

Biosynthesis of Silver Nanoparticles Using Kitchen Vegetable Waste Extract for Application against Poultry Pathogens, Antimicrobial Activity, and Photocatalytic Dye Degradation

Bacteria develop resistance against antimicrobial drugs, and new remediations are constantly being introduced in the market. Silver and its compounds have strong resistance against different bacteria. The vegetable waste extract-synthesized silver nanoparticles (VWE-AgNPs) have distinct properties and potential applications because of their unique size and morphology. The fundamental purpose of this study was to develop an environment-friendly method for the synthesis of VWE-AgNPs to avoid the use of hazardous chemicals that cause danger to the environment as well as recycling vegetable waste material. The VWE-AgNPs were synthesized by mixing 1 mM AgNO3 solution and VWE at room temperature. The VWE-AgNPs were characterized by UV-visible spectroscopy, FTIR, SEM, and EDX. The synthesized particles showed good antibacterial properties against poultry bacteria Salmonella gallinarum and Salmonella enteritidis (growth reduction of 31 mm and 18 mm at 80 mg/mL AgNPs, respectively). The results demonstrated that VWE-AgNPs inhibited the growth of tested bacterial strains. The fabricated VWE-AgNPs also had the potential to act as a green photocatalyst for degradation of 87.7% of methylene blue (MB) and 90.76% of methyl orange (MO) nearly at 3.25 h and 1 h sunlight exposure time, respectively. The highest antifungal activity, which was determined to be 36.5 mm and 31.8 mm against Alternata sp. and C. albican, was discovered to be in VWE-AgNPs

Photocatalytic Reduction of Cr(VI) to Cr(III) and Photocatalytic Degradation of Methylene Blue and Antifungal Activity of Ag/TiO2 Composites Synthesized via the Template Induced Route

Water treatment through photocatalysts has become an important topic regarding environmental protection. In the present study, silver and TiO2 (Ag/TiO2) composites for photocatalysts were effectively synthesized by adopting the template induced method. The prepared samples were characterized using XRD, FTIR spectroscopy, SEM, and EDX. The constructed samples’ particle size and shape were evaluated using a SEM, and the XRD patterns showed anatase crystalline phases. Their morphologies were controllable with changing concentration of reactants and calcination temperature. The synthesized composites act as catalyst in the degradation of methylene blue (MB) and reduction of Cr(VI) to Cr(III) under solar irradiation. In both of these activities, the best result has been shown by the 0.01 Ag/TiO2 composite. Methanol is used as the hole scavenger in the reduction of Cr(VI) to Cr(III). While the pH factor is important in the photocatalytic reduction of Cr(VI) to Cr(III). According to observations, S. macrospora and S. maydis were each subject to 0.01 Ag/TiO2 nanocomposites maximum antifungal activity, which was 38.4 mm and 34.3 mm, respectively. The outcomes demonstrate that both photocatalytic and antifungal properties are effectively displayed by the constructed material

Isotherm and kinetic studies for the adsorption of methylene blue onto a novel Mn3O4-Bi2O3 composite and their antifungal performance

Metal oxide-based adsorbents are quite in for wastewater treatment because of their selectivity, stable structure and very low solubility in aqueous systems. To explore the adsorption of methylene blue (MB), Mn3O4-Bi2O3 adsorbents were made using a wet-impregnation technique with various concentrations of Mn3O4. The presence of Mn3O4 contents on the surface of monoclinic Bi2O3 was confirmed through representative scanning electron micrographs. The diffractions pertaining to cubic Mn3O4 and monoclinic Bi2O3 were noticed in the XRD pattern of 5% Mn3O4-Bi2O3 which confirm the composite nature of the adsorbent. XPS analysis revealed the existance of Bi 4f, Bi 4d, Bi 4p, Bi4s, and Mn 2p core levels in Mn3O4-Bi2O3. The adsorption study divulged highest efficiency (∼95% and qe = ∼1.4 mgg-1) of 5% Mn3O4-Bi2O3 composite among other contestants in removing 30 ppm MB at 28 (Formula presented.) C, pH 7 and 250 rpm. In addition to the determination of adsorption ability, the effect of preliminary dye concentration (5, 10, 20, and 30 ppm) and contact time (0.5–6 h) on the removal efficiency of prepared adsorbents were also monitored. The adsorption data from the batch experiments were evaluated using the Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich-Kaganer (DRK) adsorption isotherms and pseudo 1st and 2nd-order kinetic models. The fitting of adsorption isotherms and kinetic models revealed the formation of adsorbate’s monolayer on the surface of adsorbents through the process of chemisorption. Through FTIR measurement, the MB adsorption onto the effective adsorbent (5% Mn3O4-Bi2O3) was also confirmed. Moreover, TGA analysis showed ∼1.5% weight loss by 5% Mn3O4-Bi2O3 before MB adsorption whereas ∼2.6% weight loss was noticed after dye adsorption onto the adsorbent. The antifungal activity was evaluated against the fungi A. solani and M. fructicola using the agar well diffusion technique. The 5% Mn3O4-Bi2O3 composites have exceptional antifungal characteristics compared to Bi2O3 and Mn3O4, with zone inhibition values of 58.6 and 53.9 mm, respectively

Fabrication of novel oxochalcogens halides of manganese and tin nanocomposites as highly efficient photocatalysts for dye degradation and excellent antimicrobial activity

The dark brown and white crystals of manganese and tin (Mn2Se3Cl2O7 and SnSe3O4Cl) have been synthesized by solid-state reaction at 450 C. The morphology and the elemental analysis of newly synthesized compounds were studied by SEM and EDX Analysis. SEM analysis reveals that the particle size for Mn2Se3Cl2O7 was found to be 0.2–2.5 μm and for SnSe3O4Cl 2.0–6.0 μm. The EDX studies showed the presence of Mn, Se, O, Cl, and Sn elements. Powdered XRD confirmed the presence of a new phase present in these compounds. Under UV-vis irradiation, the kinetics of methylene blue (MB) degradation catalyzed by produced nanoparticles were monitored. The dye degradation efficiency was estimated, and results reveals that after 150 min of irradiation, almost 75% of the dye was degraded in the presence of Mn compound while 71% degradation was shown by Sn compound. Both composites display antimicrobial activity against Staphylococcus aureus and Escherichia coli with a maximum value of 34.5 mm. The maximum antimicrobial activity shown by Mn-incorporated nanocomposites estimated at 32.5 mm was against Gram-positive bacteria and 26.4 mm against Gram-negative bacteria. Similarly, the maximum antifungal activity shown by Sn incorporated estimated at 33.9 mm was compared to Gram-positive bacteria and 27.8 mm against Gram-negative bacteria