Degradation Of Carbendazim Research Articles

Carbendazim imprinted electrochemical sensor based on CdMoO4/g-C3N4 nanocomposite: Application to fruit juice samples.

Carbendazim (CAR) as a fungicide is utilized for fruits and vegetables to provide diseases' control and the degradation of carbendazim having benzimidazole ring is slow. Herein, a molecularly imprinted electrochemical sensor based on CdMoO4/g-C3N4 nanocomposite was prepared for CAR determination in fruit juice samples. Firstly, CdMoO4/g-C3N4 nanocomposite with high yield was fabricated via one-pot in-situ hydrothermal approach including environmentally friendly method. Formation of CAR imprinted polymers was performed on CdMoO4/g-C3N4 nanocomposite modified glassy carbon electrode (GCE) in presence of CAR as template and pyrrole (Py) as a monomer by cyclic voltammetry (CV) technique. Following the morphological, structural, and optical characterization of as-synthesized nanocomposite, the electrochemical techniques were also implemented to evaluate the electrochemical features of fabricated electrodes. The limit of quantification (LOQ) and limit of detection (LOD) values were calculated as 0.1×10-10M, and 2.5×10-12M, respectively in addition to satisfactory selectivity, stability, reproducibility and reusability. The findings revealed that the proposed CAR imprinted electrochemical sensor can be successfully employed in food safety.

Degradation of carbendazim in aqueous solution by different settings of photochemical and electrochemical oxidation processes

The present study analyzed the performance of photochemical and electrochemical techniques in the degradation and mineralization of the pesticide carbendazim (CBZ). Direct photolysis (DP), heterogeneous photocatalysis (HP), photoelectrocatalysis (PEC), and electrochemical oxidation (EO) were tested, and the influence of UV radiation, current density (j), and supporting electrolyte concentration were evaluated. The results suggest that CBZ is only degraded by DP when UV-C254nm is used. For HP, the CBZ degradation was observed both when UV-A365nm or UV-C254nm were used, which is related to the reactive oxygen species (ROS) formed by the photocatalytic activity (photon-ROS). Neither DP nor HP were able to mineralize CBZ, demonstrating its resistance to photomediated processes. For EO, regardless of the j, there were higher CBZ degradation and mineralization than those observed when using DP and HP. The increase in the supporting electrolyte concentration (Na2SO4) did not affect the levels of degradation and mineralization of CBZ. Concerning the PEC, a CBZ mineralization of 52.2% was accomplished. These findings demonstrate that the EO is the main pathway for CBZ mineralization, suggesting an additional effect of the electro-ROS on the photon-ROS and UV-C254nm. The values of mineralization, kinetics, and half-life show that PEC UV-C254nm with a j of 15 mA cm−2 was the best setting for the degradation and mineralization of CBZ. However, when the values of specific energy consumption were considered for industrial applications, the use of EO with a j of 3 mA cm−2 and 4 g L−1 of Na2SO2 becomes more attractive. The assessment of by-products formed after this best cost-efficient treatment setting revealed the presence of aromatic and aliphatic compounds from CBZ degradation. Acute phytotoxicity results showed that the presence of sodium sulfate can be a representative factor regarding the toxicity of samples treated in electrochemical systems.

Degradation of Carbendazim by Molecular Hydrogen on Leaf Models.

Although molecular hydrogen can alleviate herbicide paraquat and Fusarium mycotoxins toxicity in plants and animals, whether or how molecular hydrogen influences pesticide residues in plants is not clear. Here, pot experiments in greenhouse revealed that degradation of carbendazim (a benzimidazole pesticide) in leaves could be positively stimulated by molecular hydrogen, either exogenously applied or with genetic manipulation. Pharmacological and genetic increased hydrogen gas could increase glutathione metabolism and thereafter carbendazim degradation, both of which were abolished by the removal of endogenous glutathione with its synthetic inhibitor, in both tomato and in transgenic Arabidopsis when overexpressing the hydrogenase 1 gene from Chlamydomonas reinhardtii. Importantly, the antifungal effect of carbendazim in tomato plants was not obviously altered regardless of molecular hydrogen addition. The contribution of glutathione-related detoxification mechanism achieved by molecular hydrogen was confirmed. Our results might not only illustrate a previously undescribed function of molecular hydrogen in plants, but also provide an environmental-friendly approach for the effective elimination or reduction of pesticides residues in crops when grown in pesticides-overused environmental conditions.

Gadolinium sesquisulfide anchored N-doped reduced graphene oxide for sensitive detection and degradation of carbendazim

Agriculture is having a major role in solving issues associated with food shortages across the globe. Carbendazim (CZM) is one of the fungicides which is commonly used in agriculture to grow crops in large quantities and fast. Monitoring CZM content is in high demand for environmental remediation. The present work deals with the synthesis of gadolinium sesquisulfide anchored Nitrogen-doped reduced graphene oxide (Gd2S3/NRGO) through a simple microwave-assisted method. X-ray diffraction and morphological studies confirm the formation of the nanocomposite. Gd2S3/NRGO showed enhanced activity both in electrochemical detection and light-driven degradation of CZM compared to Gd2S3 and NRGO. Gd2S3/NRGO modified glassy carbon electrode (GCE) exhibit a wide linear range of 0.01–450 μM CZM with 0.009 μM LOD using differential pulse voltammetry (DPV). Gd2S3/NRGO@GCE showed good selectivity, stability, and recovery (98.13–99.10%) in the river water sample. In addition, Gd2S3/NRGO has been explored towards the visible-light-induced degradation of CZM. The reactions conditions were optimized to achieve maximum efficiency. 94% of CZM was degraded within 90 min in presence of Gd2S3/NRGO. Mechanism of electrochemical redox reaction and degradation of CZM in presence of Gd2S3/NRGO has been explored to the maximum extent possible. Degradation intermediates were identified using LC-MS.

Role of Plasmid in Pesticide Degradation and Metal Tolerance in Two Plant Growth-Promoting Rhizobacteria Bacillus cereus (NCIM 5557) and Bacillus safensis (NCIM 5558).

Disha A (Bacillus cereus) and Disha B (Bacillus safensis) were isolated from pesticide-infested agricultural field and showed tolerance against pesticides, heavy metals, and antibiotics. The isolates exhibited PGPR activities in vitro as well as in field conditions in lentil (Lens culinaris) and cow pea (Vigna unguiculata). Both the Bacillus species could not be grown in mineral salt medium but efficiently grown in the media supplemented with pesticide (imidacloprid/carbendazim) demonstrating the utilization of pesticide as carbon/nitrogen source. The HPLC studies exhibited the pesticide (imidacloprid/carbendazim) degradation by both the bacteria. B. safensis showed better degradation of carbendazim (88.93%) and imidacloprid (82.48%) than that of B. cereus 78.07% and 49.12%, respectively. The bacterial isolates showed high concentration of heavy metal tolerance viz. lead, molybdenum, cadmium, copper, cobalt, and zinc, except mercury. Both the bacteria possessed single plasmid. The plasmid-cured isolates of B. cereus did not tolerate any pesticide, whereas that of B. safensis tolerated all the pesticides, like wild strains. The plasmid curing experiments did not affect the heavy metal tolerance ability of both the bacteria indicating the genomic nature of heavy metal tolerance genes, whereas pesticide resistance genes are plasmid-dependent in B. cereus but genomic in B. safensis.

Chemical kinetic modeling of organic pollutant degradation in Fenton and solar photo-Fenton processes

The oxidation of organic pollutants by Fenton's reagent is commonly considered as a single-stage process that conforms to pseudo first-order kinetics. However, pollutant oxidation would exhibit a two-stage pattern when the initial dosage of Fenton's reagent is sufficiently high. This study investigated the fast oxidation kinetics of a model pollutant, malachite green (MG), in Fenton process in real time using continuous on-line spectrophotometric detection. A chemical kinetic model was further developed, which could well predict the effect of initial concentrations of Fe2+, H2O2, and MG on the degradation of MG in Fenton and solar photo-Fenton processes. The model could also be adapted to model the kinetics of MG mineralization. Modeling results reveal that the significant enhancement in the degradation rate of MG in the second stage of Fenton process by sunlight irradiation was contributed mainly by the production of hydroxyl radicals from H2O2 photolysis. The chemical kinetic model also performed well in describing the degradation and mineralization kinetics of carbendazim and thiabendazole in solar photo-Fenton process. The improved understanding on the fast kinetics of pollutant degradation and the chemical kinetic model developed could help optimize the treatment conditions for organic pollutants in Fenton and solar photo-Fenton processes.

Potential effects of Rhodococcus qingshengii strain djl-6 on the bioremediation of carbendazim-contaminated soil and the assembly of its microbiome

As a widely used fungicide, the environmental fate of carbendazim and its residues in agricultural products have caused great concern. However, its effects on soil microbial communities are largely unknown. Herein, we used high-throughput sequencing to reveal the effects of high and low dose of carbendazim and its degrading strain, Rhodococcus qingshengii strain djl-6, on the composition, diversity, and interrelationship of soil bacterial and fungal communities in short- and medium-term under laboratory conditions. The results showed that carbendazim exhibited an increased negative impact on bacterial communities and reduced the proportion of dominant fungal phylum Ascomycota during a 14-day incubation period. Only the impacts of low-dose carbendazim (2 mg·kg−1 dry soil) on fungal community were weakened. Network analysis showed that carbendazim increased the connectivity and modularity of microbial co-occurrence networks. Strain djl-6 exhibited good potential for bioremediation of carbendazim-contaminated soils. Moreover, it driven the assembly of potential carbendazim-degrading consortia from indigenous microbial communities; and members of the genera Arthrobacter, Bacillus, Brevundimonas, Lysinibacillus, Massilia, Mycobacterium, Paenibacillus, and Pseudarthrobacter might be participated in the degradation of carbendazim. Taken together, our study provides a relatively comprehensive understanding of the effects of carbendazim and its degrading strain djl-6 on soil microbial communities.

Electrochemical Detection and Degradation of Carbendazim at Poly (Vat Violet 2r) Modified GCE

To increase the electrochemical activity of the working electrode, vat violet 2R dye was electro-polymerized on the GCE surface i.e., poly (VVR)/GCE. Utilizing various voltammetric techniques including such cyclic voltammetric (CV), differential pulse voltammetric (DPV), and square wave voltammetric (SWV) technique, the fabricated glassy carbon electrode demonstrated excellent electrocatalytic behaviour against the electro-oxidation of carbendazim (CBM) in a 0.2 M PBS 3.0 pH. There has been observed a well resolution peak of the CBM with enhancement in the current for the developed GCE. The impact of electroanalytical parameters such as accumulation time, temperature variation, pH, heterogeneous rate, transfer coefficient, sweep rate, activation energy, as well as total count of electrons and protons have been evaluated in the CBM electro-oxidation mechanism. The real samples like water and soil samples were investigated using voltammetric techniques. The developed sensor is sensitive for the investigation of fungicide CBM by the determination of detection and quantification limit of CBM.

A novel sensor based on WO3·0.33H2O nanorods modified electrode for the detection and degradation of herbicide, carbendazim

In the present-day scenario, it is necessary to establish more flexible, effective and selective analytical methods that are easy to operate and less expensive. Cyclic voltammetry (CV) can be a useful technique to assess minute quantity of pollutants and in this work, an effort has been made to detect the trace quantification from the environmental samples. Herein, electrochemical sensor was fabricated using tungsten oxide nanorod (WO3·0.33H2O) for sensitive detection of fungicide, carbendazim (CBZ). Under optimal conditions, while studying the effect of pH on peak current, the highest peak current was observed at pH 4.2. The degradation of CBZ followed the mixed diffusion-adsorption controlled and quasi-reversible processess at the WO3·0.33H2O/GC electrode surface. Using WO3·0.33H2O/GCE sensor in SWV provided the lowest limit of detection (LOD) and limit of quantification (LOQ) values of 2.21 × 10−8 M and 7.37 × 10−8 M, respectively over the concentration ranges of 1.0 × 10−7 M to 2.5 × 10−4 M. The proposed method demonstrates potential applicability of the fabricated sensor for soil and water samples analysis in the management of creating a benign environment.

The effect of radiation in the degradation of carbendazim and azoxystrobin in strawberry

Excess fungicides can trigger many human health problems. Hence, measures for the degradation of fungicide residues are needed. In the present study, the efficiency of gamma radiation (0.5, 1.0, 1.5, 2.0 and 4.0 kGy) in the decomposition of carbendazim and azoxystrobin levels in strawberries was monitored. Irradiated strawberry samples were extracted using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) protocol. Quantification of carbendazim and azoxystrobin was performed using high-performance liquid chromatography. The radiation doses of 1.5, 2.0, and 4.0 kGy degraded 13.17, 15.95, and 27.99% of carbendazim and 25.53, 32.32 and 56.70% of azoxystrobin, respectively. Determination of the radiation dose required to decrease the fungicides by 50% (RD50) revealed that carbendazim was more resistant than azoxystrobin to gamma radiation.

Characterization of a novel carbendazim-degrading strain Rhodococcus sp. CX-1 revealed by genome and transcriptome analyses

The persistence and ecotoxicity of carbendazim residues pose a potential risk to environmental ecology and human health. Here, a novel and highly efficient carbendazim-degrading bacterium Rhodococcus sp. CX-1, capable of utilizing carbendazim as its sole source of carbon and energy, was isolated from contaminated soil. The biodegradation characteristics and metabolic pathways were studied by mass spectrometry, genomic annotation, and transcriptome analysis. The degradation rate of carbendazim by strain CX-1 was 3.98–9.90 mg/L/h under different conditions, and the optimum degradation conditions were 40 °C and pH 7.0. The addition of carbon sources (glucose, fructose, and sucrose, 100 mg/L) could accelerate carbendazim degradation. HPLC-MS/MS identification suggested that carbendazim is first hydrolyzed into 2-aminobenzimidazole and then to 2-hydroxybenzimidazole, and is ultimately mineralized to carbon dioxide. The genome of strain CX-1 contained 6,511,628 bp nucleotides, 2 linear plasmids, 2 circular plasmids, and 6437 protein coding genes. Genome annotation and transcriptome analysis indicated that carbendazim degradation may be regulated by the degradation genes harbored in the chromosome and in plasmid 2, and two different degradation pathways of carbendazim by imidazole ring cleavage or benzene ring cleavage were predicted. This study provided new insight to reveal the biodegradation mechanism of carbendazim; furthermore, strain CX-1 is a promising bioresource for carbendazim bioremediation.

Using electrochemistry coupled to high resolution mass spectrometry for the simulation of the environmental degradation of the recalcitrant fungicide carbendazim

Currently, there is a growing interest in the study of environmental degradation pathways of organic contaminants such as pesticides, with the objective to better understand their potential risk for environmental systems and living organisms. In this context, DFT (conceptual density functional theory) and predictive methods may systematically be used to simplify and accelerate the elucidation of environmental degradation. We report herein the electrochemical behavior/degradation of the carbendazim (CBZ) fungicide widely used to treat cereal and fruit crops. Oxidative degradation of CBZ was studied using an electrochemical flow-through cell directly coupled to a mass spectrometer for rapid identification of CBZ degradation products. The structural elucidation of CBZ oxidation products was based on retention time, accurate mass, isotopic distribution and fragmentation pattern by using LC-HRMS an LC-HRMS2. The most important chemical reactions found to occur in the transformation of CBZ were hydrolysis and hydroxylation. EC-LC-MS and EC-MS analysis has made it possible to highlight the identification of degradation products of CBZ. In addition to previously known transformation products common to those observed during environmental degradation (monocarbomethoxyguanidine, benzimidazole-isocyanate, 2-aminobenzimidazole, hydroxy-2-aminobenzimidazole, hydroxycarbendazim, CBZ-CBZ dimer), two new degradation products were identified in this work: a quinone imine and a nitrenium ion. Electrochemistry mass spectrometry hyphenated techniques represent an accessible, rapid and reliable tool to elucidate the oxidative degradation of CBZ, including reactive degradation products and conjugates.

Post-harvest treatment of carbendazim in Chinese chives using TiO2 nanofiber photocatalysis with different anatase/rutile ratios

Carbendazim residues in Chinese chives were treated by photocatalysis using the following three electrospun TiO2 nanofibers: TTiP/PVP, TTiP/PVAc, and TBOT/PVP. The as-spun fibers were calcined at 500–650 °C to achieve anatase/rutile (A/R) ratios of 100:0, 80:20, 70:30, 50:50, and 30:70. The obtained anatase crystallite sizes were in the range of 13.9–28.1 nm, while the rutile crystallite sizes were 21.1–30.6 nm. The experiments were conducted in glass reactors. These were filled with water and each type of the fiber and irradiated from above by black light lamps for 5 min. Then, 50 g of the samples of Chinese chives was immersed for 5, 15, 30, and 60 min. Carbendazim in the chives was extracted using the matrix solid-phase dispersion (MSPD) method and analyzed using UHPLC. The ˙OH formation from each fiber type was investigated using the coumarin fluorescent probe method. An A/R ratio of 70:30 yielded the highest ˙OH formation, as well as the greatest carbendazim degradation. Rutile plays a crucial role in inhibition of electron-hole recombination and ˙O2− stabilization. The degradation efficiencies for carbendazim from TTiP/PVP, TTiP/PVAc, and TBOT/PVP fibers after a 60-min treatment were 98.6–99.5%, 91.2–97.1%, and 99.5–99.9%, respectively. The TTiP/PVP and TBOT/PVP fibers produced levels of retained carbendazim in the chives that were within EU maximum residue limits of 0.1 mg/kg. The thermal stability of the TTiP/PVAc fiber limited ˙OH formation and carbendazim degradation.

Degradation of Carbendazim in Soil: Effect of Sewage Sludge-Derived Biochars.

Application of biochar in soils can affect the soil properties and, in turn, the fate of pesticides. Batch experiments were conducted to investigate the effect of sewage sludge-derived biochars on the dissipation of a fungicide carbendazim in soil, and the transformation of carbendazim in soil was also studied. Results showed that the dissipation of carbendazim was fastest in a loamy soil SD with a half-life of 11.0 d among the three kinds of soils tested in this study. A dual effect (both acceleration and inhibition) of sewage sludge-derived biochars on carbendazim degradation in soil was reported. The addition of 10% biochars produced at 700 °C (BC 700) in soil could accelerate the carbendazim degradation, but an inhibitory effect was observed for 10% BC 300 or BC 500. Degradation of carbendazim was significantly inhibited when 0.5 or 5% BC 700 was added in soil but accelerated when the amendment ratio of BC 700 was increased to 10%. Such complex effects of the sewage sludge biochar should be taken into consideration in risk assessment of pesticides and the biochar effects on soil remediation. Eight metabolites of carbendazim were characterized, seven of which were reported in unamended soil for the first time. The metabolic pathways of carbendazim in soil are proposed.

Degradation kinetics of carbendazim by Klebsiella oxytoca, Flavobacterium johnsoniae, and Stenotrophomonas maltophilia strains

The fungicide carbendazim is an ecotoxic pollutant frequently found in water reservoirs. The ability of microorganisms to remove pollutants found in diverse environments, soil, water, or air is well documented. Although microbial communities have many advantages in bioremediation processes, in many cases, those with the desired capabilities may be slow-growing or have low pollutant degradation rates. In these cases, the manipulation of the microbial community through enrichment with specialized microbial strains showing high specific growth rates and high rates and efficiencies of pollutant degradation is desirable. In this work, bacteria of the genera Klebsiella, Flavobacterium, and Stenotrophomonas, isolated from the biofilm attached to the packed zones of a biofilm reactor, were able to grow individually in selective medium containing carbendazim. In the three bacteria studied, the mheI gene encoding the first enzyme involved in the degradation of the fungicide carbendazim was found. Studying the dynamics of growth and carbendazim degradation of the three bacteria, the effect of co-formulants was also evaluated. The pure compound and a commercial formulation of carbendazim were used as substrates. Finally, the study made it possible to define the biokinetic advantages of these strains for amendment of microbial communities.

Structural Insights on 2D Gadolinium Tungstate Nanoflake: A Promising Electrocatalyst for Sensor and Photocatalyst for the Degradation of Postharvest Fungicide (Carbendazim).

Gadolinium tungstate (Gd2(WO4)3) has acquired much attention owing to its exclusive transport properties and excellent thermal and chemical stability. In this work, we demonstrate that two-dimensional (2D) gadolinium tungstate nanoflakes (GW Nfs) are synthesized by a coprecipitation method and represent novel architectures for efficient catalysis, which could be used in electrochemical sensing and photocatalytic degradation of the postharvest fungicide carbendazim (CBZ). The physicochemical properties of GW Nfs were studied by using XRD, Raman, TEM, EDX, and XPS, which show the formation of GW as a nanoflake-like structure with a well crystallized nature. The as-prepared GW Nfs revealed an admirable electrochemical response for CBZ detection with an LOD of 0.005 μM, a wide-ranging linear response of 0.02 to 40 μM, and a notable sensitivity of 0.39 μA μM-1 cm-2. Furthermore, the GW-Nf-modified electrode has a good recovery for CBZ in the study of real samples such as rice and soil washed water samples. Moreover, GW Nfs have a promising photocatalytic activity for CBZ degradation. The GW Nfs could degrade CBZ at greater than 98% efficiency and mineralize above 74% of the CBZ molecules in the presence of visible light irradiation with superior stability even after many cycles. Subsequently, the electrochemical and photocatalytic mechanisms were provided in detail.

Influence of humic acid, iron and copper on microbial degradation of fungicide Carbendazim

Abstract Carbendazim (CBZ) is a systemic fungicide utilized for the control fungal diseases in forestry and agricultural crops. Its severe toxicity and residual nature mandated its removal and biodegradation by biological, eco-friendly and sustainable methods. Towards this direction, we searched for CBZ utilizing bacterial strains from the agricultural soils. Based on morphological, biochemical and molecular characterisation the isolates were identified as Streptomyces sp. CB1, Bacillus subtilis CB2, Pseudomonas aeruginosa CB3 and Rhizobium leguminosarum CB4. The effect of CBZ on isolates in the presence and absence of Fe(II), Cu(II) and humic acid was determined. It was found that humic acid supplementation resulted in enhanced and extended growth of bacterial isolates. Among the four isolates, P. aeruginosa CB3 exhibited highest CBZ degradation followed capability by B. subtilis CB2, Streptomyces sp. CB1 and R. leguminosarum CB4. Supplementation with Cu(II) ions resulted in higher degradation of CBZ. However, humic acid was only moderately effective, whereas Fe(II) failed to show any appreciable increase in CBZ degradation by bacterial isolates. Our study suggests that CBZ adapted bacterial strains can offer a biologically and sustainable solution for bioremediation of contaminated agricultural fields and reservoir sites.

Photocatalytic mineralization of carbendazim pesticide by a visible light active novel type-II Bi2S3/BiFeO3 heterojunction photocatalyst

In this study, an efficient photocatalytic route is developed for degradation of carbendazim fungicide under visible light irradiation using Bi2S3/BiFeO3 heterojunction materials as photocatalyst. The heterojunction system prepared by a two-step process contains rhombohedral BiFeO3 and orthorhombic Bi2S3 as crystalline phases. Morphologically, the Bi2S3/BiFeO3 materials contain BiFeO3 nanoplates and Bi2S3 nanorods in close microscopic contact. The Bi2S3/BiFeO3 materials exhibited improved visible light absorption, enhanced charge carrier separation and efficient photocatalytic activity achieving 96% degradation within 2 h of reaction. The mechanistic pathway for carbendazim degradation has been elucidated using GC-Mass analysis and radical scavenger experiments.

Degradation of carbendazim in water via photo-Fenton in Raceway Pond Reactor: assessment of acute toxicity and transformation products.

This study aimed at investigating the degradation of fungicide carbendazim (CBZ) via photo-Fenton reactions in artificially and solar irradiated photoreactors at laboratory scale and in a semi-pilot scale Raceway Pond Reactor (RPR), respectively. Acute toxicity was monitored by assessing the sensibility of bioluminescent bacteria (Aliivibrio fischeri) to samples taken during reactions. In addition, by-products formed during solar photo-Fenton were identified by liquid chromatography coupled to mass spectrometry (UFLC-MS). For tests performed in lab-scale, two artificial irradiation sources were compared (UVλ > 254nm and UV-Visλ > 320nm). A complete design of experiments was performed in the semi-pilot scale RPR in order to optimize reaction conditions (Fe2+ and H2O2 concentrations, and water depth). Efficient degradation of carbendazim (> 96%) and toxicity removal were achieved via artificially irradiated photo-Fenton under both irradiation sources. Control experiments (UV photolysis and UV-Vis peroxidation) were also efficient but led to increased acute toxicity. In addition, H2O2/UVλ > 254nm required longer reaction time (60 minutes) when compared to the photo-Fenton process (less than 1min). While Fenton's reagent achieved high CBZ and acute toxicity removal, its efficiency demands higher concentration of reagents in comparison to irradiated processes. Solar photo-Fenton removed carbendazim within 15min of reaction (96%, 0.75kJL-1), and monocarbomethoxyguanidine, benzimidazole isocyanate, and 2-aminobenzimidazole were identified as transformation products. Results suggest that both solar photo-Fenton and artificially irradiated systems are promising routes for carbendazim degradation.

Assessing Brevibacillus sp. C17: An indigenous isolated bacterium as bioremediator for agrochemical effluent containing toxic carbendazim

An indigenous bacterium Brevibacillus panacihumi C17 was isolated from agrochemical waste effluent (Kolkata area, India). The isolate showed an efficient degradation capacity of a toxic fungicide Carbendazim (CBZ) (300 mg L−1), frequently used in agricultural field in that area. The present research is one of the very few growth dynamics studies showing the substrate utilization rate (Us = 0.91) of the bacterium, also the specific growth rate which was observed to be 0.173 h−1. Degradation studies revealed the maximum degradation (87.25%) was obtained at 100 mg L−1 at incubation time of 36 h, pH 7.0 and speed of 180 rpm beyond this the degradation was found to decline. The kinetic growth parameter modeling indicated that the process showed best fitting of the experimental data in Logistic function (R2 = 0.94) as compared to others. Analytical studies of SEM, FTIR and XRD revealed the CBZ degradation mechanism by bio-sorption process occurring on the outer cell surface using adsorption energy. It was observed that the bio-sorption process followed the DKR isotherm model (R2 = 0.921). Strain Brevibacillus sp. C17 was observed to reduce chemical oxygen demand (COD) by 85± 2.5% of the agrochemical waste effluent (COD 880 mg L−1) within 50 h of batch treatment. One of the important observations is the toxicity analysis of the real effluent and aqueous solution of CBZ after the bacterial treatment which indicated the environmental friendly behavior of the bio-treatment.