Toxicity Of Degradation Products Research Articles

Gravity-driven Fe-doped CoTiO3/SiO2 fiber membrane with open catalytic network: Activation of peroxymonosulfate and efficient pollutants removal

Constructing a robust catalytic membrane with simultaneous fast liquid transport and efficient organic pollutant degradation is appealing for efficient organic wastewater treatment. Herein, Fe-doped CoTiO3 grew uniformly on the SiO2 fiber membrane to form a catalytic membrane (FCTSM). Benefiting from the great water wettability, FCTSM facilitated fast water transport with low energy consumption and exhibited high physical separation performance (98.4% rejection of oil in the emulsion). The catalytic active sites were fully exposed on membrane surface, which could easily react with peroxymonosulfate and target pollutants. Under the gravity-driven permeation, FCTSM performed decent catalytic degradation property (e.g., 96.3% removal of nimesulide with the flux of 300 L/m2·h) in the presence of peroxymonosulfate. Electron paramagnetic resonance (EPR) spectra and quenching tests found that SO4•− and 1O2 were involved in pollutant degradation, and the possible degradation pathway of nimesulide was investigated. Besides, the toxicity analyses based on quantitative structure–activity relationship (QSAR) verified the reduced toxicity of degradation products. This work provides an insight into the design of multifunctional membranes and advances the potential applications of heterogeneous catalytic oxidation in environmental remediation.

Removal of chloramphenicol in water by an improved water falling film dielectric barrier discharge reactor: Performance, mechanism, degradation pathway and toxicity evaluation

Chloramphenicol (CAP) is a common antibiotic, which is difficult to be removed in water environment and has caused huge environmental risks. Herein, an improved water falling film dielectric barrier discharge (WFFDBD) reactor was built to treat 20 L of CAP wastewater. The effects of operating parameters of the reactor on CAP degradation were investigated, the main reactive species for CAP degradation were identified, the intermediates and degradation pathway of CAP were analyzed, and the toxicity of degradation products of CAP was evaluated by quantitative structure activity relationship (QSAR) models. The results show that CAP degradation efficiency was significantly increased by covering medical gauze. At 370 W of discharge power, CAP degradation efficiency was 88.7% and 59.9% after 140 min treatment with and without the gauze, and the energy efficiency of WFFDBD reactor with medical gauze was 2.53 times higher than that without medical gauze. The medical gauze significantly increased the yield of the reactive species of WFFDBD. Correlation matrix analysis showed that the contribution of H2O2, O3 and ·OH for CAP removal followed the order of ·OH > H2O2> O3. Moreover, O2⋅− and ·H were also the key species for CAP degradation. A possible degradation pathway was given based on the measured degradation products. The developmental toxicity of CAP and its degradation products were quantified, and the results indicate the toxicity of CAP wastewater was weakened after WFFDBD treatment.

Densifying lignocellulosic biomass with sulfuric acid provides a durable feedstock with high digestibility and high fermentability for cellulosic ethanol production

Agricultural residues (e.g. corn stover (CS)) representing a huge lignocellulosic biomass waste are regarded as a promising renewable resource that can be converted to fuels and chemicals via biochemical route. Nevertheless, the unfavorable properties, such as low bulk density, contamination by microorganisms, fluffy and thereby difficult to handle, cause huge problems for biomass logistics and biomass conversion. Furthermore, traditional biomass pretreatment methods often use severe conditions, consume much energy, difficult to scale up and generate a feedstock with many toxic degradation products that inhibit fermentation. In this study, we developed a novel, low-cost and easy-to-implement pretreatment method: “Densifying Lignocellulosic biomass with acidic Chemicals (DLC)” on CS. The DLC-CS owning a uniform shape showed a bulk density 4 times higher compared to loose CS and was highly resistant to microbial contamination, which greatly facilitates biomass handling, transportation and storage. DLC-CS after regular steam autoclave treatment at 121 ○C exhibited high enzymatic digestibility and much higher fermentability compared to traditional dilute acid pretreatment. An ethanol titer as high as 68.1 g/L was achieved without washing or detoxification of the pretreated biomass. The superior performances of DLC for biomass logistics and biomass conversion render it very promising for industrial use.

DLC(sa) and DLCA(sa) pretreatments boost the efficiency of microbial lipid production from rice straw via Trichosporon dermatis

Microbial lipids derived from lignocellulosic biomass are attractive feedstocks for biodiesel production. However, toxic degradation products generated by pretreatment greatly inhibited lipid fermentation. Herein, two pretreatment methods, i.e. densifying lignocellulosic biomass with sulfuric acid (DLC(sa)) and densifying lignocellulosic biomass with sulfuric acid followed by autoclave (DLCA(sa)), were developed on rice straw (RS) for lipid production. The conditions of DLCA(sa) pretreatment, including sulfuric acid dosage, dry biomass loading and autoclave time, were optimized by response surface methodology. High fermentable sugar yields with low inhibitor concentrations were obtained on DLC(sa) pretreated RS (DLC(sa)-RS) and DLCA(sa) pretreated RS (DLCA(sa)-RS) via enzymatic hydrolysis at a high solid loading of 30 wt%. Lipid titers of as high as 28.9 g/L and 31.0 g/L, with lipid yields of 0.22 g/g and 0.24 g/g consumed sugar, were achieved when RS was pretreated by DLC(sa) and DLCA(sa), respectively. This study demonstrated efficient microbial lipid production from lignocellulosic biomass without washing or detoxification steps.

Development of DLC and DLCA pretreatments with alkalis on rice straw for high titer microbial lipid production

Microbial lipid production from lignocellulosic biomass is largely impeded by unsatisfactory fermentation performance due to the presence of toxic degradation products generated by pretreatment. DLC (Densifying Lignocellulosic biomass with Chemicals) pretreatment completed at room temperature, generating fewer degradation products, showed great potentials for lignocellulosic biorefineries. This work developed DLC pretreatment with sodium hydroxide and calcium hydroxide on rice straw (RS) for microbial lipid production. Conditions for steam autoclave on DLC-RS (i.e. DLCA treatment) were optimized using response surface methodology. High solid loading enzymatic hydrolysis and lipid fermentations by Trichosporon dermatis 32,903 together with mass balances were performed. Lipid fermentations were successfully conducted, for the first time, on pretreated biomass at a solid loading as high as 35 wt.% without washing or detoxification. Lipid titers as high as 28.3 g/L and 29.5 g/L were achieved on DLC-RS and DLCA-RS, respectively, with lipid yields of 0.24 and 0.23 g/g consumed sugar.

Current knowledge of the degradation products of tattoo pigments by sunlight, laser irradiation and metabolism: a systematic review.

The popularity of tattooing has increased significantly over recent years. This has raised concerns about the safety of tattoo inks and their metabolites/degradation products. The photolytic and metabolic degradation of tattoo pigments may result in the formation of toxic compounds, with unforeseen health risks. A systematic literature review was undertaken to determine the current state of knowledge of tattoo pigments' degradation products when irradiated with sunlight, laser light or metabolised. The review demonstrates that there is a lack of knowledge regarding tattoo pigment degradation/metabolism, with only eleven articles found pertaining to the photolysis of tattoo pigments and two articles on the metabolism of tattoo pigments. The limited research indicates that the photolysis of tattoo pigments could result in many toxic degradation products, including hydrogen cyanide and carcinogenic aromatic amines.

Effect of ozone application on the removal of pesticides from grapes and green bell peppers and changes in their nutraceutical quality

The present study evaluates the efficacy of ozonated water for the removal of pesticide residues in grapes and green bell peppers. Fruit fortified with pesticides (azoxystrobin, chlorothalonil, chlorpyrifos, cypermethrin, hexaconazole and methyl parathion) were subjected to 15 and 30 min aqueous ozone treatment. GC analysis of ozonated fruits showed a 48.67% to 96.95% decrease in pesticide residues of different pesticides. Methyl paraoxon, a toxic degradation product of methyl parathion, was detected in the ozonated water sample. To assess the effect of ozonation on the nutraceutical quality of fruits, the concentrations of eleven polyphenols and ascorbic acid were analyzed. The individual polyphenols showed different trend in 15 and 30 min treatment. Overall, there was an increase in the levels of all the polyphenols in grapes after 30 min ozonation treatment. In peppers, there was a net increase in quercetin, quercetin-3-O-glucoside, rutin and kaempferol in 30 min while other polyphenols were decreased. The ascorbic acid content of both the fruits was decreased by more than 70% upon ozonation. Thus, ozonation treatment was effective in pesticide removal. However, it changed the nutraceutical quality of grapes and green bell peppers.

(Invited) High Performance Single Conducting Polymer Electrolytes for Lithium Metal Batteries

Lithium-based batteries are a key technology for successfully transitioning from depleting fossil fuels to renewable energy sources, particularly in meeting the demands of a highly mobile society. Nevertheless, the commonly employed liquid organic electrolytes are highly flammable and release toxic degradation products[1]. Solid electrolytes are a promising alternative, since they offer an improved safety and potentially suppress dendritic lithium deposition[2]. Among them, due to their flexibility and modularity, solid polymer electrolytes (SPEs) are excellent candidates. For their commercial implementation, however, one must simultaneously ensure acceptable ionic conductivity (>10-4 S cm-1 at 25 °C), high mechanical strength, and an electrochemical stability window of at least 4-5 V. Conventional polymer electrolytes based on poly(ethylene oxide) (PEO) consist of a lithium salt dissolved in the polymer. Frequently, also a plasticizer is added to enhance the segmental relaxation-dependent charge transport by lowering the glass transition temperature (Tg)[3]. The need for a conducting salt, however, results in transference numbers (t+) far below 0.5. This leads to charge concentration gradient and reversed cell polarization issues, which worsen the long-term cycling stability[4]. SPEs with t+ = 1, also known as ‘single-ion polymer electrolytes’ (SIPEs), might overcome these issues. The simplest approach to achieve single-ion conductivity is to covalently tether the anion to the polymer backbone (so-called ‘ionomers’), thus ensuring that the only mobile species is the cation. Nevertheless, the conductivity of these systems is typically very low (10− 8 to 10− 7 S cm− 1 at 25 °C)[5 ] and despite the ten-fold increase achieved through optimizing the ionomer structure by introducing weakly coordinating anionic species (∼10− 6 S cm− 1 at 25 °C)[ 6] or designing block or grafted copolymers, their employment remains unfeasible. Moreover, for most block copolymer-based SIPEs, the anion is tethered to the rigid block, while the Li+ conduction occurs in the microphase-separated PEO block. Consequently, adequate conductivities are achievable only in the disordered state above the melting point of the PEO phase, so that the phase separation and, accordingly, the mechanical properties provided by the rigid block vanish. In this presentation we give SIPE that we recently synthetized[7,8] with very efficient charge transport pathways, high electrochemical stability and an ionic conductivity approaching that of liquid organic electrolytes. Moreover, these SIPEs allowed for lithium stripping/plating for more than 1000 h with a remarkably low overpotential and cycling of NMC811 with high reversible capacity at various temperatures, including 20 °C and even 0 °C, for more than 500 cycles without substantial capacity fading when applying an optimized charging mode. These are very remarkable and original results, since the materials’ properties are nicely tailorable with regard to the ionomer structure, charge carrier density, phase separation, and morphological appearance. The polymer nanostructure and cell performances are correlated. References Hammami, A., Raymond, N. & Armand, M. Nature 424, 635–636 (2003).Aricò, A. S., Bruce, P., Scrosati, B., Tarascon, J.-M. & Van Schalkwijk, W. Mater. 4, 366–377 (2005).Osada, I., De Vries, H., Scrosati, B. & Passerini, S. Chemie - Int. Ed. 55, 500–513 (2016).Tikekar, M. D., Choudhury, S., Tu, Z. & Archer, L. A. Energy 1, 16114 (2016).Shaplov, A. S., Marcilla, R. & Mecerreyes, D. Acta 175, 18–34 (2015).Xu, K. Rev. 114, 11503–11618 (2014).Nguyen h-D, Kim G-K, Shi J, Elie Paillard, Judeinstein P., Lyonnard S., Bresser D., Iojoiu C. Energy & Environmental Science, 11, 3298-3309, (2018).Chen, D. Steinle, H-D. Nguyen, J-K. Kim, A. Mayer, J. Shi, E. Paillard, C. Iojoiu, S. Passerini, D. Bresser, NanoEnergy, 77, 105121, (2020).

Effect of Rhodotorula mucilaginosa on patulin degradation and toxicity of degradation products

ABSTRACT Rhodotorula mucilaginosa is an antagonistic yeast for which our research team has recently reported interesting biocontrol activities against blue mould decay of apples and a strong ability to decrease the patulin concentration in vivo. However, the possible mechanisms of patulin degradation by R. mucilaginosa and the toxicity of patulin degradation products remain unclear. In this study, the effect of R. mucilaginosa on patulin degradation and toxicity of degradation products were investigated, the results showed that viable cells of R. mucilaginosa are essential to patulin degradation. Also, R. mucilaginosa eliminated patulin without adsorbing it through its cell wall. The extracellular metabolites of R. mucilaginosa stimulated by patulin showed little degradation activity for patulin. Cycloheximide addition into the medium significantly decreased the patulin degradation capacity of R. mucilaginosa cells. The main patulin degradation product by R. mucilaginosa was ascladiol, which was proved non-toxic to human hepatoma (HepG2) cells at 0.625–10 g/mL. Furthermore, toxicological analysis using a confocal laser scanning microscope revealed that the degradation product induced cellular apoptosis to a lesser extent than patulin itself. This result offers an innovative method to detoxify patulin and limit the risks of patulin in fruits and vegetables using R. mucilaginosa.

Biodegradation of the organophosphate dimethoate by Lactobacillus plantarum during milk fermentation

Bioremediation of pesticides in contaminated foodstuffs using probiotics has attracted great attention in recent years, but some intermediate products may have profound effects on the toxicity of treated food. Therefore, this work studied the degradation mechanism of dimethoate in milk by L. plantarum, and analyzed the toxicity of degradation products. The results showed that under the optimal conditions, L. plantarum can degrade 81.28% of dimethoate. Dimethoate had high binding affinities to phosphatase with the free energy of –16.67 kcal/mol, and amino acid residues, Gln375 and SER415 played important roles in the catalysis process. Five degradation products were identified using UPLC-QTOF/MS, and their toxicity was estimated using quantitative structure–activity relationship models. Some intermediate products were predicted to be toxic, which should not be ignored, but the overall toxicity of milk decreased after fermentation. Furthermore, the pH and titratable acidity of the fermented milk were 4.25 and 85 ◦T, respectively.

Simultaneous estimation of troxerutin and calcium dobesilate in presence of the carcinogenic hydroquinone using green spectrofluorimetric method.

In the present study, we conducted two facile and highly sensitive spectrofluorimetric approaches in order to quantify the vasoprotective agents; troxerutin (TROX) and calcium dobesilate (DOB) in the presence of hydroquinone (HQ) (as a highly toxic impurity and potential degradation product of DOB) in commercial formulations and human plasma. The first approach relies simply on using ethanol as an eco-friendly solvent for the estimation of DOB at 345 nm after being excited at 305 nm. The linearity was carefully investigated between DOB concentration and the relative fluorescence intensity in the range of 0.05–0.8 µg ml−1. Due to the high method simplicity and sensitivity, applying the first approach to quality control analysis and spiked human plasma samples with mean % recoveries 100.74 ± 3.71 adds another merit. The second approach involved rapid conventional fluorimetric estimation of ethanolic TROX solution in TROX/DOB combined dosage forms at 455/350 nm (emission/excitation) with a linear calibration chart covering the range of 0.1–1.2 µg ml−1. Moreover, the second approach involved a comprehensive study in a trial to solve the problem of superposition of DOB and HQ graph adopting the first derivative synchronous fluorimetric mechanism in ethanol at Δλ = 60 nm. Therefore, DOB was measured at 286 and 323 nm, while HQ could be quantitated at 301 nm. The Beer–Lambert Law has complied over the ranges of 0.1–1.0 and 0.02–0.4 µg ml−1 for DOB and HQ, respectively. Guidelines adopted by the International Council of Harmonization (ICH) were used to validate the target approaches. The developed methods are more convenient for routine quality control laboratory instead of the time-consuming and sophisticated reported techniques. Moreover, different aspects of evaluating the greenness of the proposed approaches were conducted to have a complete image of their environmental impact.

Evaluation of the toxicity and chemical alterations of deoxynivalenol degradation products under ozone treatment

Here, we studied the ozonolysis of deoxynivalenol (DON) in saturated aqueous ozone. We found that ozone can play an important role in the oxidation and degradation of DON. The reaction reached its peak within 5 min of treatment, and the degradation rate was approximately 70%. Toxicity analysis (CCK-8 analysis, ROS analysis, and apoptosis analysis) revealed that DON and saturated aqueous ozone treatments did not significantly change the toxicity of degradation products, and both could induce a decrease in the viability of A549 cells. The results of the metabolomics and cytotoxicity analysis were consistent. We used the Q Exactive Focus high-resolution liquid chromatography-mass spectrometry system to identify degradation products. Among the four identified degradation products, only the epoxy groups at the C12, C13 positions of C15H20O9 were opened. Because the epoxy groups at the C12, C13 positions in most degradation products were not opened based on the toxicity mechanism of DON, the toxicity of DON was not significantly reduced.

UV treatment for degradation of chemical contaminants in food: A review.

Application of ultraviolet (UV) irradiation for the degradation of chemical contaminants in food products has gained more and more interest in the past two decades. The majority of the research in this field was on mycotoxins, especially aflatoxins and patulin, with limited studies on pesticide residues and other chemical contaminants in food. These studies have been focused on identifying the structure and toxicity of degradation products, investigating the influence of UV treatment factors on the degradation efficiency, determining the impact of UV treatment on the quality of food products, and developing updated UV treatment methods such as TiO2 induced photocatalytic degradation. The summary of published literatures provided insights into future research opportunities in this area, which include determining a standard for the UV treatment description, working with naturally contaminated samples rather than artificially spiked samples, conducting pilot plant or industrial scale studies, examining more targets and conducting multi-targets studies, and developing more innovative methods for UV treatment.

Evaluation of the Multimycotoxin-Degrading Efficiency of Rhodococcus erythropolis NI1 Strain with the Three-Step Zebrafish Microinjection Method.

The multimycotoxin-degrading efficiency of the Rhodococcus erythropolis NI1 strain was investigated with a previously developed three-step method. NI1 bacterial metabolites, single and combined mycotoxins and their NI1 degradation products, were injected into one cell stage zebrafish embryos in the same doses. Toxic and interaction effects were supplemented with UHPLC-MS/MS measurement of toxin concentrations. Results showed that the NI1 strain was able to degrade mycotoxins and their mixtures in different proportions, where a higher ratio of mycotoxins were reduced in combination than single ones. The NI1 strain reduced the toxic effects of mycotoxins and mixtures, except for the AFB1+T-2 mixture. Degradation products of the AFB1+T-2 mixture by the NI1 strain were more toxic than the initial AFB1+T-2 mixture, while the analytical results showed very high degradation, which means that the NI1 strain degraded this mixture to toxic degradation products. The NI1 strain was able to detoxify the AFB1, ZEN, T-2 toxins and mixtures (except for AFB1+T-2 mixture) during the degradation experiments, which means that the NI1 strain degraded these to non-toxic degradation products. The results demonstrate that single exposures of mycotoxins were very toxic. The combined exposure of mycotoxins had synergistic effects, except for ZEN+T-2 and AFB1+ZEN +T-2, whose mixtures had very strong antagonistic effects.

Characterization and toxicity evaluation of degradation products of febantel

BackgroundThe aim of the present work was to determine potential toxicity of degradation products of febantel generated under different stress conditions mentioned in guideline Q1A (R2) laid down by International Council for Harmonization (ICH). The stability behavior of febantel was studied by subjecting it to hydrolytic, oxidative, photolytic and thermal forced degradation conditions.ResultsFive degradation products (DPs) were observed which were resolved using high-performance liquid chromatography (HPLC) and characterized by LC-MS/MS using positive mode of electrospray ionization. The chromatographic separation was carried out on Hypersil® BDS C18 (150 × 4.6 mm, 5 μm) column. Optimum resolution was obtained using ammonium formate buffer (10 mM, pH 3.5) and acetonitrile programmed in gradient elution mode at 281.0 nm using photodiode array detector.ConclusionThe drug was found susceptible to degradation under all the stress conditions except thermal and oxidative stress. Five major unknown degradation products DP–I, DP–II, DP–III, DP–IV, and DP–V generated under photolytic, alkali, and acidic stress condition were identified and characterized by LC-MS/MS. The drug and identified degradation products were screened for prediction of in-silico toxicity using software viz. Swiss ADME, OSIRIS Property Explorer and Pro Tox II which indicated overall no toxicological concerns.Graphical abstract

Ecological and economic comparative evaluation of plasmochemical and ultraviolet destruction of the anionic surfactants

Among the huge number of pollutants in aquatic ecosystems, surfactants can be singled out. Among them, the largest number used in everyday life and in various industries are anionic surfactants. It should also be noted their negative impact on wastewater treatment processes and, more importantly, on the environment. One of the approaches aimed at reducing the negative impact of surfactants on water systems is the introduction of reliable and effective methods of wastewater treatment from surfactants. The current environmental situation dictates the need for deep (destructive) treatment of wastewater from pollutants, regardless of the volume of wastewater discharged into reservoirs, to comply with their content of the MPC. Today, the most advanced among the destructive methods are methods based on innovative oxidative processes that allow the complete decomposition of pollutants or convert them into forms capable of further biodegradation. The essence of these technologies is the oxidation of toxicants by highly reactive particles of activated oxygen, which due to various processing methods, are generated directly in the reaction system. Of particular interest are technologies in which highly active particles of activated oxygen are formed directly during processing and do not require the use of additional chemical reagents (oxidants, catalysts). Among them are the action of vacuum (λ<200 nm) ultraviolet radiation (VUV) and various electric discharge methods.However, the large-scale application of these processes for the treatment of wastewater is still limited in particular by the fact that the mechanisms of decomposition of surfactants using these processes are insufficiently studied. The complexity of studying the efficiency of oxidative destruction of surfactants is due to the multi-stage oxidation process, the formation of mixtures of various intermediate products, the composition of which is not fully established. The toxicity of surfactant degradation products is also unknown, which is an important criterion for water purification. Another determining criterion of efficiency for the operation of treatment plants is their efficiency.The aim of the article is to conduct a comparative assessment of the environmental friendliness and cost-effectiveness of plasma-chemical and ultraviolet destruction of anionic surfactants.Еcological and economic comparative evaluation of plasma chemical and ultraviolet destruction of anionic surfactants was carried out by using as an example an aqueous solution of sodium dodecyl sulfate CH3(CH2)11OSO3Na ("Serva") with a concentration of 10 mg/dm3.As a result of experiments and calculations, it was found that VUV radiation does not lead to the formation of toxic degradation products when purifying water from anionic surfactants. When using corona discharge, toxic decomposition products can be formed in sodium dodecyl sulfate solutions, which cause chronic toxicity of the solution. Comparison of the values of specific energy consumption showed a much higher efficiency of the UV lamp DRB-20 in the destruction of anionic surfactants in comparison with the positive corona discharge, as the magnitude of specific energy consumption for the lamp is 3.67´10-4 kW∙h/dm3, and for the plasma generator - 4,4´10-3 kW∙h/dm3. It is also shown that in terms of chemical efficiency, water purification from anionic surfactants is more effective when using VUV radiation than positive corona discharge, because this value for VUV is almost 18 times higher than the same indicator when using a plasma generator.Due to the high need for the introduction of new efficient, cost-effective and safe methods of water purification from surfactants in further studies it is planned to increase the efficiency of surfactant destruction in aqueous solutions through the use of transition metal catalysts (TiO2). This approach will help to increase the concentration of reactive oxygen species, namely hydroxyl radicals and achieve a much better and faster effect of purification of aqueous solutions from surfactants or other contaminants.

Emergence of cold plasma and electron beam irradiation as novel technologies to counter mycotoxins in food products

Today, mycotoxins are considered a serious risk for human health and the economy around the world. Hence, dealing with them in such a way as to minimise damage to food and plant materials has become an important issue. Cold atmospheric plasma and electron beam irradiation are updated and non-thermal technologies, which are recently used in detoxification of mycotoxins. Both of these technologies have several unique features that turn them into efficient methods for degrading mycotoxins. Therefore, the main purpose of the present study is exhibiting the detoxification power of these methods and parameters affecting their activity. Besides, their advantages, generating systems, activity mechanism, and the toxicity of degradation products are also reviewed.

Glucosinolate Biosynthesis and the Glucosinolate–Myrosinase System in Plant Defense

Insect pests represent a major global challenge to important agricultural crops. Insecticides are often applied to combat such pests, but their use has caused additional challenges such as environmental contamination and human health issues. Over millions of years, plants have evolved natural defense mechanisms to overcome insect pests and pathogens. One such mechanism is the production of natural repellents or specialized metabolites like glucosinolates. There are three types of glucosinolates produced in the order Brassicales: aliphatic, indole, and benzenic glucosinolates. Upon insect herbivory, a “mustard oil bomb” consisting of glucosinolates and their hydrolyzing enzymes (myrosinases) is triggered to release toxic degradation products that act as insect deterrents. This review aims to provide a comprehensive summary of glucosinolate biosynthesis, the “mustard oil bomb”, and how these metabolites function in plant defense against pathogens and insects. Understanding these defense mechanisms will not only allow us to harness the benefits of this group of natural metabolites for enhancing pest control in Brassicales crops but also to transfer the “mustard oil bomb” to non-glucosinolate producing crops to boost their defense and thereby reduce the use of chemical pesticides.

Removal of atrazine in catalytic degradation solutions by microalgae Chlorella sp. and evaluation of toxicity of degradation products via algal growth and photosynthetic activity

Degradation solutions containing atrazine need to be further purified before they are discharged into the aquatic environment. With the objectives of evaluating removal capacity of the microalga Chlorella sp. toward atrazine in degradation solutions and toxicity of the degradation products, we investigated the removal efficiency (RE) and bioaccumulation of atrazine in the microalgae after an 8 d exposure to diluted degraded solutions containing 40 μg/L and 80 μg/L of atrazine as well as degradation products in the present study. Moreover, pure atrazine solutions with similar concentrations were simultaneously inoculated with the microalgae in order to distinguish the influence of the products. The photocatalytic degradation results showed that 31.4% of atrazine was degraded after 60 min, and three degradation products, desisopropyl-atrazine (DIA), desethyl-atrazine (DEA), and desethyl-desisopropyl-atrazine (DEIA) were detected. After an 8-d exposure, 83.0% and 64.3% of atrazine were removed from the degraded solutions containing 40 μg/L and 80 μg/L of atrazine, respectively. In comparison with the control, i.e., pure atrazine solution with equal concentration, Chlorella sp. in the degraded atrazine solution showed lower RE and growth rate. The photosynthetic parameters, especially performance index (PIABS), clearly displayed the differences between treatments. The values of PIABS of Chlorella sp. cultured in degradation atrazine for 8 days were significantly lower (P < 0.01) than that in the corresponding pure atrazine, suggesting potential inhibitory effect of degradation products on the microalgae. Atrazine and the degradation products inhibited algal photosynthesis via depressed light absorption and electron transport, and reduced utilization of light energy via energy dissipation. Our results demonstrated that microalgae Chlorella sp. had an encouraging atrazine removal potential and the degradation products of atrazine may inhibit algal growth and removal capability. This study may be useful for the application of microalgae in herbicide wastewater treatment and understanding algal removal of atrazine in natural aquatic environment.

Biodegradation of malachite green by a novel laccase-mimicking multicopper BSA-Cu complex: Performance optimization, intermediates identification and artificial neural network modeling

In this work, a soluble biopolymer was prepared by conjugating the bovine serum albumin (BSA) with transition metal ion (Cu2+). BSA-Cu complex was synthesized and characterized using UV–vis absorption, fluorescence and ATR-FTIR spectroscopies. A colorimetric guaiacol oxidation based method, was used to study the catalytic activity of complex and the results indicated its laccase-like activity. Compared with laccase, BSA-Cu complex showed a higher Km value and a similar Vmax value at the same mass concentration. Also, the ability of the BSA-Cu complex to decolorize malachite green (MG) was tested and the results showed that the complex was able to complete the decolorization process of MG within 30 min. Using gas chromatography/mass spectrometry (GC−MS) the resultant metabolites of MG degradation were analyzed and the toxicity of degradation products was assessed against Escherichia coli and Bacillus subtilis. The results confirmed the formation of less toxic products after degradation of MG by BSA-Cu complex. To predict the decolorization efficiency (DE%) of MG, an artificial neural network (ANN) was designed with five, five and one neurons in the input, hidden and output layers, respectively. The obtained results showed the ability of the designed ANN to predict MG removal successfully.