Optimal Degradation Conditions Research Articles

Modified Zeolites for the Removal of Emerging Bio-Resistive Pollutants in Water Resources

The increasing presence of pollutants, including pharmaceuticals and pesticides, in water resources necessitates the development of effective remediation technologies. Zeolites are promising agents for pollutant removal due to their high surface area, ion-exchange capacity, natural abundance, and diverse tailorable porous structures. This review focuses on the efficient application of modified zeolites and mesoporous materials as photocatalysts and adsorbents for removing contaminants from water bodies. The adsorption and photodegradation of pesticides and selected non-steroidal anti-inflammatory drugs and antibiotics on various zeolites reveal optimal adsorption and degradation conditions for each pollutant. In most reported studies, higher SiO2/Al2O3 ratio zeolites exhibited improved adsorption, and thus photodegradation activities, due to increased hydrophobicity and lower negative charge. For example, SBA-15 demonstrated high efficiency in removing diclofenac, ibuprofen, and ketoprofen from water in acidic conditions. Metal doped into the zeolite framework was found to be a very active catalyst for the photodegradation of organic pollutants, including pesticides, pharmaceuticals, and industrial wastes. It is shown that the photocatalytic activity depends on the zeolite-type, metal dopant, metal content, zeolite pore structure, and the energy of the irradiation source. Faujasite-type Y zeolites combined with ozone achieved up to 95% micropollutant degradation. Bentonite modified with cellulosic biopolymers effectively removed pesticides such as atrazine and chlorpyrifos, while titanium and/or silver-doped zeolites showed strong catalytic activity in degrading carbamates, highlighting their environmental application potential.

Treatment of high concentration phenol wastewater by low-frequency ultrasonic cavitation and long-term pilot scale study.

Acoustic cavitation is an advanced, eco-friendly oxidation technology effective in removing organic pollutants from water. However, research on its use for degrading phenol, a common and challenging phenolic pollutant, is limited. This study explores the optimal conditions for phenol degradation using acoustic cavitation and assesses its practical application through extensive pilot tests. Results from batch tests show that low-frequency (15kHz) ultrasonic cavitation effectively treats high concentrations of phenol (1000mgL-1). Aeration and acidic pH enhance removal efficiency, while alkaline conditions inhibit degradation. Analysis of total organic carbon (TOC), degradation products, and volatile organic compounds (VOCs) reveals that the primary intermediates are substituted benzenes and alkanes. Long-term pilot tests demonstrated the device's effectiveness in phenol removal and its operational stability over 180 days. The study also establishes a relationship between removal efficiency, hydraulic retention time (HRT), and operating costs, highlighting the feasibility of low-frequency ultrasonic cavitation for treating high-concentration phenolic wastewater and its potential role in the pretreatment stage of biochemical processes.

Unraveling the multiple role of UV in PAA/Fe(III) advanced oxidation: Mechanism, efficiency, and toxicity analysis

In recent years, the advanced Fenton-like oxidation technology based on peracetic acid (PAA) has attracted increasing attention, while accelerating the cycle of Fe(III)/Fe(II) remains a limitation for widespread PAA/Fe(III) system application. Herein, in this study, the dual mechanism of UV synchronous acceleration of Fe(III)/Fe(II) cycling and activation of PAA was systematic investigated with the introduction of UV in PAA/Fe(III) systems. Results suggested that the target pollutant Rhodamine B (RhB) could achieve over 95% degradation within 12minutes in the Fe (III)/PAA/UV system. The crucial roles of UV radiation has been determined to activate PAA independently, and synchronously accelerates the transfer of Fe (III) to Fe (II) to generate hydroxyl radicals (·OH), while also enhancing the generation of Fe (IV), ultimately achieving a redox cycle in Fe (III)/PAA/UV system. The ·OH, Fe(IV) and organic free radicals (R-O·) were identified as the mainly active substances via the various analysis methods including characteristic product detection, quenching experiments, electron paramagnetic resonance (EPR), and fluorescence analysis, and the contribution to the RhB degradation followed as ·OH(68.61%) > Fe(IV) (17.52%) > R-O·(11.69%). 12 intermediates and two potential degradation pathways of RhB were identified by combining density functional theory (DFT) calculations and Ultra-Performance Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry (UPLC-QTOF-MS) analyses, and the ecotoxicity was evaluated through Ecological Structure Activity Relationships (ECOSAR) program. Response surface methodology was employed to analyze optimal degradation conditions, considering Fe(III) and PAA dosage, pH, and inhibitory effects of anions. This study systematically revealed the internal mechanism of Fe(III)/PAA/UV system for organic pollutant degradation and verified its efficiency and eco-friendliness.

Unveiling Optimal Conditions for Phenol Degradation: Response Surface Methodology and ANOVA Analysis of ZnO and Ag-Doped ZnO Photocatalysts

Unveiling Optimal Conditions for Phenol Degradation: Response Surface Methodology and ANOVA Analysis of ZnO and Ag-Doped ZnO Photocatalysts

Optimal nitrite degradation by isolated Bacillus subtilis sp. N4 and applied for intensive aquaculture water quality management with immobilized strains.

The toxicity of nitrite is an issue that cannot be overlooked in nitrogen pollution within aquaculture. A highly efficient bacterium capable of simultaneous nitrification and denitrification was screened from natto, and its 16S rRNA gene sequence was compared to existing records, confirming its identification as Bacillus subtilis sp. N4. The optimal conditions for nitrite degradation by B. subtilis sp. N4 were identified using response surface methodology as 167rpm, pH 6.4, 1g/8mL feed, 0.6 OD600, and 30°C, with a predicted 99 % nitrite removal efficiency. The B. subtilis sp. N4 demonstrated a maximum nitrite concentration tolerance of 60mg/L, with μmax and Ks values calculated using a Monod model analysis of 1.67mg/L/h and 0.29mg/L, respectively. Immobilized B. subtilis sp. N4 could be reused for ten cycles while maintaining a nitrite degradation efficiency of >99 %, and retained a high nitrite-degrading ability after being refrigerated at 4°C for three months. Immobilized B. subtilis sp. N4 effectively reduced ammonia nitrogen, nitrite, and nitrate concentrations in Nile tilapia aquaculture, maintaining them at consistently low levels. Therefore, free or immobilized B. subtilis sp. N4, with both nitrification and denitrification capabilities, has considerable potential for application in the aquaculture industry in the future.

Photodegradation of methylene blue dye on a catalyst mixture (Cu2O and CuO) powder in aqueous medium

In this study, a powder of two stable forms of copper oxide (Cu2O and CuO) was utilized for the photocatalytic degradation of Methylene blue (MB). Various attempts were made to determine the optimal conditions for degradation, including liquid-phase adsorption, initial dye concentration, catalyst weight loading, pH variation, H2O2, and NaI concentration. The results demonstrated that the photocatalytic degradation of MB by the Cu₂O-CuO mixture achieved efficiencies of 87.9% and 97.1%, respectively, in the presence of 0.01 M NaI and 2 mL of H₂O₂. A degradation rate of 97.92% was obtained at pH 12 after 2 hours. However, increasing the amount of dye is significantly reduced the degradation rate value, as the dye molecules blocked the light intensity required for photocatalyst activation. Liquid-phase adsorption studies showed that the adsorption efficiency of MB increased as its initial concentration decreased.Additionally, an acidic medium (pH 2) was found to be optimal for adsorption at 95.69%. The addition of NaI to the reaction medium significantly enhanced the adsorption of MB on the catalyst mixture. In addition, the powder X-ray diffraction (XRD) investigations showed the crystalline system of monoclinic CuO and cubic Cu2O. The morphological analysis using Scanning Electron Microscopy (SEM) revealed irregular shapes of nanostructures. Furthermore, investigations on the catalyst weight effect were investigated.

Degradation dynamics of Trifluralin in Qinghai-Tibet Plateau and screening of its degrading strains.

Trifluralin (FLL) is extensively used in rapeseed fields in the Qinghai-Tibet Plateau (QTP) region. However, the degradation kinetics of FLL in this area and its impact on environmental microbial communities are not yet known. To investigate the degradation patterns and ecological benefits of FLL, this study established a comprehensive method for detecting FLL residues and selected efficient degrading bacterial strains. Degradation experiments were conducted in two typical soil types of the QTP, and the dynamic changes in microbial communities were explored. The results indicated that FLL degradation in soils from two different regions of the QTP followed first-order kinetics, with half-lives of 25 and 39 days, respectively. The application of FLL at 173g/ha significantly increased bacterial richness and diversity in the soils of both regions. Three efficient degrading strains were selected from soil samples: FL-3 (Bacillus velezensis) with a degradation rate of 80.81%, FL-5 (Bacillus velezensis) at 51.18%, and FL-6 (Pseudomonas atacamensis) at 49.98%. Moreover, the optimal degradation conditions for these strains were determined, and it was verified that they had no adverse effects on the germination and seedling growth of rapeseed, wheat, and barley. The findings of this study provide important data for the environmental risk assessment of FLL and suggest potential biological resources for the rational use and environmental remediation of this herbicide. These results are significant for developing safe use and environmental management strategies for FLL in the QTP.

Complete genome sequence of Bacillus pumilus NWMCC0302, a strain for degrading bovine blood

BackgroundDirectly discharging livestock and poultry slaughter blood without proper treatment can cause severe ecological damage. Exploring the use of microorganisms to break down waste blood into smaller molecules such as peptides and amino acids, as well as investigating the possibility of transforming these small molecules into water-soluble fertilizers containing amino acids, holds significant research value in the comprehensive utilization of livestock and poultry blood.ResultsIn this study, a single strain of Bacillus pumilus NWMCC0302, which has effectively degraded bovine blood, was isolated from abattoir blood sludge using casein agar plates and Columbia blood agar plates. The degradation test was carried out using bovine raw blood as a nitrogen source in the medium, and the results showed that the strain degraded 53.83% of bovine blood under optimal degradation conditions. The whole genome sequencing of Bacillus pumilus NWMCC0302 was conducted using the second-generation DNBSEQ platform and the third-generation PacBio platform, employing high-throughput sequencing technology. The size of the strain's entire genome was determined to be 3 868 814 bp with a G-C content of 41.63%. The total gene length accounted for 88.98% of the genome length at 3 442 341 bp and encoded 4 113 genes. The strain contained 79 tRNAs, 24 rRNAs, 7 sRNAs, and 296 repetitive sequences. The gene data obtained from sequencing were also functionally annotated using the COG, KEGG, and VFDB databases. In the COG database, 310 genes were involved in amino acid transport and metabolism, including 10 catabolic proteins related to COGs. In the KEGG database, were 201 genes involved in amino acid metabolism pathways, including 8 genes in nitrogen metabolism pathways and 2 genes in oxidative pathways. The VFDB database contains two lysostaphin genes and one serine protease-hydrolyzed ClpP gene.ConclusionsIn summary, Bacillus pumilus NWMCC0302 was screened for its efficient ability to degrade bovine blood. Additionally, the genetic information of Bacillus pumilus NWMCC0302 was revealed at the genetic level, providing a feasible experimental method for applying this strain to the degradation of blood from slaughtered livestock and poultry. Moreover, it is a potential functional strain for producing amino acid-containing water-soluble fertilisers.

Commercial Blue Textile Dye Decolorization Using Aspergillus oryzae RH1 Isolated From Fermented Miso

AbstractThe improper treatment of effluents from the textile industry is associated with severe health and environmental hazards. This study aimed to isolate and characterize miso‐paste fungi that can decolorize commercial blue textile dyes (identified as Reactive Violet 5 [RV5] through spectral comparison). Response surface methodology (RSM) was employed to determine the optimal decolorization conditions, whereas molecular docking was performed to propose an enzymatic degradation mechanism. One colony, displaying the typical morphological characteristics of Aspergillus oryzae common in miso‐paste starters, exhibited high decolorization potential for RV5. Validation of the RSM analysis using whole fungus A. oryzae RH1 revealed a decolorization performance of 92.33% under the following optimized conditions: 33°C, pH 6.2, dye concentration of 200 ppm, and incubation period of 6 days. The optimal conditions for dye degradation via enzymatic catalysis, with peroxidase as the enzyme, were 51°C and pH 3.0, resulting in a decolorization performance of 48.95% after 60 min of incubation. Molecular docking analysis suggested that the DyP‐type peroxidase produced by A. oryzae RH1 can oxidize the azo bond, which is the chromophore group of RV5. In addition, biosorption was found to play a significant role in the decolorization of A. oryzae RH1. Altogether, these findings lay the basis for the use of A. oryzae RH1 in bioreactor systems for textile wastewater treatment.

Rhombic dodecahedral ZIF-8-supported CuFe2O4 triggers sodium percarbonate activation for enhanced sulfonamide antibiotics degradation: Synergistic roles of heterostructure and photocatalytic mechanisms

Pollution from extensive sulfonamide antibiotic use is a critical research focus, particularly in the remediation of these antibiotics using composite materials. This study employed a CuFe2O4/ZIF-8 composite to activate sodium percarbonate (SPC) for the photo-Fenton-like degradation of the sulfonamide antibiotic sulfamethoxazole (SMX). The optimal conditions for SMX degradation were determined using the CuFe2O4/ZIF-8/SPC/Vis system: a ZIF-8 composite ratio of 40 %, catalyst dosage of 0.15 g/L, SPC concentration of 0.8 mM, and initial pH of 3.0, achieving complete SMX removal within 30 min. After five cycle tests, the leaching rates of copper and iron ions were 0.179 mg/L and 0.376 mg/L, respectively, significantly lower compared to the use of CuFe2O4 alone as the catalyst (Cu: 0.46 mg/L, Fe: 1.43 mg/L). The radicals present in the system were identified, with their contribution rates ranked from highest to lowest as follows: ·OH > h+> ·O2– > CO3·- >1O2. Further mechanistic investigations revealed that the heterogeneous structures in CuFe2O4/ZIF-8 enhanced the efficiency of the photo-Fenton-like reaction by facilitating electron transfer. This study introduced an innovative approach for antibiotic treatment using the CuFe2O4/ZIF-8 composite under visible light irradiation and broadened the technical framework of SPC-based advanced oxidation processes (AOPs) for treating wastewater.

Enhancing photocatalytic degradation of beta-blocker drugs using TiO2 NPs/zeolite and ZnO NPs/zeolite as photocatalysts: optimization and kinetic investigations

This study delves into the development and optimization of photocatalysts, namely ZnO NPs/Zeolite and TiO2 NPs/Zeolite, for the degradation of two beta-blocker drugs, including Atenolol (AT) and Metoprolol (ME). Structural and morphological analyses of the catalysts were conducted, and optimal conditions for drug degradation were determined using a Box-Behnken design. The results underscored the significant influence of pH, catalyst amount, drug concentration, and H2O2 concentration on the degradation process using ZnO NPs/Zeolite and TiO2 NPs/Zeolite as the catalysts. The optimal values of drug concentration, pH, catalyst amount, and H2O2 concentration, were determined to be 32 and 33 mg L−1, 4.2 and 4.6, 428 and 386 mg, and 2.6 and 2.5 mM utilizing ZnO NPs/Zeolite and TiO2 NPs/Zeolite as the catalyst, respectively. Following optimization, the kinetics of the photodegradation process were investigated, revealing promising rates and half-life times for both drugs. The pseudo-first-order rate constants for Atenolol and Metoprolol degradation were 0.064 ± 0.007 min−1 and 0.065 ± 0.004 min−1 with ZnO NPs/Zeolite and 0.071 ± 0.007 min−1 and 0.071 ± 0.006 min−1 with TiO2 NPs/Zeolite, respectively. Furthermore, ZnO NPs/Zeolite and TiO2 NPs/Zeolite demonstrated reusability up to 5 and 6 times, respectively, without significant activity loss. The comparative analysis highlighted the superior performance of TiO2 NPs/Zeolite over ZnO NPs/Zeolite, attributed to lower consumption, shorter degradation time, improved reusability, and compatibility with milder acidic conditions. Overall, the research showcases the potential of ZnO NPs/Zeolite and TiO2 NPs/Zeolite as an effective and sustainable solution for removing Metoprolol and Atenolol contaminants.

La-supported SnO2–CaO composite catalysts for efficient malachite green degradation under UV–vis light

This study presents the development and optimization of La@SnO2–CaO composite catalysts for efficient photocatalytic degradation of malachite green dye in aqueous solutions under UV–vis light irradiation. The catalysts were prepared via conventional incipient-wetness impregnation and thoroughly characterized using advanced analytical techniques, including X-ray diffraction, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy, N2 adsorption–desorption analysis, and scanning electron microscopy. To optimize photodegradation efficiency, the effects of three independent factors were systematically investigated using response surface methodology: Temperature, pH, and Sn/Ca molar ratio. Our results reveal optimal conditions for maximum dye degradation: pH 7, Sn/Ca molar ratio of 0.33, and a process time of 35 min, resulting in a maximum photodegradation efficiency of 98.80% for malachite green dye. Notably, visible light exhibited a more pronounced effect on dye degradation compared to UV light over time, with visible light achieving 25% greater dye removal after 60 min of illumination. Furthermore, the catalyst showed excellent recyclability, retaining 85% of its initial activity after five consecutive cycles. These findings contribute significantly to the development of sustainable methods for dye removal from wastewater and highlight the potential of La@SnO2–CaO composite catalysts in environmental remediation processes, particularly in treating textile industry effluents.

Analysis of an open-air argon plasma driven photo-Fenton reaction for degradation of synthetic dyes: Optical emission spectroscopy and statistical design optimization

This research was designed to treat synthetic dyes in aqueous solutions using an atmospheric pressure argon plasma-driven photo-Fenton process. Optical emission spectroscopy and statistical optimization of the argon plasma-driven photo-Fenton process parameters were performed to efficiently degrade synthetic dyes. Lab-scale experiments were performed utilizing an argon plasma jet coupled with a Fenton reagent mixture of hydrogen peroxide (H2O2) and ferrous ions (Fe2+). Based on the response surface methodology, a statistical Box–Behnken design (BBD) was used to optimize the photo-Fenton process by changing Fe2+ concentration, H2O2 concentration, and plasma treatment time as the control factors. Optical emission spectroscopy was conducted to understand the reactive plasma species in the jet. Boltzmann plot was used to study the plasma temperature. The argon plasma jet contained OH, Ar, N2, and atomic oxygen (O) reactive species and radiations in the visible and ultraviolet range. According to BBD, the maximum dye removal efficiency of 97.01% was possible with 40 mg/l of Fe2+ ions, 200 mg/l of H2O2, and 17.5 min of plasma exposure. The statistical model is well-fitted to a second-order polynomial equation. The optimum conditions for dye degradation were Fe2+ (40 g/l), H2O2 (200 g/l), and a plasma treatment time 23.18 min obtained from the optimizer plot. The statistical model showed a 99.76% fit to the experimental data of dye degradation.

Magnetic MgFeO@BC Derived from Rice Husk as Peroxymonosulfate Activator for Sulfamethoxazole Degradation: Performance and Reaction Mechanism.

Heterogeneous Mg-Fe oxide/biochar (MgFeO@BC) nanocomposites were synthesized by a co-precipitation method and used as biochar-based catalysts to activate peroxymonosulfate (PMS) for sulfamethoxazole (SMX) removal. The optimal conditions for SMX degradation were examined as follows: pH 7.0, MgFeO@BC of 0.4 g/L, PMS concentration of 0.6 mM and SMX concentration of 10.0 mg/L at 25 ℃. In the MgFeO@BC/PMS system, the removal efficiency of SMX was 99.0% in water within 40 min under optimal conditions. In the MgFeO@BC/PMS system, the removal efficiencies of tetracycline (TC), cephalexin (CEX), ciprofloxacin (CIP), 4-chloro-3-methyl phenol (CMP) and SMX within 40 min are 95.3%, 98.4%, 98.2%, 97.5% and 99.0%, respectively. The radical quenching experiments and electron spin resonance (ESR) analysis suggested that both non-radical pathway and radical pathway advanced SMX degradation. SMX was oxidized by sulfate radicals (SO4•-), hydroxyl radicals (•OH) and singlet oxygen (1O2), and SO4•- acted as the main active species. MgFeO@BC exhibits a higher current density, and therefore, a higher electron migration rate and redox capacity. Due to the large number of available binding sites on the surface of MgFeO@BC and the low amount of ion leaching during the catalytic reaction, the system has good anti-interference ability and stability. Finally, the intermediates of SMX were detected.

Plasma coupled with ultrasonic for degradation of organic pollutants in water: Revealing the generation of free radicals and the dominant degradation pathways

This study explores the synergistic effects of dielectric barrier discharge (DBD) plasma coupled with ultrasound (US) in the degradation of organic pollutants in water. The optimal degradation conditions were determined to be 100 W ultrasonic power, 190 V DBD plasma voltage, and neutral pH. The combination of DBD plasma and US significantly enhances the generation of reactive species (·OH, ·O2-, and 1O2), leading to a 97.3 % degradation efficiency of methyl orange (MO), which is 17.3 % higher than DBD plasma alone. Electron spin resonance (ESR) identified ·OH, ·O2-, and 1O2 in DBD/US system, and radical scavengers were employed to elucidate their roles. The degradation process was assessed through changes in pH, conductivity, TOC and COD, with characterization and analysis via UV-Vis and LC-MS. By combining LC-MS with density functional theory (DFT) calculations, nine intermediates were identified and three degradation pathways dominated by free radicals were established. Additionally, the DBD/US system treated wastewater containing sulfamethoxazole (SMX), sulfadiazine (SDZ), tetracycline (TC), and ciprofloxacin (CIP), achieving degradation rates exceeding 80 %. These findings suggest that the DBD/US coupled system holds promising potential for treating organic pollutant wastewater.

Isolation and degradation characterization of a 1, 4-dioxane-degrading bacterial strain

To address the potential pollution caused by the carcinogen 1, 4-dioxane in aquatic environments, we isolated a highly efficient 1, 4-dioxane-degrading bacterial strain, designated as DXTK-010, from the groundwater contaminated by 1, 4-dioxane. According to the morphological characteristics, the phylogenetic tree established based on the 16S rRNA gene sequence, and the whole genome sequence, we identified DXTK-010 as Aminobacter aminovorans. This strain demonstrated robust degradation capacity within a temperature range of 20 ℃ to 37 ℃ and a pH range of 5.0 to 8.0. Furthermore, single-factor experiments indicated the optimal degradation conditions at 30 ℃ and pH 7.5. Under the optimal conditions, the strain completely degraded 200 mg/L of 1, 4-dioxane within 24 h, achieving a maximum degradation rate of 9.367 mg/(L·h). The Monod equation was adopted to fit the degradation kinetics of 1, 4-dioxane at different initial concentrations, which revealed a maximum specific degradation rate of 0.224 mg 1, 4-dioxane/(mg protein·h), a half-saturation constant (Ks) of 41.350 mg/L, and a cell yield of 0.130 mg protein/(mg 1, 4-dioxane). Whole genome sequencing revealed a circular chromosome and three plasmids within DXTK-010. Functional gene annotation and analysis underscored the significance of the propane monooxygenase gene cluster and alcohol dehydrogenase gene in facilitating the efficient degradation of 1, 4-dioxane by this strain. DXTK-010 outperformed the existing degraders for 1, 4-dioxane, expanding the strain resources for the bioremediation of 1, 4-dioxane pollution. This study provides a theoretical basis for the practical application of DXTK-010 in the remediation of 1, 4-dioxane pollution.

Harnessing multifunctional antimony doped Tin (IV) sulfide nanosheets for chlorpyrifos degradation and hydrogen evolution

Multifunctional photocatalysts are vital for advancing environmental sustainability and clean energy. The hydrothermal method helped in optimized antimony (Sb) doping in the Tin (IV) sulfide (SnS2) lattice, increasing surface area with nanosheet assortment, as confirmed by Scanning Electron Microscopy and BET (Brunauer, Emmett and Teller) analysis. Moreover, the Fermi level shift towards conduction band within the semiconductor, increasing free electron concentration which enhanced conductivity and altered electronic properties. Photocatalysts were evaluated for Chlorpyrifos pesticide degradation, with studies conducted on photocatalytic parameters such as catalyst dosage, pesticide concentration, and pH to ascertain optimal degradation conditions. The 6 wt% Sb-doped SnS2 (6Sb:SnS2) demonstrated highest degradation efficiency within 60 min and degradation obeyed a pseudo first-order kinetic model with a rate constant of 0.0349 min−1. The degradation pathway of Chlorpyrifos and its transformation products was elucidated through High-Performance Liquid Chromatography-tandem mass spectroscopy. In addition, Sb doping empowers the surface traps and hydrophilicity of photocatalysts towards successful interaction between photogenerated electrons/holes with adsorbed oxidizable/reducible species. Moreover, 6Sb:SnS2 exhibited superior hydrogen evolution of 214.39 µmolg−1h−1, along with improved stability. Significantly, 6Sb:SnS2 attained Apparent Quantum Yield (AQY400 nm) of 39.49 % attributed to the doping induced band structure modification of SnS2 to match the hydrogen ion reduction potential.

Identification and characterization of Morganella morganii strain YC12-C3 and Enterococcus faecalis strain YC12-C10 and elucidation of its deoxynivalenol-degrading potential.

Deoxynivalenol ( DON) is one of the most harmful mycotoxins in food or feed or Traditional Chinese Medicine. An efficient and applicable method for the detoxification of DON is urgently developed. 1152 strains were isolated from the intestinal contents of crucian. Morganella morganii YC12-C3 and Enterococcus faecalis YC12-C10 were screened with the highest degradation rate of DON via HPLC methods. The optimal degradation condition of YC12-C3 and YC12-C10 is co-cultured 24 h and 36 h at 28 ℃ in LB medium with pH 7 and 1.0% inoculation dosage, respectively. LC-MS/MS and 1H NMR results show that YC12-C10 and YC12-C3 can transform DON to 3-deoxy-6-demethanol-DON, a new metabolite biotransformed from DON, by deoxidization at C3 hydroxy and de-methanal reaction at methanol moiety of C6. In addition, the DON-degradation in agricultural material assay showed that YC12-C10 and YC12-C3 can degrade 150 μg·kg-1 DON in Coix lacryma-jobi, with a degradation rate of 68.89% and 59.94%, respectively. This result shows that YC12-C10 and YC12-C3 have a sound efficiency in removing DON ability in Coix lacryma-jobi, providing a new strain resource and application technique for biological detoxification of DON in food or feed or TCM industry.

Unveiling six novel bacterial strains for fipronil and thiobencarb biodegradation: efficacy, metabolic pathways, and bioaugmentation potential in paddy soil.

Soil bacteria offer a promising approach to bioremediate pesticide contamination in agricultural ecosystems. This study investigated the potential of bacteria isolated from rice paddy soil for bioremediating fipronil and thiobencarb, common agricultural pesticides. Bacterial isolates capable of degrading fipronil and thiobencarb were enriched in a mineral salt medium. A response surface methodology with a Box-Behnken design was utilized to optimize pesticide degradation with the isolated bacteria. Bioaugmentation tests were performed in paddy soils with varying conditions. Six strains, including single isolates and their mixture, efficiently degraded these pesticides at high concentrations (up to 800 µg/mL). Enterobacter sp., Brucella sp. (alone and combined), and a mixture of Stenotrophomonas sp., Bordetella sp., and Citrobacter sp. effectively degraded fipronil and thiobencarb, respectively. Notably, a single Pseudomonas sp. strain degraded a mixture of both pesticides. Optimal degradation conditions were identified as a slightly acidic pH (6-7), moderate pesticide concentrations (20-50 µg/mL), and a specific inoculum size. Bioaugmentation assays in real-world paddy soils (sterile/non-sterile, varying moisture) demonstrated that these bacteria significantly increased degradation rates (up to 14.15-fold for fipronil and 5.13-fold for thiobencarb). The study identifies these novel bacterial strains as promising tools for bioremediation and bioaugmentation strategies to tackle fipronil and thiobencarb contamination in paddy ecosystems.

Biodegradation of dimethachlon by Arthrobacter sp. K5: Mechanistic insights and ecological implications

Dimethachlon, an agricultural fungicide, poses a potential risk to both the ecosystem and human health. Microbial degradation provides a safe, efficient, and environmentally friendly method for eliminating pesticide residues from the environment. In this study, a dimethachlon-degrading bacterium, Arthrobacter sp. K5, was isolated and characterized by the enrichment technique. Strain K5 was observed to initially convert dimethachlon into 4-(3,5-dichloroanilino)-4-oxobutanoic acid, which was subsequently transformed into 3,5-dichloroaniline and succinic acid. Strain K5 effectively utilized dimethachlon as the sole carbon source, converting 100 mg L−1 dimethachlon to 3,5-dichloroaniline within 36 h at 30°C. The optimum degradation conditions were pH 7.0, a temperature of 30°C, and a NaCl concentration range of 0–0.1 % (w/v). In addition, 1 mM Cd2+, Cu2+, and Zn2+ could considerably decrease the dimethachlon degradation activity. Enzyme activity analysis revealed that strain K5 contains intracellular enzymes that can metabolize dimethachlon into 3,5-dichloroaniline. The strain K5 genome was sequenced, and four putative dimethachlon-degrading enzymes were hypothesized in strain K5. In addition, the genus Arthrobacter is extensively dispersed in metagenomes from various soil environments. This study enhances our understanding of the role of the genus Arthrobacter in dimethachlon degradation.