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.

Purification and characterization of lignin peroxidase from white-rot fungi Pleurotus pulmonarius CPG6 and its application in decolorization of synthetic textile dyes

From the biotechnological point of view, enzymes are powerful tools that help sustain a clean environment in several ways. The enzymatic biodegradation of synthetic dyes is a promising goal since it reduces pollution caused by textile dyeing factory wastewater. Lignin peroxidase (EC 1.11.1.14, LiP) has high redox potential; thus, it is great for application in various industrial fields (e.g., paper- waste treatment and textile dyeing wastewater treatment). In the present study, a LiP from an isolated strain Pleurotus pulmonarius CPG6 (PpuLiP) was successfully purified with a specific activity of 6.59 U mg ^-1. The enzyme was purified by using three-step column chromatography procedures including DEAE, Sephadex G-75, and HiTrap^TM Q FF columns with 17.8-fold purity. The enzyme with a molecular weight of 40 kDa exhibited enhanced pH stability in the acidic range. The activity retention was over 75% at a pH of 3.0 for more than 6 hours. Purified PpuLiP was able to oxidize a variety of substrates including veratryl alcohol, 2,4-DCP, n propanol, and guaiacol. The effect of metal ions on PpuLiP activity was analyzed. The study will provide a ground to decolorize dyes from various groups of PpuLiP. Purified PpuLiP could decolorize 35% Acid blue 25 (AB25), 50% Acid red 129 (AB129), 72% Acid blue 62 (NY3), 85% Acid blue 113 (AB113), 55% Remazol Brilliant blue R (RBBR), and 100% Reactive red 120 (RR120) for 12 hours. Most of the dyes were decolorized, but the heat-denatured enzyme used as negative control obviously did not decolorize the tested dyes. These results indicate that the PpuLiP has potential application in enzyme-based decolorization of synthetic dyes. Keywords: Decolorization; lignin peroxidase; Pleurotus pulmonarius; textile dyes.

The prevalence and relevance of patch testing with textile dyes

BACKGROUND

Textile dye mix (TDM) is included in the European baseline series (EBS), but it is unknown if TDM identifies all patients with a textile dye allergy.

OBJECTIVES

To assess the added value of performing patch testing with individual textile dyes in addition to TDM.

METHODS

Two hundred and nine patients suspected to have a contact allergy to textile dyes were patch tested between January 2015 and December 2021 with the EBS, as well as an individual textile dye test series containing textile dyes part of TDM (TDM-dyes) and outside the scope of TDM (non-TDM dyes).

RESULTS

Fifty-four patients (25.8%) tested positive for TDM or an individual textile dye. Disperse Orange 3 (9.6%) followed by Disperse Blue 106 (4.8%) were the most common individual textile dyes causing a positive patch test reaction. Of the 54 dye positive patients, 28 (51.9%) had a clinically relevant reaction. No clinically relevant reactions were seen in patients that solely tested positive for non-TDM dyes.

CONCLUSIONS

It is beneficial to test individual textile dyes in addition to TDM in patients suspected of having a textile dye allergy. Otherwise, 46.3% of the dye positive patients and 35.7% of the patients with a clinically relevant reaction would have been missed.

Removal Efficiency of Insoluble β-Cyclodextrin Polymer from Water-Soluble Carcinogenic Direct Azo Dyes

A batch system was applied to study the adsorption of three dyes (methyl violet, eriochrom black T and helianthin) from aqueous solution onto β-cyclodextrin polymer, synthesized by using citric acid as a cross linking agent. This polymer lets to adsorb only methyl violet for this effect, several operator variables was checked only with this kind of dye, the removal efficiently increases with increase in adsorbent amount; elevation of temperature lets also to improve the dye adsorption; ionic strength has not effect on dye adsorption process, for the pH we have remarked a slight decrease in removal efficiently with increasing of pH values. Equilibrium study was investigated by applying three models (Langumir, Frendlich and Temkin), results show that Langumir isotherm is the appropriate model. FTIR spectra show the complex inclusion formation which dominates the adsorption mechanism, confirmed by the absence of characteristic peaks of methyl violet in ß-cyclodextrin after adsorption.

Evaluation of dye decolorization using anaerobic granular sludge from an expanded granular sludge bed based on spectrometric and microbiome analyses

The decolorization of 11 dyes by granular sludge from an anaerobic expanded granular sludge bed (EGSB) reactor was evaluated. Biological decolorization of Reactive Red 21, 23, and 180, and Reactive Yellow 15, 17, and 23 in model textile wastewater was observed for the first time after a 7-day incubation (over 94% decolorization). According to the sequencing analysis of 16S rRNA gene amplicons from EGSB granular sludge, the operational taxonomic unit related to Paludibacter propionicigenes showed the highest increase in relative abundance ratios in the presence of dyes (7.12 times on average over 11 dyes) compared to those without dyes.

Labeling Microplastics with Fluorescent Dyes for Detection, Recovery, and Degradation Experiments

Staining microplastics (MPs) for fluorescence detection has been widely applied in MP analyses. However, there is a lack of standardized staining procedures and conditions, with different researchers using different dye concentrations, solvents, incubation times, and staining temperatures. Moreover, with the limited types and morphologies of commercially available MPs, a simple and optimized approach to making fluorescent MPs is needed. In this study, 4 different textile dyes, along with Nile red dye for comparison, are used to stain 17 different polymers under various conditions to optimize the staining procedure. The MPs included both virgin and naturally weathered polymers with different sizes and shapes (e.g., fragments, fibers, foams, pellets, beads). We show that the strongest fluorescence intensity occurred with aqueous staining at 70 °C for 3 h with a dye concentration of 5 mg/mL, 55 mg/mL, and 2 µg/mL for iDye dyes, Rit dyes, and Nile red, respectively. Red fluorescent signals are stronger and thus preferred over green ones. The staining procedure did not significantly alter the surface, mass, and chemical characteristics of the particles, based on FTIR and stereomicroscopy. Stained MPs were spiked into freshwater, saltwater, a sediment slurry, and wastewater-activated sludge; even after several days, the recovered particles are still strongly fluoresced. The approach described herein for producing customized fluorescent MPs and quantifying MPs in laboratory-controlled experiments is both straightforward and simple.

Biodegradation of Azo Dye Methyl Red by Pseudomonas aeruginosa: Optimization of Process Conditions

Water pollution due to textile dyes is a serious threat to every life form. Bacteria can degrade and detoxify toxic dyes present in textile effluents and wastewater. The present study aimed to evaluate the degradation potential of eleven bacterial strains for azo dye methyl red. The optimum degradation efficiency was obtained using P. aeruginosa. It was found from initial screening results that P. aeruginosa is the most potent strain with 81.49% degradation activity and hence it was subsequently used in other degradation experiments. To optimize the degradation conditions, a number of experiments were conducted where only one variable was varied at a time and where maximum degradation was observed at 20 ppm dye concentration, 1666.67 mg/L glucose concentration, 666.66 mg/L sodium chloride concentration, pH 9, temperature 40 °C, 1000 mg/L urea concentration, 3 days incubation period, and 66.66 mg/L hydroquinone (redox mediator). The interactive effect of pH, incubation time, temperature, and dye concentration in a second-order quadratic optimization of process conditions was found to further enhance the biodegradation efficiency of P. aeruginosa by 88.37%. The metabolites of the aliquot mixture of the optimized conditions were analyzed using Fourier transform infrared (FTIR), GC-MS, proton, and carbon 13 Nuclear Magnetic Resonance (NMR) spectroscopic techniques. FTIR results confirmed the reduction of the azo bond of methyl red. The Gas Chromatography-Mass Spectrometry (GC-MS) results revealed that the degraded dye contains benzoic acid and o-xylene as the predominant constituents. Even benzoic acid was isolated from the silica gel column and identified by ¹H and ¹³C NMR spectroscopy. These results indicated that P. aeruginosa can be utilized as an efficient strain for the detoxification and remediation of industrial wastewater containing methyl red and other azo dyes.

UV-Based Advanced Oxidation Processes of Remazol Brilliant Blue R Dye Catalyzed by Carbon Dots

UV-based advanced oxidation processes (AOPs) (UV/H₂O₂ and UV/S₂O₈^2-) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 °C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO₂ doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H₂O₂, UV/S₂O₈^2-, and UV/TiO₂), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H₂O₂/TIP-CD-0.0330 min^-1 and UV/1.02 mM S₂O₈^2-/TIP-CD-0.0345 min^-1.

Application of Capillary Electromigration Methods in the Analysis of Textile Dyes-Review

Fiber traces are one of (micro)traces that can be found at a crime scene. They are easily transferable and, like other forms of evidence, can provide a link between a suspect and a victim. The main purpose of this review is to present methods developed to examine textile dyes extracted for forensic purposes using different capillary electromigration methods (CEMs). Scientific papers, mainly from the 20th century, provide reliable methods for the separation of water-soluble dyes. However, dyes insoluble in aqueous solutions have been and still are a challenge. Another problem is the sensitivity of the developed methods, which is, in most cases, insufficient for forensic examination of dyes extracted from a single fiber preserved at the crime scene. Although the methodologies already developed and presented in this review have the potential to be applied in a comparative analysis of textile dye traces, there seems to be a lot of work to be conducted. Some ideas on how to resolve these problems are presented and discussed in the article.

Copper(II)-Doped Carbon Dots as Catalyst for Ozone Degradation of Textile Dyes

A catalytic ozonation advanced oxidation process (AOP) with a copper(II)-doped carbon dot as catalyst, Cu-CD (using L-cysteine and polyethylene glycol (PEG) as precursors and passivation agents), was developed for textile wastewater treatment (T = 25 °C and pH = 7). Four dyes were analyzed—Methyl Orange (MO), Orange II sodium salt (O-II), Reactive Black 5 (RB-5) and Remazol Brilliant Blue R (RBB-R), as well as a real effluent from the dying and printing industry. The Cu-CD, with marked catalytic ozonation properties, was successfully synthesized by one-pot hydrothermal procedure with a size of 4.0 nm, a charge of −3.7 mV and a fluorescent quantum yield of 31%. The discoloration of the aqueous dye solutions followed an apparent first-order kinetics with the following rate constants (kap in min−1): MO, 0.210; O-II, 0.133; RB-5, 0.177; RBB-R, 0.086. In the presence of Cu-CD, the following apparent first-order rate constants were obtained (kapc in min−1) with the corresponding increase in the rate constant without catalyst (%Inc): MO, 1.184 (464%); O-II, 1.002 (653%); RB-5, 0.709 (301%); RBB-R, 0.230 (167%). The presence of sodium chloride (at a concentration of 50 g/L) resulted in a marked increase of the discoloration rate of the dye solution due to generation of other radicals, such as chlorine and chlorine oxide, resulting from the reaction of ozone and chloride. Taking into consideration that the real textile effluent under research has a high carbonate concentration (>356 mg/L), which inhibits ozone decomposition, the discoloration first-order rate constants without and with Cu-CD (kap = 0.0097 min−1 and kapc = 0.012 min−1 (%Inc = 24%), respectively) were relatively small. Apparently, the Cu-CD, the surface of which is covered by a soft and highly hydrated caramelized PEG coating, accelerates the ozone decomposition and dye adsorption, increasing its degradation.

Decolorization of reactive blue 13 by Sporotrichum sp. and cytotoxicity of biotreated dye solution

Wastewater from the textile industry contaminated with azo dyes affects the environment negatively, causes pollution, and threatens environmental balance. Among various methods for wastewater treatment, bioremediation emerges as an environmentally friendly, economical, and sustainable solution. In this study, white-rot fungus Sporotrichum sp. was employed to decolorize reactive blue 13 (RB13). The long-term decolorization capacity of the fungus was investigated by a sequential batch experiment under optimized conditions. The fungus showed high decolorization efficiency upon repeating usage, and its decolorization efficiency decreased from 97.4% to 87.09% after transferring to a freshly prepared medium seven times. The MTT (3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide) assay) method using Chinese Hamster Lung V79 379A was performed to assess the cytotoxicity of treated water samples. This study revealed that Sporotrichum sp. has short-term enzymatic and long-term biosorption capacity on reactive blue 13 and the decolorization potential of the alive and dead cells is impressively high. PRACTITIONER POINTS: White-rot fungus Sporotrichum sp. is able to decolorize sulfonated azo-dye reactive blue 13 upon sequential incubation in freshly prepared dye solution. The decolorization mechanism of the fungus is estimated to be bioadsorption. Sporotrichum sp. can be considered for long-term usage and immobilization applications.

Antimicrobial and dye degradation application of fungi-assisted silver nanoparticles and utilization of fungal retentate biomass for dye removal

The present study utilized Aspergillus spp. for the synthesis of silver nanoparticles (AgNPs); the developed AgNPs were categorized using analytical techniques, that is, ultraviolet-visible (UV-vis) spectrophotometer, Zeta-potential, dynamic light scattering (DLS), and transmission electron microscopy (TEM). A sharp peak of 463 nm highlighted the synthesis of AgNPs; further Zeta-potential of -16 mV indicates stability of synthesized AgNPs. The TEM micrograph showed spherical and hexagonal shapes of synthesized AgNPs of 6-25 nm. The photocatalytic activity of fungal-mediated AgNPs was evaluated for degradation of reactive yellow dye in the concentration range of 20-100 mg L^-1 . The results showed efficient degradation of dye using AgNPs in short span of time. For antibacterial activity, synthesized AgNPs, antibiotic, and AgNPs + antibiotic were tested. As per results, the zone of inhibition (ZOI) of AgNPs showed the values of 13 and 10 mm for Escherichia coli and Staphylococcus aureus, respectively. Further, the ZOI of penicillin highlighted the values of 18 and 17 mm for E. coli and S. aureus, respectively. When AgNPs and penicillin were used in combination, a clear synergistic effect was observed; the ZOI showed 0.49- and 0.36-fold increase in area against E. coli and S. aureus, respectively, in comparison with penicillin or AgNPs alone. Further, the leftover biomass (retentate biomass) was used to decolorize the reactive yellow dye at different initial concentration ranging from 20 to 100 mg L^-1 . It was observed that 1 g L^-1 retentate biomass (B_R ) can effectively remove 82%-100% dye at 20 and 100 mg L^-1 initial dye concentration. Results also indicated that with increase in initial reactive dye concentration from 20 to 100 mg L^-1 , the decolorization capacity of retentate biomass (B_R ) (at 0.2 g L^-1 ) decreased from 79.2% to 32.3%. However, the use of AgNPs synthesized leftover fungal biomass can be a good option for up taking the additional dyes/contaminants, and also as leftover biomass can be utilized effectively, it can prove to be an excellent approach for environment safety. As the literature studies did not mentioned the further use of retentate biomass, the present study provides an excellent approach for further research on this aspect. PRACTITIONER POINTS: Synthesis of AgNPs from Aspergillus spp. and characterized with the help of a U.V-vis spectrophotometer, a zeta potential, DLS and TEM. The developed AgNPs were used for antibacterial and dye degradation activity. The left over (retentate) fungal biomass was used further for additional dye degradation activity.

Treatment of textile matrices using Fenton processes: influence of operational parameters on degradation kinetics, ecotoxicity evaluation and application in real wastewater

Since conventional processes for treating textile effluents have limitations, this work aimed to investigate the application of advanced oxidation technology in this type of matrix. Initially, for a textile dyes mixture in solution, the photo-Fenton/sunlight process proved to be the most efficient among other systems tested. During the tests it was found that the degradation kinetics depends of the pH and catalyst and oxidant concentrations. After 60 min under optimized conditions, the color was reduced by 98.19%, with 92.52% organic matter conversion. Ecotoxicity tests with the Lactuca Sativa vegetable indicated that the dyes were not totally oxidized to inert compounds, although the treated solution did not cause a significant toxic effect for this species. In the second stage of the research, the photodegradation in real samples of textile wastewater was evaluated. The efficiency of the photo-Fenton/sunlight process was lower than that obtained for the dyes solution, a fact attributed to the greater complexity of the real matrix. However, the data also indicated that the combination of coagulation/flocculation and advanced oxidation processes is the most suitable methodology to reduce the fraction of biodegradable compounds. In summary, research has revealed that photocatalytic degradation of dyes through advanced oxidation is an efficient treatment.

Content of Carotenoids, Violaxanthin and Neoxanthin in Leaves of Triticum aestivum Exposed to Persistent Environmental Pollutants

Persistent pollutants such as pharmaceuticals, pesticides, musk fragrances, and dyes are frequently detected in different environmental compartments and negatively impact the environment and humans. Understanding the impacts of diffuse environmental pollutants on plants is still limited, especially at realistic environmental concentrations of contaminants. We studied the effects of key representatives of two major classes of environmental pollutants (nine different antibiotics and six different textile dyes) on the leaf carotenoid (violaxanthin and neoxanthin) content in wheat (Triticum aestivum L.) using different pollutant concentrations and application times. The wheat plants were watered with solutions of selected environmental pollutants in two different concentrations of 0.5 mg L⁻¹ and 1.5 mg L⁻¹ for one week (0.5 L) and two weeks (1 L). Both categories of pollutants selected for this study negatively influenced the content of violaxanthin and neoxanthin, whereas the textile dyes represented more severe stress to the wheat plants. The results demonstrate that chronic exposure to common diffusively spread environmental contaminants constitutes significant stress to the plants.

Magnetic Nanoparticles of Zinc/Calcium Ferrite Decorated with Silver for Photodegradation of Dyes

Magnetic nanoparticles of zinc/calcium ferrite and decorated with silver were prepared by coprecipitation method. The obtained nanoparticles were characterized by UV/Visible absorption, XRD, TEM and SQUID. The mixed zinc/calcium ferrites exhibit an optical band gap of 1.78 eV. HR-TEM imaging showed rectangular nanoplate shapes with sizes of 10 ± 3 nm and aspect ratio mainly between 1 and 1.5. Magnetic measurements indicated a superparamagnetic behavior. XRD diffractograms allowed a size estimation of 4 nm, which was associated with the nanoplate thickness. The silver-decorated zinc/calcium ferrite nanoparticles were successfully employed in the photodegradation of a model dye (Rhodamine B) and industrial textile dyes (CI Reactive Red 195, CI Reactive Blue 250 and CI Reactive Yellow 145). The nanosystems developed exhibited promising results for industrial application in effluent photoremediation using visible light, with the possibility of magnetic recovery.

Amine Modification of Silica Aerogels/Xerogels for Removal of Relevant Environmental Pollutants

Serious environmental and health problems arise from the everyday release of industrial wastewater effluents. A wide range of pollutants, such as volatile organic compounds, heavy metals or textile dyes, may be efficiently removed by silica materials advanced solutions such as aerogels. This option is related to their exceptional characteristics that favors the adsorption of different contaminants. The aerogels performance can be selectively tuned by an appropriate chemical or physical modification of the aerogel's surface. Therefore, the introduction of amine groups enhances the affinity between different organic and inorganic contaminants and the silica aerogels. In this work, different case studies are reported to investigate and better understand the role of these functional groups in the adsorption process, since the properties of the synthesized aerogels were significantly affected, regarding their microstructure and surface area. In general, an improvement of the removal efficiency after functionalization of aerogels with amine groups was found, with removal efficiencies higher than 90% for lead and Rubi Levafix CA. To explain the adsorption mechanism, both Langmuir and Freundlich models were applied; chemisorption is most likely the sorption type taking place in the studied cases.

Contact sensitivity to textile dyes in patients with pigmented purpuric dermatosis

Purpose: The aetiology of pigmented purpuric dermatoses is unclear. Recent studies speculate about contact sensitivity to play a role in the aetiology of the disease. In most patients, the lesions begin and stay limited on the lower extremities as textile products are in tight contact with the skin. Also, textile dyes can cause contact dermatitis of purpuric type. This study was conducted in order to understand whether the contact sensitivity plays a critical role in the aetiology of pigmented purpuric dermatoses. Materials and methods: Patients with diagnosis of pigmented purpuric dermatoses were included in the study. Patch tests were applied at the back of all patients with textile series (Chemotechnique Diagnostics TF-1000) which have 33 allergens containing textile dyes, material and protectors by IQ Ultra Chamber. Test sites were evaluated at 48, 72, 96. h and on the 7th day according to the criteria of the International Contact Dermatitis Research Group. The evaluation results were recorded in patient files and the results were statistically compared. Results: Eighteen males (60%) and 12 females (40%), a total of 30 patients were included in the study. Schamberg disease in 23 patients (76.7%), lichen aureus in 5 patients (16.7%) and Majocchi disease in 2 patients (6.7%) were described out of total 30 patients. No contact sensitivity was detected in any of the patients. Conclusion: Contact sensitivity to textile dyes was not found as an etiologic factor in our study group.

Chemical Modification and Performance Evaluation of an Agro-Waste for Column Mode Removal of Textile Dyes

The performance of a newly designed column bed device packed with chemically modified agro-waste (sugarcane bagasse) is evaluated for efficient removal of two textile dyes, Optilan yellow and Lanasyn brown and textile industry dye effluent. The parameters used for performance evaluation are removal efficiency (R%), adsorption capacity (q), and breakthrough (C e/C 0). The column exhibits >90% removal of both the dyes and >80% removal of textile industry dye effluent. The experimental data are fitted to three models, viz., Thomas, Adams-Bohart, and Yoon-Nelson for understanding the kinetic behavior of adsorption. The results reveal that the Yoon-Nelson model is the best-fitted model for both the dyes with R 2 values 0.995 and 0.905 for Optilan yellow and Lanasyn brown, respectively. However, Thomas and Yoon-Nelson fit the best for textile industry effluent. Overall, this investigation provides baseline information about the column mode removal of textile dyes using the agro-waste material as an adsorbent. The Fourier transform infrared spectroscopy spectra show the characteristic vibrational mode of C-H stretching of hydroxyl group around 2800-3000 cm-1. The change in the vibrational pattern is evident after alginic acid treatment, indicating delignification of the bagasse after treatment.

Decolorization of textile dyes in an air-lift bioreactor inoculated with Bjerkandera adusta OBR105

A new decolorizing white-rot fungus, OBR105, was isolated from Mount Odae in South Korea and identified by the morphological characterization of its fruit body and spores and partial 18s rDNA sequences. The ligninolytic enzyme activity of OBR105 was studied to characterize their decolorizing mechanism using a spectrophotometric enzyme assay. For the evaluation of the decolorization capacity of OBR105, the isolate was incubated in an erlenmeyer flask and in an airlifte bioreator with potato dextrose broth (PDB) medium supplemented with each dye. In addition, the decolorization efficiency of real textile wastewater was evaluated in an airlift bioreactor inoculated with the isolate. The isolate was identified as Bjerkandera adusta and had ligninolytic enzymes such as laccase, lignin peroxidase (LiP), and Mn-dependent peroxidase (MnP). Its LiP activity was higher than its MnP and laccase activities. B. adusta OBR105 successfully decolorized reactive dyes (red 120, blue 4, orange 16, and black 5) and acid dyes (red 114, blue 62, orange 7, and black 172). B. adusta OBR105 decolorized 91-99% of 200 mg L^-1 of each dye (except acid orange 7) within 3 days in a PDB medium at 28°C, pH 5, and 150 rpm. This fungus decolorized only 45% of 200 mg L^-1 acid orange 7 (single azo-type dye) within 3 days, and the decolorization efficiency did not increase by prolonging the cultivation time. In the air-lift bioreactor, B. adusta OBR105 displayed a high decolorization capacity, greater than 90%, for 3 acid dyes (red 114, blue 62, and black 172) and 1 reactive dye (blue 4) within 10-15 h of treatment. B. adusta OBR105 could decolorize real textile wastewater in the air-lift bioreactor. This result suggests that an air-lift reactor employing B. adusta OBR105 is a promising bioreactor for the treatment of dye wastewater.

Decolorization of acid, disperse and reactive dyes by Trametes versicolor CBR43

The mycoremediation has been considered as a promising method for decolorizing dye wastewater. To explore new bioresource for mycoremediation, a new white-rot fungus that could decolorize various dyes commonly used in textile industries was isolated, and its ligninolytic enzyme activity and decolorization capacity were characterized. The isolated CBR43 was identified as Trametes versicolor based on the morphological properties of its fruit body and spores, as well as through partial 18S rDNA gene sequences. Isolated CBR43 displayed high activities of laccase and Mn-dependent peroxidase, whereas its lignin peroxidase activity was relatively low. These ligninolytic enzyme activities in potato dextrose broth (PDB) medium were enhanced by the addition of yeast extract (1-10 g L^-1). In particular, lignin peroxidase activity was increased more than 5 times in the PDB medium amended with 10 g L^-1 of yeast extract. The CBR43 decolorized more than 90% of 200 mg L^-1 acid dyes (red 114, blue 62 and black 172) and reactive dyes (red 120, blue 4, orange 16 and black 5) within 6 days in the PDB medium. CBR43 decolorized 67% of 200 mg L^-1 acid orange 7 within 9 days. The decolorization efficiencies for disperse dyes (red 1, orange 3 and black 1) were 51-80% within 9 days. The CBR43 could effectively decolorize high concentrations of acid blue 62 and acid black 172 (500-700 mg L^-1). The maximum dye decolorization rate was obtained at 28°C, pH 5, and 150 rpm in the PDB medium. T. versicolor CBR43 had high laccase and Mn-dependent peroxidase activities, and could decolorize a wide variety of dyes such as acid, disperse and reactive textile dyes. This fungus had decolorizing activities of azo-type dyes as well as anthraquinone-type dyes. T. versicolor CBR43 is one of promising bioresources for the decolorization of textile wastewater including various dyes.

Immobilized Lignin Peroxidase-Like Metalloporphyrins as Reusable Catalysts in Oxidative Bleaching of Industrial Dyes

Synthetic and bioinspired metalloporphyrins are a class of redox-active catalysts able to emulate several enzymes such as cytochromes P450, ligninolytic peroxidases, and peroxygenases. Their ability to perform oxidation and degradation of recalcitrant compounds, including aliphatic hydrocarbons, phenolic and non-phenolic aromatic compounds, sulfides, and nitroso-compounds, has been deeply investigated. Such a broad substrate specificity has suggested their use also in the bleaching of textile plant wastewaters. In fact, industrial dyes belong to very different chemical classes, being their effective and inexpensive oxidation an important challenge from both economic and environmental perspective. Accordingly, we review here the most widespread synthetic metalloporphyrins, and the most promising formulations for large-scale applications. In particular, we focus on the most convenient approaches for immobilization to conceive economical affordable processes. Then, the molecular routes of catalysis and the reported substrate specificity on the treatment of the most diffused textile dyes are encompassed, including the use of redox mediators and the comparison with the most common biological and enzymatic alternative, in order to depict an updated picture of a very promising field for large-scale applications.

Lymphomatoid contact dermatitis associated with textile dye at an unusual location

Lymphomatoid contact dermatitis (LCD) is a rare variant of noneczematous allergic contact dermatitis, which can mimick parapsoriasis or early-stage mycosis fungoides with its atypical clinical and histopathological manifestation. Many different haptens have been reported to be associated with this reaction. Histopathological examination, immunhistochemistry, clonality tests, and patch tests are mandatory for diagnosis and differential diagnosis. We present a 48-year-old male with a four years history of a relapsing erythematous plaque on the glans penis. Topical corticosteroids had been prescribed but he complained of relapse upon withdrawal. Histopathological examination was consistent with LCD. Thin layer rapid use epicutaneous patch test result was (++) for disperse blue and nickel sulfate. We present this case because of its rarity and unusual localization. This kind of allergic contact dermatitis should be remembered in differential diagnosis of nonspesific pruritic plaques over the genital region.

Molecular structure-adsorption study on current textile dyes

This study was performed to investigate the adsorption of a diverse set of textile dyes onto granulated activated carbon (GAC). The adsorption experiments were carried out in a batch system. The Langmuir and Freundlich isotherm models were applied to experimental data and the isotherm constants were calculated for 33 anthraquinone and azo dyes. The adsorption equilibrium data fitted more adequately to the Langmuir isotherm model than the Freundlich isotherm model. Added to a qualitative analysis of experimental results, multiple linear regression (MLR), support vector regression (SVR) and back propagation neural network (BPNN) methods were used to develop quantitative structure-property relationship (QSPR) models with the novel adsorption data. The data were divided randomly into training and test sets. The predictive ability of all models was evaluated using the test set. Descriptors were selected with a genetic algorithm (GA) using QSARINS software. Results related to QSPR models on the adsorption capacity of GAC showed that molecular structure of dyes was represented by ionization potential based on two-dimensional topological distances, chromophoric features and a property filter index. Comparison of the performance of the models demonstrated the superiority of the BPNN over GA-MLR and SVR models.

Respiratory symptoms and pulmonary functions of workers employed in Turkish textile dyeing factories

Dyes are known to be a causative agent of occupational asthma in workers exposed to them. We have evaluated respiratory symptoms among textile workers. The study population comprised 106 exposed workers and a control (unexposed) group. Data were collected by a questionnaire. PFTs (Pulmonary Function Test) were performed. Among the exposed workers 36.8% defined phlegm. Respiratory symptoms were not significantly different between two groups. The employment duration of the exposed workers with phlegm was longer than those without phlegm (p = 0.027). The mean % predicted of FEF(25-75) of the exposed workers was found to be significantly lower than the control (unexposed) group (p = 0.01). Our study suggests that textile dyeing might cause respiratory symptoms in workers.

Decolorization of different textile dyes by Penicillium simplicissimum and toxicity evaluation after fungal treatment

The objective of this study was to investigate the capacity of decolorization and detoxification of the textile dyes Reactive Red 198 (RR198), Reactive Blue 214 (RB214), Reactive Blue 21 (RB21) and the mixture of the three dyes (MXD) by Penicillium simplicissimum INCQS 40211. The dye RB21, a phthalocyanine, was totally decolorized in 2 days, and the others, the monoazo RR198, the diazo RB214 and MXD were decolorized after 7 days by P. simplicissimum. Initially the dye decolorization involved dye adsorption by the biomass followed by degradation. The acute toxicity after fungal treatment was monitored with the microcrustacean Daphnia pulex and measured through Effective Concentration 50% (EC₅₀). P. simplicissimum reduced efficiently the toxicity of RB21 from moderately acutely toxic to minor acutely toxic and it also reduced the toxicity of RB214 and MXD, which remained minor acutely toxic. Nevertheless, the fungus increased the toxicity of RR198 despite of the reduction of MXD toxicity, which included this dye. Thus, P. simplicissimum INCQS 40211 was efficient to decolorize different textile dyes and the mixture of them with a significant reduction of their toxicity. In addition this investigation also demonstrated the need of toxicological assays associated to decolorization experiments.