Streptomyces as a Novel Biotool for Azo Pigments Remediation in Contaminated Scenarios.

BACKGROUND: Azo pigments are widely used in the textile and leather industry, and they generate diverse contaminants (mainly in wastewater effluents) that affect biological systems, the rhizosphere community, and the natural activities of certain species. METHODS: This review was performed according to the Systematic Reviews and Meta Analyses (PRISMA) methodology. RESULTS: In the last decade, the use of Streptomyces species as biological azo-degraders has increased, and these bacteria are mainly isolated from mangroves, dye-contaminated soil, and marine sediments. Azo pigments such as acid orange, indigo carmine, Congo red, and Evans blue are the most studied compounds for degradation, and Streptomyces produces extracellular enzymes such as peroxidase, laccase, and azo reductase. These enzymes cleave the molecule through asymmetric cleavage, followed by oxidative cleavage, desulfonation, deamination, and demethylation. Typically, some lignin-derived and phenolic compounds are used as mediators to improve enzyme activity. The degradation process generates diverse compounds, the majority of which are toxic to human cells and, in some cases, can improve the germination process in some horticulture plants. CONCLUSIONS: Future research should include analytical methods to detect all of the molecules that are generated in degradation processes to determine the involved reactions. Moreover, future studies should delve into consortium studies to improve degradation efficiency and observe the relationship between microorganisms to generate scale-up biotechnological applications in the wastewater treatment industry.

Unraveling the molecular response of Brassica napus hairy roots in the active Naphthol blue-black removal: Insights from proteomic analysis.

In vitro plant cultures are able to remove and metabolise xenobiotics, making them promising tools for decontamination strategies. In this work, we evaluated Brassica napus hairy roots (HRs) to tolerate and remove high concentrations of the azo dye Naphthol Blue-Black (NBB). Experiments were performed using both growing and resting culture systems at different pHs. Reuse of HRs biomass was evaluated in successive decolourisation cycles. Proteomics was applied to understand the molecular responses likely to be involved in the tolerance and removal of NBB. The HRs tolerated up to 480 µg mL-1 NBB, and 100 % removal was achieved at 180 µg mL-1 NBB after 10 days using both culture systems. Interestingly, the HRs are robust enough to be reused, showing 55-60 % removal even after three reuse cycles. The highest dye removal rates were achieved during the first 2 days of incubation, as initial removal is mainly driven by passive processes. Active mechanisms are triggered later by regulating the expression of proteins with different biological functions, mainly those related to xenobiotic metabolism, such as hydrolytic and redox enzymes. These results suggest that B. napus HRs are a robust tool that could make a significant contribution to textile wastewater treatment.

Assessment of potato surpluses as eco-friendly adsorbent for removal of Orange II: optimization and kinetic modelling at different pH values.

Orange II, an azo dye used in textile and leather industries, is toxic and contributes to reducing dissolved oxygen in water. In this sense, agri-food waste adsorbents offer efficient, cost-effective dye removal. In this study, potato surpluses were evaluated as adsorbents for the removal of Orange II at 22 °C and pH values between 4 and 9. The adsorbents were characterized by their morphology, elemental composition, infrared spectra, and point of zero charge. Adsorption isotherms were analysed using Langmuir and Freundlich models, revealing that the Langmuir equation (0.933 < r2 > 0.882) better described the adsorption process compared to the Freundlich model (0.909 < r2 > 0.852). The maximum adsorption capacity at pH 4 was 1.1 and 2.3 times higher than at pH 7 and 9, respectively. This increased capacity at pH 4 was due to favourable electrostatic interactions between the cationic adsorbent surface and the anionic dye. A kinetic model was developed to understand the adsorption dynamics of Orange II, demonstrating high accuracy with coefficients of determination (r2) exceeding 0.99 across various pH values. The predictions of the kinetic model aligned well with the Langmuir isotherm results, indicating a strong theoretical foundation. The critical contact time required to achieve the minimum adsorbent concentration necessary for meeting a discharge limit of 14.7 mg L-1 was determined using both the Langmuir and kinetic models. Simulation profiles showed that when the adsorbent concentration was increased from 12 to 40 g L-1, the contact time necessary to achieve the discharge limit decreased from 26 to 3.35 h, highlighting the trade-off between contact time and cost. This study offers a cost-effective solution for wastewater treatment and presents a robust model for optimizing batch adsorption processes, marking a significant advancement in using potato surpluses for dye removal.

Efficient electrochemical advanced degradation of Red CL and Red WB dyes from the tanning industry using a boron-doped diamond anode.

Electrochemical oxidation (EO), electro-Fenton (EF), and photoelectro-Fenton (PEF) with a BDD anode have been comparatively assessed to remediate solutions of Red CL and/or Red WB azo dyes from real raw water. For the EO process in 50 mM Na2SO4 at pH 3.0, the main oxidant was the heterogeneous •OH generated at the anode, whereas in EF and PEF, the cathodic production of H2O2 and the addition of 0.50 mM Fe2+ catalyst additionally originated homogeneous •OH that enhanced the oxidation of organics. In PEF, the solution was illuminated with a 6 W UVA light. An almost total discoloration was always found operating with a 1:1 mixture of 200 mg L-1 of both dyes in 60 min, whose efficiency increased in the order of EO < EF < PEF. The HPLC analysis of the dye mixture treated by PEF disclosed that its degradation process agreed with its discoloration. A high 74% of COD was reduced due to the oxidative action of hydroxyl radicals and the photolysis of final Fe(III)-carboxylate species with UVA irradiation. The process was accompanied by an energy consumption of 0.76 kWh (g COD)-1, a value similar to the energy consumed by the applied UVA light.

Two protocols for the detection of oleaginous bacteria using Oil Red O.

The selection of oleaginous bacteria, potentially applicable to biotechnological approaches, is usually carried out by different expensive and time-consuming techniques. In this study, we used Oil Red O (ORO) as an useful dye for staining of neutral lipids (triacylglycerols and wax esters) on thin-layer chromatography plates. ORO could detect minimal quantities of both compounds (detection limit, 0.0025 mg of tripalmitin or 0.005 mg of cetylpalmitate). In addition, we developed a specific, rapid, and inexpensive screening methodology to detect triacylglycerol-accumulating microorganisms grown on the agar plate. This staining methodology detected 9/13 strains with a triacylglycerol content higher than 20% by cellular dry weight. ORO did not stain polyhydroxyalkanoates-producing bacteria. The four oleaginous strains not detected by this screening methodology exhibited a mucoid morphology of their colonies. Apparently, an extracellular polymeric substance produced by these strains hampered the entry of the lipophilic dye into cells. The utilization of the developed screening methodology would allow selecting of oleaginous bacteria in a simpler and faster way than techniques usually used nowadays, based on unspecific staining protocols and spectrophotometric or chromatographic methods. Furthermore, the use of ORO as a staining reagent would easily characterize the neutral lipids accumulated by microorganisms as reserve compounds. KEY POINTS: • Oil Red O staining is specific for triacylglycerols • Oil Red O staining is useful to detect oleaginous bacteria • Fast and inexpensive staining to isolate oleaginous bacteria from the environment.

Removal of Azo Dyes from Water Using Natural Luffa cylindrica as a Non-Conventional Adsorbent.

Reducing high concentrations of pollutants such as heavy metals, pesticides, drugs, and dyes from water is an emerging necessity. We evaluated the use of Luffa cylindrica (Lc) as a natural non-conventional adsorbent to remove azo dye mixture (ADM) from water. The capacity of Lc at three different doses (2.5, 5.0, and 10.0 g/L) was evaluated using three concentrations of azo dyes (0.125, 0.250, and 0.500 g/L). The removal percent (R%), maximum adsorption capacity (Qm), isotherm and kinetics adsorption models, and pH influence were evaluated, and Fourier-transform infrared spectroscopy and scanning electron microscopy were performed. The maximum R% was 70.8% for 10.0 g L-1Lc and 0.125 g L-1 ADM. The Qm of Lc was 161.29 mg g-1. Adsorption by Lc obeys a Langmuir isotherm and occurs through the pseudo-second-order kinetic model. Statistical analysis showed that the adsorbent dose, the azo dye concentration, and contact time significantly influenced R% and the adsorption capacity. These findings indicate that Lc could be used as a natural non-conventional adsorbent to reduce ADM in water, and it has a potential application in the pretreatment of wastewaters.

Enhanced degradation of Direct Red 80 dye via Fenton-like process mediated by cobalt ferrite: generated superoxide radicals and singlet oxygen.

Azo dyes, widely used in the textile industry, contribute to effluents with significant organic content. Therefore, the aim of this work was to synthesize cobalt ferrite (CoFe2O4) using the combustion method and assess its efficacy in degrading the azo dye Direct Red 80 (DR80). TEM showed a spherical structure with an average size of 33 ± 12 nm. Selected area electron diffraction and XRD confirmed the presence of characteristic crystalline planes specific to CoFe2O4. The amount of Co and Fe metals were determined by ICP-OES, indicating an n(Fe)/n(Co) ratio of 2.02. FTIR exhibited distinct bands corresponding to Co-O (455 cm-1) and Fe-O (523 cm-1) bonds. Raman spectroscopy detected peaks associated with octahedral and tetrahedral sites. For the first time, the material was applied to degrade DR80 in an aqueous system, with the addition of persulfate. Consistently, within 60 min, these trials achieved nearly 100% removal of DR80, even after the material had undergone five cycles of reuse. The pseudo-second-order model was found to be the most fitting model for the experimental data (k2 = 0.07007 L mg-1 min-1). The results strongly suggest that degradation primarily occurred via superoxide radicals and singlet oxygen. Furthermore, the presence of UV light considerably accelerated the degradation process (k2 = 1.54093 L mg-1 min-1). The material was applied in a synthetic effluent containing various ions, and its performance consistently approached 100% in the photo-Fenton system. Finally, two degradation byproducts were identified through HPLC-MS/MS analysis.

Cost-Effectiveness of Onasemnogene Abeparvovec Compared With Nusinersen and Risdiplam in Patients With Spinal Muscular Atrophy Type 1 in Brazil: Custo-Efetividade do Onasemnogeno Abeparvoveque (AVXS-101) em Comparação ao Nusinersena e Risdiplam em Pacientes com Atrofia Muscular Espinhal Tipo 1 no Brasil.

OBJECTIVES: This study aimed to evaluate the cost-effectiveness of the onasemnogene abeparvovec in relation to nusinersen and risdiplam in the treatment of spinal muscular atrophy type 1 from the perspective of the Brazilian Unified Health System. METHODS: A Markov model was built on a lifetime horizon. Short-term data were obtained from clinical trials of the technologies and from published cohort survival curves (long term). Costs were measured in current 2022 local currency (R$) values and benefits in quality-adjusted life-years (QALYs). Utility values were derived from type 1 spinal muscular atrophy literature, whereas costs related to technologies and maintenance care in each health state were obtained from official sources of reimbursement in Brazil. Deterministic and probabilistic, as well as scenario, sensitivity analyses were performed. RESULTS: Compared with the less costly strategy (nusinersen), the use of onasemnogene abeparvovec resulted in an incremental cost of R$2.468.448,06 ($975 671.169 - purchasing power parity [PPP]) and a 3-QALY increment and incremental cost-effectiveness ratio of R$742.890,92 ($293 632.774 - PPP)/QALY. Risdiplam had an extended dominance from other strategies, resulting in an incremental cost-effectiveness ratio of R$926.586,22 ($366 239.612 - PPP)/QALY compared with nusinersen. Sensitivity analysis showed a significant impact of the follow-up time of the cohort and the cost of acquiring onasemnogene abeparvovec. CONCLUSIONS: Over a lifetime horizon, onasemnogene abeparvovec seems to be a potentially more effective option than nusinersen and risdiplam, albeit with an incremental cost. Such a trade-off should be weighed in efficiency criteria during decision making and outcome monitoring from the perspective of the Brazilian Unified Health System.

Photocatalytic activity of silver nanoparticles@cellulose nanocomposites, from pistachio husk, in the toxic azo commercial dye degradation.

In this work, an over-the-counter commercial dye, containing direct blue 151 in its composition, which is also discarded without any environmental regulation, was efficiency photodegraded using a green chemistry-synthesized nanocomposites type silver nanoparticles (AgNPs) supported on pistachio husk (PH). The green synthesis (GS) of the nanocomposites was carried out using the Anemopsis californica leaf extract (ExAc) as a reducing-stabilizing agent (AgNPs/ExAc-PH), for the first time. The presence of AgNPs on the nanocomposite surface was corroborated by field emission transmission electron microscope (FE-TEM), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The synthesized AgNPs/ExAc-PH has a bimodal size of 24 and 25 nm (4.86 % each) and a 0.72 % of AgNPs on its surface. AgNPs were adhered to the PH surface, through secondary bonds between the Ag and the cellulose of the PH. The optimum conditions, for efficient photocatalytic degradation, were 5 mg of nanocomposite, 3.18 × 10-2 M of NaBH4, natural sunlight, and stirring; this results in a photodegradation efficiency of 100 % almost instantaneously. Furthermore, it was shown that the dye degradation process is primarily due to the photocatalytic degradation of the dye, which occurs almost instantaneously.

Deciphering the origin of the first steps in the degradation of azo dyes: a computational study.

Azo dyes find applications across various sectors including food, pharmaceuticals, cosmetics, printing, and textiles. The contaminating effects of dyes on aquatic environments arise from toxic effects caused by their long-term presence in the environment, buildup in sediments, particularly in aquatic species, degradation of pollutants into mutagenic or mutagenic compounds, and low aerobic biodegradability. Therefore, we theoretically propose the first steps of the degradation of azo dyes based on the interaction of hydroperoxyl radical (•OOH) with the dye. This interaction is studied by the OC and ON mechanisms in three azo dyes: azobenzene (AB), disperse orange 3 (DO3), and disperse red 1 (DR1). Rate constants calculated at several temperatures show a preference for the OC mechanism in all the dyes with lower activation energies than the ON mechanism. The optical properties were calculated and because the dye-•OOH systems are open shell, to verify the validity of the results, a study of the spin contamination of the ground [Formula: see text] and excited states [Formula: see text] was previously performed. Most of the excited states calculated are acceptable as doublet states. The absorption spectra of the dye-•OOH systems show a decrease in the intensity of the bands compared to the isolated dyes and the appearance of a new band of the type π → π* at a longer wavelength in the visible region, achieving up to 868 nm. This demonstrates that the reaction with the •OOH radical could be a good alternative for the degradation of the azo dyes.

New and effective cassava bagasse-modified biochar to adsorb Food Red 17 and Acid Blue 9 dyes in a binary mixture.

A promissory technic for reducing environmental contaminants is the production of biochar from waste reuse and its application for water treatment. This study developed biochar (CWb) and NH4Cl-modified biochar (MCWb) using cassava residues as precursors. CWb and MCWb were characterized and evaluated in removing dyes (Acid Blue 9 and Food Red 17) in a binary system. The adsorbent demonstrated high adsorption capacity at all pH levels studied, showing its versatility regarding this process parameter. The equilibrium of all adsorption experiments was reached in 30 min. The adsorption process conformed to pseudo-first-order kinetics and extended Langmuir isotherm model. The thermodynamic adsorption experiments demonstrated that the adsorption process is physisorption, exhibiting exothermic and spontaneous characteristics. MCWb exhibited highly efficient and selective adsorption behavior towards the anionic dyes, indicating maximum adsorption capacity of 131 and 150 mg g-1 for Food Red 17 and Acid Blue 9, respectively. Besides, MCWb could be reused nine times, maintaining its original adsorption capacity. This study demonstrated an excellent adsorption capability of biochars in removing dyes. In addition, it indicated the recycling of wastes as a precursor of bio composts, a strategy for utilization in water treatment with binary systems. It showed the feasibility of the reuse capacity that indicated that the adsorbent may have many potential applications.

Biodegradation and reduction of toxicity of Azo Trypan Blue dye by Amazonian strains of gasteroid fungi (Basidiomycota).

Amazonian strains of Cyathus spp. and Geastrum spp. were studied for the ability to discolor the trypan blue azo dye and reduce its toxicity. Discoloration of trypan blue dye (0.05%) was evaluated in solid and aqueous medium over different periods. The reduction of dye toxicity after treatment was assessed by seed germination and the development of lettuce seedlings (Lactuca sativa L.) and toxicity test in Artemia salina (L.) larvae. All evaluated strains showed the potential to reduce the color intensity of trypan blue dye. Cyathus strains reached 96% discoloration, and C. albinus and C. limbatus also reduced dye toxicity. Geastrum strains showed a high efficiency degree in color reduction, reaching 98% discoloration, however, the by-products generated during the process presented toxicity and require further investigation. For the first time, Amazonian strains of gasteroid fungi degrading trypan blue are reported, some even reducing its toxicity. Thus, making them promising sources of enzymes of interest to bioremediation scenarios involving synthetic dyes.

Changing Despicable Me: Potential replacement of azo dye yellow tartrazine for pequi carotenoids employing ionic liquids as high-performance extractors.

Color is a crucial sensory attribute that guides consumer expectations. A high-performance pequi carotenoid extraction process was developed using ionic liquid-based ethanolic solutions and a factorial design strategy to search for a potential substitute for the artificial azo dye yellow tartrazine. All-trans-antheraxanthin was identified with HPLC-PAD-MSn for the first time in pequi samples. [BMIM][BF4] was the most efficient ionic liquid, and the maximization process condition was the solid-liquid ratio R(S/L) of 1:3, the co-solvent ratio R(IL/E) of 1:1 ([BMIM][BF4]: ethanol), and three cycles of extraction with 300 s each and yielded 107.90 µg carotenoids/g of dry matter. The ionic liquid-ethanolic solution recyclability was accomplished by freezing and precipitating with an average recovery of 79 %. In CIELAB parameters, pequi carotenoid extracted with [BMIM][BF4] was brighter and yellower than the artificial azo dye yellow tartrazine. A color change of 11.08 and a hue* difference of 1.26° were obtained. Furthermore, carotenoids extracted with [BMIM][BF4] showed antioxidant activity of 35.84 µmol of α-tocopherol. These findings suggest the potential of employing the pequi carotenoids to replace the artificial azo dye yellow tartrazine in foods for improved functional properties.

Harnessing Efficient ROS Generation in Carbon Dots Derived from Methyl Red for Antimicrobial Photodynamic Therapy.

The emergence of drug-resistant pathogenic microorganisms has become a public health concern, with demand for strategies to suppress their proliferation in healthcare facilities. The present study investigates the physicochemical and antimicrobial properties of carbon dots (CD-MR) derived from the methyl red azo dye. The morphological and structural analyses reveal that such carbon dots present a significant fraction of graphitic nitrogen in their structures, providing a wide emission range. Based on their low cytotoxicity against mammalian cells and tunable photoluminescence, these carbon dots are applied to bioimaging in vitro living cells. The possibility of using CD-MR to generate reactive oxygen species (ROS) is also analyzed, and a high singlet oxygen quantum efficiency is verified. Moreover, the antimicrobial activity of CD-MR is analyzed against pathogenic microorganisms Staphylococcus aureus, Candida albicans, and Cryptococcus neoformans. Kirby-Bauer susceptibility tests show that carbon dots synthesized from methyl red possess antimicrobial activity upon photoexcitation at 532 nm. The growth inhibition of C. neoformans from CD-MR photosensitization is investigated. Our results show that N-doped carbon dots synthesized from methyl red efficiently generate ROS and possess a strong antimicrobial activity against healthcare-relevant pathogens.

Assessment of urinary aromatic amines in Brazilian pregnant women and association with DNA damage: Influence of genetic diversity, lifestyle, and environmental and socioeconomic factors.

Aromatic amines (AAs) are polar organic chemicals with a wide environmental distribution originating from various sources, such as tobacco smoke, diesel exhaust, and dermal absorption from textile products with azo dyes. The toxicity profile of AAs is directly related to the amino group's metabolic activation and the generation of the reactive intermediate, forming DNA adducts and potential carcinogenicity. Urinary levels of 8-hydroxy-2'-deoxyguanosine (8OHdG) are an important biomarker of DNA damage. Since AAs have been shown to cross the placental barrier, being a risk factor for adverse birth outcomes, prenatal exposure is a great public health concern. The present study aimed to measure the urinary levels of 58 AAs in Brazilian pregnant women (n = 300) and investigated the impact of this exposure on DNA damage by quantifying 8OHdG levels. The influence of tobacco smoke exposure and dermal absorption of AAs by clothes on urinary levels was also assessed. The results showed a 100% detection rate for eight AAs, two of them regulated by the European Union (2,6-dimethylaniline and 2,4-diaminotolune). Hundreds of AAs may be derived from aniline, which here showed a median of 1.38 ng/mL. Aniline also correlated positively with 2,6-dimethylaniline, p-aminophenol, and other AAs, suggesting exposure to multiple sources. The present findings suggest that both tobacco smoke and dermal contact with clothes containing azo dyes are potential sources that might strongly influence urinary levels of AAs in Brazilian pregnant women. A multiple regression linear model (R2 = 0.772) suggested that some regulated AAs (i.e., 2-naphthylamine and 4-aminobiphenyl), nicotine, smoke habit, age, and Brazilian region could induce DNA damage occurrence, increasing the levels of 8OHdG. Given the limited available data on human exposure to carcinogenic AAs, as well as the lack of toxicological information on those non-regulated, further studies focused on measuring their levels in human fluids and the potential exposure sources are clearly essential.

Dietary exposure to food azo-colours in a sample of pre-school children from Southern Brazil.

The dietary exposure of six food azo-colours was assessed in a sample of pre-schoolers from Guaratuba-Paraná, Brazil. Consumption data of 323 children aged 2 to 5 years was collected through 3-day food records. Dietary exposure, is expressed by milligrams of food colour by kilogram of body weight per day, as compared to the Acceptable Daily Intake (ADI). Three exposure scenarios were developed to account for uncertainties around consumption estimates. Intakes of Amaranth (INS 123) described in means, 50th and 95th percentiles exceeded ADI levels in the two most conservative scenarios, with the highest percentiles exceeding about four times the ADI. High intakes of Sunset Yellow FCF (INS 110) were also observed, of up to 85% of the ADI in the worst-case scenario. Findings suggest high exposure levels to azo-dyes in the survey population, with children likely exceeding the ADI for Amaranth (INS 123) and concerns for Sunset Yellow FCF (INS 110). Major food contributors were beverages (juice powders and soft drinks), dairy and sweets. Further studies on dietary exposure assessment are needed at the national level. The authors highlight the need of controlling the use of such additives through national policies that are aligned with the consumption patterns observed in the country.

Biosorption of methylene blue by residue from Lentinus crinitus mushroom cultivation.

Conventional textile effluent treatments cannot remove methylene blue, a mutagenic azo dye, and an endocrine disruptor, that remains in the drinking water after conventional water treatment. However, the spent substrate from Lentinus crinitus mushroom cultivation, a waste, could be an attractive alternative to remove persistent azo dyes in water. The objective of this study was to assess the methylene blue biosorption by spent substrate from L. crinitus mushroom cultivation. The spent substrate obtained after mushroom cultivation had been characterized by the point of zero charge, functional groups, thermogravimetric analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. Moreover, the spent substrate biosorption capacity was determined in function of pH, time, and temperature. The spent substrate had a point of zero charge value of 4.3 and biosorbed 99% of methylene blue in pH from 3 to 9, with the highest biosorption in the kinetic assay of 15.92 mg g- 1, and in the isothermal assay of 120.31 mg g- 1. Biosorption reached equilibrium at 40 min after mixing and best fitted the pseudo-second-order model. Freundlich model best fitted the isothermal parameters and each 100 g spent substrate biosorbed 12 g dye in an aqueous solution. The spent substrate of L. crinitus cultivation is an effective biosorbent of methylene blue and an alternative to removing this dye from water, adding value to the mushroom production chain, and supporting the circular economy.

Exploring visible light enhancement for sensing: an azo-dye decorated gold nanoantenna monitored with a smartphone app.

Optical sensors can be used to detect a variety of substances ranging from diagnostics on biological samples to the detection of hazardous substances. This type of sensor can be a valuable alternative to more complex analytical techniques, being fast and requiring little to no sample preparation at the expense of the reusability of the device. Here, we show the construction of a colorimetric nanoantenna sensor using gold nanoparticles (AuNPs) embedded in poly(vinyl alcohol) (PVA) and decorated with the methyl orange (MO) azo dye (AuNP@PVA@MO) that is potentially reusable. As a proof of concept, we apply this sensor to detect H2O2 both visually and using a smartphone-based app for colorimetric measurements. Furthermore, through chemometric modeling of the app data, we can reach a detection limit of 0.0058% (1.70 mmolL-1) of H2O2 while being able to visually detect changes on the sensor. Our results reinforce the combination of nanoantenna sensors with chemometric tools as guidelines for sensor design. Finally, this approach can lead to novel sensors allowing for the visual detection of analytes in complex samples and their quantification using colorimetry.

Screening of regulated aromatic amines in clothing marketed in Brazil and Spain: Assessment of human health risks.

Azo dyes used in textile products contain aromatic amines (AAs), which may be released into the environment after skin bacteria cleavage the azo bond. In Europe, 22 carcinogenic AAs are regulated. Unfortunately, no information is available in many non-European countries, including Brazil. This study aimed to determine the concentrations of 20 regulated AAs in clothes marketed in Brazil and Spain. Generally, higher levels of regulated AAs were found in samples sold in Brazil than in Spain, which is linked to the lack of regulation. Sixteen AAs showed concentrations above 5 mg/kg in samples commercialized in Brazil, while 11 exceeded that threshold in Spain. Regulated AAs with levels above 5 mg/kg were more found in synthetic clothes of pink color. Concentrations in clothing were also used to evaluate the dermal exposure to AAs in 3 vulnerable population groups. The highest exposure corresponded to 2,4-diaminoanisole for toddlers in Brazil and 4,4-oxydianiline for newborns in Spain. Non-cancer risks associated with exposure to 4,4-benzidine by Brazilian toddlers was 14.5 (above the threshold). On the other hand, 3,3-dichlorobenzidine was associated with potential cancer risks for newborns and toddlers in Brazil. Given this topic's importance, we recommend conducting continuous studies to determine the co-occurrence of carcinogenic substances.

Textile azo dyes discolouration using spent mushroom substrate: enzymatic degradation and adsorption mechanisms.

This study evaluated the adsorption and enzymatic degradation of azo dyes when using SMS. The laccase present in the SMS was characterised, and the maximum activity was obtained at pH 2, a temperature of 45°C, a Michaelis-Menten constant (Km) of 0.264 mM, and a maximum reaction rate (Vmax) of 117.95 µmol L-1 min-1. The presence of NaCl at 5 mM inhibited enzyme activity while no inhibition was observed by Na2SO4, typically found in textile wastewater. The maximum dye adsorption (57.22%) was achieved at pH 8.0, 25°C, and 100 g L-1 of SMS while the maximum enzymatic degradation (14.18%) was obtained under the same conditions, except at pH 4.0. The enzymes laccase, lignin peroxidase, and manganese peroxidase trapped in the SMS resulted in higher dye discolouration when compared to that extracted with aqueous solution, meaning that SMS has strong adsorption capacity and is a natural immobilisation matrix, which improves the enzymatic degradation of the dyes. Thus, SMS can be used in the treatment of textile effluents for dye removal by simultaneous mechanisms of adsorption and enzymatic degradation, with reduction of environmental impacts for SMS disposal and reduction of the costs associated with commercial enzymes and adsorbents.