Optimal Conditions For Decolorization Research Articles

Evaluation of Bioremediation Potentiality of Bacillus mojavensis Isolated from Wastewater for the Elimination of Reactive Yellow 145 and Methyl Orange.

Textile industry waste has become one of the largest polluters in the world. In recent years, there has been a growing awareness of the need for sustainable and eco-friendly practices for the treatment of dye-laden effluents. Overall, this study highlights the potential of bioremediation as a sustainable solution for wastewater treatment. The Bacillus mojavensis isolated from wastewater and identified using 16S rRNA degraded reactive yellow 145 and methyl orange in 36h of incubation, this decolorization was affected by pH, temperature, dye concentration, glucose concentration, source of nitrogen, type of dye, and agitation. Our study found that the optimal conditions for total decolorization of dyes were achieved by incubating B. mojavensis at 46°C, pH 9, with 1g/L of glucose and 2g/L of peptone. The azoreductase activity, FT-IR analysis, and UV-visible spectrum before and after total decolorization indicated that it was a dye degradation rather than biosorption in surface Celle. In addition, the study of phytotoxicity show the metabolites of degradation are not phytotoxic in Lens esculenta seeds. In conclusion, our results suggest the use of this bacterium as an environmentally friendly and also cost-effective method, making it an attractive option for industries looking to reduce their environmental impact.

A Potentially Practicable Halotolerant Yeast Meyerozyma guilliermondii A4 for Decolorizing and Detoxifying Azo Dyes and Its Possible Halotolerance Mechanisms.

In this study, a halotolerant yeast that is capable of efficiently decolorizing and detoxifying azo dyes was isolated, identified and characterized for coping with the treatment of azo-dye-containing wastewaters. A characterization of the yeast, including the optimization of its metabolism and growth conditions, its detoxification effectiveness and the degradation pathway of the target azo dye, as well as a determination of the key activities of the enzyme, was performed. Finally, the possible halotolerance mechanisms of the yeast were proposed through a comparative transcriptome analysis. The results show that a halotolerant yeast, A4, which could decolorize various azo dyes, was isolated from a marine environment and was identified as Meyerozyma guilliermondii. Its optimal conditions for dye decolorization were ≥1.0 g/L of sucrose, ≥0.2 g/L of (NH4)2SO4, 0.06 g/L of yeast extract, pH 6.0, a temperature of 35 °C and a rotation speed of ≥160 rpm. The yeast, A4, degraded and detoxified ARB through a series of steps, relying on the key enzymes that might be involved in the degradation of azo dye and aromatic compounds. The halotolerance of the yeast, A4, was mainly related to the regulation of the cell wall components and the excessive uptake of Na+/K+ and/or compatible organic solutes into the cells under different salinity conditions. The up-regulation of genes encoding Ca2+-ATPase and casein kinase II as well as the enrichment of KEGG pathways associated with proteasome and ribosome might also be responsible for its halotolerance.

Efficient decolorization and detoxification of azo dyes by a halotolerant yeast Meyerozyma guilliermondii A3 with relatively low external carbon source

Decolorization and detoxification of azo dyes by a newly isolated halotolerant yeast was investigated in the present study. This work included isolation and identification of the halotolerant yeast, optimization of its growth and decolorization conditions, proposal of dye decolorization pathways, and analysis of the transcriptomic responses to dye and salt stress. The results showed that a halotolerant yeast which was capable of efficiently decolorizing various azo dyes under saline conditions was isolated and identified as Meyerozyma guilliermondii (strain A3). The optimal conditions for dye decolorization and yeast growth were as follows: glucose (sucrose was also suitable) ≥1.0 g/L, (NH4)2SO4 ≥ 0.2 g/L, yeast extract ≥0.04 g/L, salinity (NaCl concentration) ≤30.0 g/L, temperature 30-35 °C, pH 6.0–7.0 and rotation speed ≥160 rpm. The target dye Acid Red B (ARB) was significantly detoxified by the yeast A3 intracellularly through the processes including cleavage of azo bonds, ortho-hydroxylation (monooxygenation pathway), oxidative desulfurization/deaminization, ring opening of substituted naphthalene, and TCA cycle. Genes encoding oxidoreductases and sugar transporters were universally up-regulated under dye stress, and those encoding cell wall regulators were also up-regulated under salt stress. Meanwhile, genes encoding oxidoreductases and sugar transporters were universally down-regulated under salt stress.

Decolorization and degradation of reactive orange 16 by Bacillus stratosphericus SCA1007.

Efficient bacterial strain was isolated from the dye contaminated area and identified as Bacillus stratosphericus SCA1007 based on 16S rRNA genesequence (GenBank under accession number KY992944). This isolate was selected based on its potential to efficiently decolorize reactive orange 16 dye which is extensively used in textile industries. Various culture conditions like dye concentration, temperature, pH, salinity, and additional nitrogen source were optimized in the present study. The optimal conditions for decolorization of reactive orange 16 was found to be: dye concentration 150mg/L, pH 7, temperature 35°C, and yeast extract as nitrogen source. The isolate was also resistant to 4% saline culture condition. Decolorization and degradation of dye were confirmed through UV-visible spectroscopy, Fourier transform infrared (FTIR) and liquid chromatography-mass spectrometry analysis (LC-MS). Toxicity studies were performed on Escherichiacoli and Vigna radiata to confirm the non-toxic nature of the degraded metabolites. This is the first study demonstrating complete decolorization of reactive orange 16 dye by Bacillus stratosphericus SCA1007 at high salinity within 10h of incubation under optimized conditions.

Decolorization of acid blue 29, disperse red 1 and congo red by different indigenous fungal strains

Azo dyes are toxic and recalcitrant environmental pollutants in wastewater and soil in many industrial sites in Asia and Arabic countries. The aim of this study was to find fungal species useful in wastewater treatment and soil remediation efforts. We assessed the ability of different indigenous Aspergillus strains (i.e. A. flavus, A. fumigatus, A. niger and A. terreus) to degrade the azo dyes Acid Blue 29 (AB29), Disperse Red 1 (DR1) and Congo Red (CR). The optimal conditions for dye decolorization by the above-mentioned strains appeared to be as follows: temperature range 30–35 °C, pH 7, glucose as the carbon source (10 g/L), ammonium sulphate as the nitrogen source (1.5 g/L) and 100 mg/L initial dye concentration. The Aspergillus strains decolorized all azo dyes more than 86%. The HPLC and GC-MS analyses confirmed that aniline (retention time 9.0 min), 3-nitroaniline (retention time 15.92 min), 4-nitroanline (retention time 17.81 min), N,N’ diethyl-1,4-phenylendiamine (retention time 18.184 min), and benzidine (retention time 15.07 min) were formed as the intermediate metabolites of dye degradation. All Aspergillus strains decolorized 85% of the dyes in synthetic wastewater.

Decolorization of Reactive Black 5 and Reactive Red 152 Azo Dyes by New Haloalkaliphilic Bacteria Isolated from the Textile Wastewater.

Textile wastewaters are usually alkali and saline, so using haloalkaliphilic bacteria can be the best option for the treatment of wastewater. This study aimed at the decolorization of textile Reactive Black 5 and Reactive Red 152 dyes using new haloalkaliphilic bacteria isolated from the textile wastewater. Among 50 strains of bacteria isolated from the effluent of Kashan textile industry, three bacterial strains, namely D1, D2 and E49, exhibited high decolorization abilities for Reactive Black 5 and Reactive Red 152 dyes. Decolorization was evaluated through spectrophotometry at maximum absorbance wavelengths of 607 and 554nm for Reactive Black 5 and Reactive Red 152, respectively. The highest decolorization percentage was observed at a dye concentration of 50mgL-1. Aerobic conditions, 5% of the yeast extract and salt, 10% of peptone and glucose as nitrogen and carbon sources, respectively, and a pH range of 9-12 were considered as the optimal conditions for decolorization. The consortium of three haloalkaliphilic isolates showed a remarkable ability for decolorization of the Reactive Black 5 (87%) and Reactive Red 152 (85%) dyes. The consortium exhibited higher decolorization ability for the textile effluent, compared to individual bacterial inoculations. According to phenotypic characterization experiments and phylogenetic analyses based on comparing 16S rDNA sequence, the mentioned strains belonged to the genus Halomonas.

Optimization of diazo dye disappearance by the UV/H2O2 process using the Box-Behnken design.

The purpose of this study was to apply the experimental Box-Behnken design (BBD) to evaluate the effect and, therefore, the optimal values of three chosen factors on the efficiency of the UV/H2O2 process to decolorize Ponceau S (PS) aqueous solutions. The factors studied at three levels were the irradiated volume of dye solution, the dye solution turbidity and the H2O2 dosage. The equations generated, analysis of variance (ANOVA), contour plots and response surface plots were used to analyze the relationship between independent variables and the outcomes of experiments. The fitted model was significant, with an adjusted coefficient of determination (adj-R2 = 0.9835). The results showed that factors such as H2O2 dosage and irradiated volume were the main parameters that affected the decolorization efficiency of the PS aqueous solution, while the turbidity had a slight effect on the response. In addition, significant values were obtained for irradiated volume and H2O2 dosage interaction and square terms of all studied factors. Furthermore, the optimal conditions for decolorization of the PS aqueous solution were found to be an irradiated volume of 257.59 mL, a turbidity of 13 NTU and an H2O2 dosage of 1.76 mM.

Decolorization and detoxification of textile wastewaters by recombinant Myceliophthora thermophila and Trametes trogii laccases.

Laccases are multi-copper oxidoreductases with broad biotechnological applications. Here, we report detailed biochemical characterization of purified recombinant laccases originating from Myceliophthora thermophila (MtL) and Trametes trogii (TtL). We identified optimal conditions for decolorization of commercial dyes and textile wastewater samples. We also tested the toxicity of decolorized wastewater samples using human peripheral blood mononuclear cells. MtL and TtL were expressed in Saccharomyces cerevisiae, and secreted enzymes were purified by consecutive hydrophobic and gel chromatography. The molecular masses of TtL (~ 65kDa) and MtL (> 100kDa) suggested glycosylation of the recombinant enzymes. Deglycosylation of MtL and TtL led to 25% and 10% decreases in activity, respectively. In a thermal stability assay, TtL retained 61% and MtL 86% of the initial activity at 40°C. While TtL retained roughly 50% activity at 60°C, MtL lost stability at temperatures higher than 40°C. MtL and TtL preferred syringaldazine as a substrate, and the catalytic efficiencies for ABTS oxidation were 7.5 times lower than for syringaldazine oxidation. In the presence of the mediator HBT, purified TtL almost completely decolorized dyes within 30min and substantially decolorized wastewater samples from a textile factory (up to 74%) within 20h. However, products of TtL-catalyzed decolorization were more toxic than MtL-decolorized products, which were almost completely detoxified.

Response surface methodology mediated optimization of decolorization of azo dye amido black 10B by Kocuria kristinae RC3

The bacterium, Kocuria kristinae RC3 capable of decolorizing sulfonated azo dye, amido black 10B was isolated using enrichment technique and identified by 16s rRNA gene sequencing. A maximum decolorization of 74.19% was achieved in the mineral salt medium at 37 °C and 24 h of incubation time. Effect of medium components and process conditions on decolorization efficiency was studied using response surface methodology involving a central composite design. Further, the interactions between the process conditions, i.e., pH, temperature, cell mass, dye concentration, and medium components, i.e., glucose, yeast extract, K2HPO4 and (NH4)2SO4 concentration were modeled and investigated. The predicted values were found to be in good correlation with experimental values. The process conditions were optimized which resulted in 93.0% dye decolorization by the bacteria in 24 h. The optimized process conditions for maximum decolorization of amido black 10B by the bacterium were pH (7.4), cell mass (2.9 g/L), temperature (35.3 °C) and dye concentration (137.46 mg/L) in 24 h. The optimal medium conditions for maximum decolorization determined by RSM were glucose (3.17 g/L), yeast extract (1.05 g/L), K2HPO4 (1.66 g/L) and (NH4)2SO4 (1.06 g/L). Under these conditions, maximum decolorization of 96.83% was achieved in 24 h. The results demonstrated that K. kristinae RC3 could be employed for the treatment of amido black 10B contaminated wastewater/effluents.

A quasi-homogeneous catalysis and electron transfer chain for biodecolorization of azo dye by immobilized phenazine redox mediator

The anaerobic bio-reduction rate of many different contaminants is slow due to the limitations and efficiencies of electron transfer. In this study, the phenazine immobilized in hydrophilic material was tested as a redox mediator (RM) and quasi-homogeneous catalysis to reduce the mass transfer limitation and increase the decolorization efficiency. Neutral red (NR) was immobilized to polyacrylic acid (PAA) hydrogel by chemical reaction and obtained a content of NR as high as 3.58 mmol cm−3 of PAA. The novel functional material (PAA-NR), with three-dimensional polymeric network with high porosity and water contents (92–98%, w/v) achieved 13.5 fold higher in the anaerobic decolorization efficiency compared to the control. The optimal conditions for decolorization with PAA-NR hydrogel were 40 °C and pH 8.0. Additionally, the electron transfer mechanism of decolorization was investigated by testing with six inhibitors. NADH and FAD chains were involved in the decolorization process. PAA-NR acted as an insoluble redox mediator to accelerate Reactive Brilliant Red K-2BP (K-2BP) reduction through mediating electron transfer between the azoreductase and K-2BP, resulting in higher electron transfer and decolotization efficiency. This immobilizing technology extended the RM application and demonstrated high catalytic activity on pollutant anaerobic transformation.

Aerobic decolorization and degradation of Acid Orange G (AOG) by suspended growing cells and immobilized cells of a yeast strain Candida tropicalis TL-F1.

In this study, aerobic decolorization and degradation of azo dye Acid Orange G (AOG) by both suspended growing cells and immobilized cells of a yeast strain Candida tropicalis TL-F1 were studied. The effects of different parameters on decolorization of AOG by both growing suspended and immobilized strain TL-F1 were investigated. Furthermore, a possible decolorization mechanism of AOG was proposed through analyzing metabolic intermediates using UV-vis and high-performance liquid chromatography-mass spectrometry (HPLC-MS) methods. Strain TL-F1 could decolorize AOG in both liquid and solid mediums through degradation. The optimal conditions for decolorization with suspended growing cells of strain TL-F1 were as follows: 6-10g/L sucrose, 5-7g/L urea, ≥6% (v/v) inoculation size, ≥160rpm, 35-40°C, and pH 5.0-6.0; and those for immobilized cells, the conditions were as follows: 4-6g/L glucose, 0.2-0.4g/L urea, 6-10g/L (wet cell pellets) inoculation size, ≥160rpm, 35-40°C, and pH 5.0-7.0. Results of UV-vis scanning spectra suggested that AOG was decolorized through biodegradation, and the possible pathway was proposed through the results of HPLC-MS analysis and related literature. This is a systematic research on aerobic decolorization and degradation of AOG by both suspended and immobilized cells of a C. tropicalis strain.

Studies on decolorization of reactive blue 19 textile dye by Coprinus plicatilis

BackgroundStudies were carried on the decolorization of the textile dye reactive blue 19 (RB 19) by a novel isolate of Coprinus plicatilis (C. plicatilis) fungi. We describe an in vitro optimization process for decolorization and its behavior under different conditions of carbon and nitrogen sources, pH, temperature and substrate concentration.ResultsThe optimal conditions for decolorization were obtained in media containing intermediate concentrations of ammonium oxalate and glucose (10 g/L) as nitrogen and carbon sources, respectively, at 26°C and pH = 5.5. Maximum decolorization efficiency against RB 19 achieved in this study was around 99%. Ultra-violet and visible (UV-vis) spectrophotometric analyses, before and after decolorization, suggest that decolorization was due to biodegradation.ConclusionsThis effect was associated with laccase enzyme displaying good tolerance to a wide range of pH values, salt concentrations and temperatures, suggesting a potential role for this organism in the remediation of real dye containing effluents. In conclusion, laccase activity in C. plicatilis was firstly described in this study.

Strategies to Decolorize High Concentrations of Methyl Orange Using Growing Cells ofLactobacillus caseiTISTR 1500

Batch, fed-batch, and continuous fermentation was used in the processing of methyl orange decolorization using growing cells of Lactobacillus casei TISTR 1500. This report presents the optimal conditions for methyl orange decolorization by the strain TISTR 1500 in modified MRS via a central composite design (CCD) experiment. In particular, the highest decolorization efficiencies were obtained with 13.41 g/L of meat extract, and with 10.89 g/L of yeast extract at pH 6.88 at 35 °C. Under the optimal conditions, the rate of decolorization increased to 322% of that obtained for un-optimized MRS medium. The high concentration of methyl orange (5 g/L) was completely degraded within 9 h in batch fermentation. The total methyl orange load with 8.075 g/L was also decolorized in fed-batch fermentation within 13 h, and the biomass of the strain dramatically decreased after an incubation time of 8 h due to a shortage of sucrose. In the continuous system with a dye-loading rate of 600 mg/L/h and a total of loaded azo dye of 7.2 g/L, high efficiency of methyl orange removal was significantly high, at 98%.

The Potential Application of Light-Emitting Diode on Biodecolorization of Azo Dye

In the previous study, the decolorization of azo dye was significantly enhanced by the light irradiation. The aim of this study is to investigate the effect of methyl orange decolorization under light-emitting diode (LED). The effect of media, pHs, and nitrogens on methyl orange decolorization by freely suspended cells are examined. The results showed that the optimal conditions for the methyl orange decolorization by theTsukamurellasp. J8025 are incubation at 30 °C and pH 8.0 in YEME medium under white-light LED.

Kinetic characteristics of biodegradation of methyl orange by Pseudomonas putida mt2 in suspended and immobilized cell systems

Azo dyes, which are considered the most recalcitrant and persistent among all groups of dye, were biodegraded by various types of bacteria. In this study, the decolorization of methyl orange was determined under various conditions by non-immobilized and immobilized Pseudomonas putida mt2. In both systems, the decolorizations were more favorable under anoxic condition. Optimal conditions for decolorization were investigated. The optimal temperature for suspended cell operation is in the range between 33 and 35°C and the decolorization seems not to be suitable in acidic condition. However, the optimal range of pH and temperature in the immobilized cell system were obtained at 7–9 and 35–37°C, respectively. Kinetics parameters of νmax and km were predicted up to 7.5mg/(gh) and 283gL−1, respectively, for non-immobilized system; and 6.3mg/(gh) and 257gL−1, respectively, for immobilized Ca-alginate system. Mass transfer coefficients were calculated as 0.75×10−5 and 6.20×10−5 for each system.

Decolorization of azo dye reactive black B by Bacillus cereus strain HJ-1

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 (EC50) 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.

Decolorization of Direct Yellow R Dye from Aqueous Solution by Aluminum Anode Electrochemical

The present study applied Aluminum anode electrochemical method to decolorize direct yellow R wastewater. Experiments were conducted in electrochemical cell system with dimensions of 60 mm ´ 40 mm ´ 2 mm, a steel cathode and aluminum anode. Decolorization efficiency and electrical energy consumption were also calculated to compare optimal values. The effects of factors consist of current density, initial pH, initial dye concentration and electrolyte solution concentration on color removal efficiency have been also investigated. The results of study suggested that direct yellow R dye decolorization was very effective by using treatment technique applied in the study. The optimal values of impact factors were also indicated by. The initial dye concentration of 50 mg/l, initial pH value of 6.76, and current density of 2.5 mA/cm2 and Na2SO4 electrolyte concentration of 0.1mol/L were optimal conditions for dye decolorization. Besides that, the dye decolorization might reached the highest efficiency of 96.1% once it was conducted at temperature of 20°C, electrode distance of 16 mm and electrolyte time of 60 minutes. Energy consumption for decolorization in conditions mentioned above was 2.399 kWh/kg-dye.

Highly efficient decolorization of Malachite Green by a novel Micrococcus sp. strain BD15

Malachite Green (MG) is used for a variety of applications but is also known to be carcinogenic and mutagenic. In this study, a novel Micrococcus sp. (strain BD15) was observed to efficiently decolorize MG. The purposes of this study were to explore the optimal conditions for decolorization and to evaluate the potential use of this strain for MG decolorization. Optical microscope and UV-visible analyses were carried out to determine whether the decolorization was due to biosorption or biodegradation. A Plackett-Burman design was employed to investigate the effect of various parameters on decolorization, and response surface methodology was then used to explore the optimal decolorization conditions. Kinetics analysis and antimicrobial activity tests were also performed. The results indicated that the decolorization by the strain was mainly due to biodegradation. Concentrations of MG, urea, and yeast extract and inoculum size had significantly positive effects on MG decolorization, while concentrations of CuCl(2) and MgCl(2), and temperature had significantly negative effects. The interaction between different parameters could significantly affect decolorization, and the optimal conditions for decolorization were 1.0g/L urea, 0.9g/L yeast extract, 100mg/L MG, 0.1g/L inoculums (dry weight), and incubation at 25.2°C. Under the optimal conditions, 96.9% of MG was removed by the strain within 1h, which represents highly efficient microbial decolorization. Moreover, the kinetic data for decolorization fit a second-order model well, and the strain showed a good MG detoxification capability. Based on the results of this study, we propose Micrococcus sp. strain BD15 as an excellent candidate strain for MG removal from wastewater.

New Synthetic Process of Dicyclopentadiene Phenol Resin

Dicyclopentadiene phenol resin(DPR) was prepared from dicyclopentadiene and phenol with methane sulfonic acid as the catalyst.The optimum conditions for the synthesis were as follows:n(phenol)/n(DCPD)=5;w(catalyst)=1.5%;temperature=120 ℃;time=5 h;yield=89%.The light yellow dicyclopentadiene phenol resin was obtained by the decolouring of catalytic-hydrogenation.The optimal conditions for the decolorization were as follows:hydrogen pressure=1.5 MPa,w(Pd/Al2O3)=0.5%,temperature=80 ℃,yield=89%.FT-IR and 1H NMR analysis identified the desired product.The product properties reached the international quality standards.

Decolorization of Reactive Dark Blue K-R by the synergism of fungus and bacterium using response surface methodology

The objective of this study was to investigate the potential ability of decolorizing Reactive Dark Blue K-R by the synergism of fungal strain Penicillium sp. QQ and bacterial strain Exiguobacterium sp. TL. The optimal conditions for decolorization determined by response surface methodology (RSM) were as follows: 12.5% (w/v) of both strains QQ and TL, 0.19% (w/v) of glucose, 0.09% (w/v) of yeast extract, pH 7.0, 37 °C and 200 mg/L of initial dye concentration. It was shown that about 97% of 200 mg/L K-R could be decolorized within 24 h under these conditions. Besides, strains QQ and TL co-cultures could decolorize 10 kinds of azo dyes effectively and be still 60% color removal when salinity increased to 15%. And most of the tested metal ions showed little influence on the decolorization except for Ni 2+. The results demonstrated that strains QQ and TL co-cultures could be useful for the practical bioremediation.