SciCombinator

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Concept: Azo dyes

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Purified laccase from Trametes polyzona WR710-1 was used as biocatalyst for bisphenol A biodegradation and decolorization of synthetic dyes. Degradation of bisphenol A by laccase with or without redox mediator, 1-hydroxybenzotriazole (HBT) was studied. The quantitative analysis by HPLC showed that bisphenol A rapidly oxidized by laccase with HBT. Bisphenol A was completely removed within 3 h and 4-isopropenylphenol was found as the oxidative degradation product from bisphenol A when identified by GC-MS. All synthetic dyes used in this experiment, Bromophenol Blue, Remazol Brilliant Blue R, Methyl Orange, Relative Black 5, Congo Red, and Acridine Orange were decolorized by Trametes laccase and the percentage of decolorization increased when 2 mM HBT was added in the reaction mixture. This is the first report showing that laccase from T. polyzona is an affective enzyme having high potential for environmental detoxification, bisphenol A degradation and synthetic dye decolorization.

Concepts: Enzyme, Redox, Nicotinamide adenine dinucleotide, Dye, Triarylmethane dyes, Azo dyes, Acridine, Phthalocyanine

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Reactive black B (RBB) is a group of azo dyes that are widely used in the textile industry. In this study, a new microbial strain was isolated from azo dye contaminated river sediment which is capable of degrading RBB. The strain was identified as Bacillus cereus strain HJ-1 by 16S rRNA gene sequences analysis. The optimal conditions for RBB decolorization by B. cereus strain HJ-1 are: 25°C, pH 8, 1 CMC of triton X-100, 0.15gL(-1) of added yeast extract, 0.125gL(-1) of added glucose and static culture. Then the toxicity of RBB on the green algae Chlorella vulgaris was determined. The results showed that the median effective concentration (EC(50)) of RBB for C. vulgaris is 48mgL(-1) and toxicity will really decrease after decolorization. In the end, B. cereus strain HJ-1 was amended into the origin river sediment and analyzed the whole microbial community structure of river sediment samples by PCR-DGGE technique. The result showed that B. cereus strain HJ-1 could survive in the river sediment after 12d of incubation. Based on this work, we hope that these findings could provide some useful information for applying the decolorization of RBB in our environment.

Concepts: Microbiology, Ribosomal RNA, 16S ribosomal RNA, Dye, Azo compound, Pigments, Azo dyes, Chlorella

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Azo dyes are generally resistant to biodegradation due to their complex structures. Acid orange II is one of the most widely used dyes in the textile industry. The influence of bovine serum albumin (BSA) in different concentrations, pH, and time of contact on Orange II was investigated using kinetics and adsorption-isotherm experiments. The results showed that the maximum colour removed from dye/albumin was 99.50% and that a stable dye-protein complex had been formed at pH 3.5 and in a proportion of 1:3 (v/v), respectively. The synthetic effluent did not show toxicity to the microcrustacean Artemia salina, and showed a CL(50) equal to 97 µg/mL to azo dye orange II. Additionally, the methodology was effective in removing the maximum of orange II using BSA by adsorption at pH 3.5 which mainly attracted ions to the azo dye during the adsorption process. This suggests that this form of treatment is economical and easy to use which potentially could lead to bovine serum albumin being used as a sorbent for azo dyes.

Concepts: Serum albumin, Dye, Bovine serum albumin, Azo compound, Pigments, Azo dyes

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When speed is of the essence: After photoisomerization to its metastable cis form, an azo dye must undergo fast thermal isomerization back to the trans form to be suitable for real-time information transmission. The azopyrimidine shown has a relaxation time, τ, of just 40 ns under physiological conditions as well as high biocompatibility, as determined by Escherichia coli growth in its presence.

Concepts: Time, Escherichia coli, Dye, Azo compound, Azo compounds, Celestial mechanics, Azo dyes, Azobenzene

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Amaranth (E123) and Allura red (E129), very important food azo dyes used in food, drug, paper, cosmetic and textile industries, were assessed for their genotoxic potential through comet assay in yeast cells. Comet assay was standardized by with different concentration of H(2)O(2). Concentrations of Amaranth and Allura red were maintained in sorbitol buffer starting from 9.76 to 5,000 μg/mL and 1 × 10(4) cells were incubated at two different incubation temperatures 28 and 37°C. Amaranth (E123) and Allura red (E129) were found to exhibit their genotoxic effect directly in Saccharomyces cerevisiae. No significant genotoxic activity was observed for Amaranth and Allura red at 28°C but at 37°C direct relation of Amaranth concentration with comet tail was significant and no positive relation was seen with time exposure factor. At 37°C the minimum concentration of Amaranth and Allura red at which significant DNA damage observed through comet assay was 1,250 μg/mL in 2nd h post exposure time. The results indicated that food colors should be carefully used in baking products as heavy concentration of food colors could affect the fermentation process of baking.

Concepts: Yeast, Saccharomyces cerevisiae, Brewing, Dye, E number, Azo dyes, Allura Red AC, Food coloring

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An efficient method was developed for the simultaneous determination of seven commonly used synthetic sulfonate dyes (Ponceau 4RC, Sunset yellow, Allura red, Azophloxine, Ponceau xylidine, Erythrosine and Orange II) in animal feed and meat using high performance liquid chromatography (HPLC-DAD) and tandem mass spectrometry (HPLC-MS/MS). Ethanol-ammonia-water (80:1:19, V/V/V) solution was used as extract solution, which can extract target species while reducing interference from the sample matrices. The recoveries of these 7 dyes in animal feed and chicken meat were between 71% and 97% with relative standard deviations less than 14.8%. HPLC-MS/MS was employed as a further means of confirmation to assure accuracy of the results. Limits of detection for these dyes were in the range of 0.02-21.83 ng mL(-1). The proposed method can be applied to confirmative screening of seven commonly used food colorants in feed and meat samples.

Concepts: Mass spectrometry, High performance liquid chromatography, Analytical chemistry, Chicken, Tandem mass spectrometry, Azo dyes, Food coloring, Food colorings

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A central composite design was used to investigate the influence of the main process parameters on the degradation of Reactive Green 19 (RG19) azo dye by the UV/H2O2 treatment. The combined use of UV radiation and H2O2 resulted in the decolorization and dearomatization of the dye. They were monitored by measuring the spectral changes occurring, respectively, in the visible and UV regions of the dye spectrum. RG19 degradation was found to be practically complete over a time of 15-60 min, for decolorization, and 50-200 min, for dearomatization, depending on the applied conditions. Both processes followed apparent first-order kinetics. The associated rate constants were used as the response variables and their dependence on initial dye and H2O2 concentrations, pH and reaction time was investigated by the response surface methodology. Response surface plots for the decolorization and dearomatization processes were very similar in shape. For both processes, the initial dye and H2O2 concentrations were the key factors controlling dye degradation.

Concepts: Dye, Azo compound, Response surface methodology, Azo dyes

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This work describes the efficiency of photoelectrocatalysis based on Ti/TiO2 nanotubes in the degradation of the azo dyes Disperse Red 1, Disperse Red 13 and Disperse Orange 1 and to remove their toxic properties, as an alternative method for the treatment of effluents and water. For this purpose, the discoloration rate, total organic carbon (TOC) removal, and genotoxic, cytotoxic and mutagenic responses were determined, using the comet, micronucleus and cytotoxicity assays in HepG2 cells and the Salmonella mutagenicity assay. In a previous study it was found that the surfactant Emulsogen could contribute to the low mineralization of the dyes (60% after 4 h of treatment), which, in turn, seems to account for the mutagenicity of the products generated. Thus this surfactant was not added to the chloride medium in order to avoid this interference. The photoelectrocatalytic method presented rapid discoloration and the TOC reduction was ≥87% after 240 min of treatment, showing that photoelectrocatalysis is able to mineralize the dyes tested. The method was also efficient in removing the mutagenic activity and cytotoxic effects of these three dyes. Thus it was concluded that photoelectrocatalysis was a promising method for the treatment of aqueous samples.

Concepts: Mutation, Water pollution, Cytotoxicity, Toxicity, Dye, Azo compound, Mutagen, Azo dyes

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A novel bacterium was isolated from the soil of Ichalkaranji textile industrial area. Through 16S rRNA sequence matching and morphological observation it was identified as Lysinibacillus sp. RGS. This strain has ability to decolorize various industrial dyes among which, it showed complete decolorization and degradation of toxic sulfonated azo dye C.I. Remazol Red (at 30°C, pH 7.0, under static condition) with higher chemical oxygen demand (COD) reduction (92%) within 6 h of incubation. Various parameters like agitation, pH, temperature and initial dye concentrations were optimized to develop faster decolorization process. The supplementation of cheap co-substrates (e.g., extracts of agricultural wastes) could enhance the decolorization performance of Lysinibacillus sp. RGS. Induction in oxidoreductive enzymes presumably indicates involvement of these enzymes in the decolorization/degradation process. Analytical studies of the extracted metabolites confirmed the significant degradation of Remazol Red into various metabolites. The phytotoxicity assay (with respect to plants Phaseolus mungo and Sorghum vulgare) revealed that the degradation of Remazol Red produced nontoxic metabolites. Finally Lysinibacillus sp. RGS was applied to decolorize mixture of dyes and actual industrial effluent showing 87% and 72% decolorization (in terms of decrease in ADMI value) with 69% and 62% COD reduction within 48 h and 96 h, respectively. The foregoing result increases the applicability of the strain for the treatment of industrial wastewaters containing dye pollutants.

Concepts: Enzyme, Ribosomal RNA, 16S ribosomal RNA, Toxicology, Dye, Azo compound, Pigments, Azo dyes

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A two stage sequential Photo-Fenton’s oxidation followed by aerobic biological treatment using two white rot fungi P. ostreatus IBL-02 (PO) and P. chrysosporium IBL-03 (PC) was performed to check decolorization and to enhance mineralization of azo dye Reactive Blue 222 (RB222). In the first stage, selected dye was subjected to Photo-Fenton’s oxidation with decolorization percentage ≈90 % which was further increased to 96.88 % and 95.23 % after aerobic treatment using two white rot fungi P. ostreatus IBL-02 (PO) and P. chrysosporium IBL-03 (PC), respectively. Mineralization efficiency was accessed by measuring the water quality assurance parameters like COD, TOC, TSS and Phenolics estimation. Reduction in COD, TOC, TSS and Phenolics were found to be 95.34 %, 90.11 %, 90.84 % and 92.22 %, respectively in two stage sequential processes. The degradation products were characterized by UV-visible and FTIR spectral techniques and their toxicity was measured. The results provide evidence that both fungal strains were able to oxidize and mineralize the selected azo dye into non-toxic metabolites.

Concepts: Enzyme, Fungus, Redox, Electrochemistry, Cellular respiration, Dye, Azo compound, Azo dyes