Optimization Of Decolorization Research Articles

Factors Influencing Decolourization and Detoxification of Remazol Brilliant Blue R Dye by Aspergillus flavus.

<b>Background and Objectives:</b> Anthraquinone synthetic dyes are widely used in textile, dyeing and paper painting. The discharge of these dyes into the environment causes detriment. The removal of physiochemical dyes is sometimes unsuccessful and expensive. Biological removal is inexpensive, eco-friendly and may break down organic contaminants. In the current work, a fungal technique was applied to decolorize and detoxify dye. <b>Materials and Methods:</b> Dye decolorizing fungi isolation, selection and identification of the most effective isolate and dye decolorization optimization based on carbon and nitrogen sources. In addition, the product's cytotoxicity and metabolites were tested. The enzyme activities were measured to determine dye decolorization. <b>Results:</b> Decolorization of reactive blue 19 dye by the most effective fungal strain isolate (5BF) isolated from industrial effluents were studied. This isolate was identified as <i>Aspergillus flavus</i> based on phenotypic characteristics and confirmed using 18S rRNA gene sequencing. Thin-layer chromatography indicated that this strain is aflatoxins free. Furthermore, metabolites produced from dye treatment with <i>A. flavus</i> were assessed using gas chromatography-mass spectrometry. Toxicity data revealed that <i>A. flavus</i> metabolites were not toxic to plants. Using a one-factor-at-a-time optimization technique, a maximum decolorization percentage (99%) was obtained after 72 hrs in the presence of mannitol and NH<sub>4</sub>NO<sub>3</sub> or NH<sub>4</sub>Cl as carbon and nitrogen sources. Two enzymes (laccase and manganese peroxidase) were shown to be active during dye decolorization by <i>A. flavus</i>. <b>Conclusion:</b> The <i>A. flavus</i> strain was shown to be safe when it came to removing dye from a synthetic medium with high efficiency and their metabolites had no negative influence on the environment. As a result, this strain will be used in the future for dye wastewater bioremediation.

Biostoning of textile effluent with laccase enzyme

The incessant release of textile effluent comprehending dyes and heavy metals which impacts on aquatic life. Current study used an enzyme to eradicate phenolic compounds and synthetic dyes from textile effluent by an indigenously isolated white rot fungus Pleurotus ostreatus- P1 has been cultured and indicated the utmost laccase activity with synthetic medium; as reacting substrate for dye decolorization. The textile effluent decolorization optimization has been conducted with different concentrations of laccase enzyme, temperature and pH. The 90% effluent decolorization was obtained by applying response surface methodology (RSM) conditions temperature, crude laccase enzyme and pH, 25˚C, 13.5 U/ml and 5 respectively. The predicted values were validated with experimental values, that confirms the steadiness of the model.
 Bangladesh J. Sci. Ind. Res.56(2), 115-124, 2021

Decolorization of textile azo dye Novacron Red using bacterial monoculture and consortium: Response surface methodology optimization.

The present study was intended toward the optimization of a textile dye Novacron Red decolorization by single and mixed culture of Bacillus strains namely, B.firmus, B.filamentosus and B.subterraneus. Optimization of dye decolorization using Bacillus monocultures was conducted using central composite design. The maximum dye decolorization achieved under optimized conditions for B.firmus, B.filamentosus and B.subterraneus was 89.24%, 88.28% and 88.45%, respectively. The effect of various consortia of selected Bacillus strains on dye removal was evaluated by applying a mixture design. The best dye (100mg/L) decolorization yield (84%) was achieved using the consortium of B.filamentosus and B.subetrraneus.The Fourier Transform Infrared Spectroscopy analyses confirmed biodegradation potential of the two Bacillus strains. The results highlighted the potential of mono- and co-cultures of Bacillus strains for application in textile wastewater treatment. PRACTITIONER POINTS: Novel dye-decolorizing Bacillus strains were isolated from marine sediment. Optimization of decolorization was conducted using response surface methodology. Efficient decolorization of textile dye by Bacillus strains on mono- and co-cultures. The efficiency of the consortium B.filamentosus and B.subetrraneus on dye removal.

Mycoremediation of azo dyes using Cyberlindnera fabianii yeast strain: Application of designs of experiments for decolorization optimization.

This study investigated the dye decolorization capacity of three yeast strains. Cyberlindnera fabianii was shortlisted for its high decolorization capacity and was further tested on various azo dyes. Based on the color of the biomass, and the UV-Vis analysis, Acid Red 14 was selected as a model dye, to examine the enzymatic biodegradation. The results showed significant increase in the intracellular and extracellular activities of laccase, tyrosinase, manganese peroxidase, and azoreductase. Phytotoxicity assessment indicated that the AR14 biodegradation by-products were not phytotoxic compared to the original dye molecules. Regarding the decolorization optimization, the screening of factors using the Plackett-Burman design showed that pH, dye concentration, and shaking speed had significant effects. These factors and their combined effect were evaluated using response surface methodology with the Box-Behnken model. The pH was the most significant factor, followed by dye concentration. The analysis of the contour plot and the 3D response surface diagram showed that the decolorization was inversely proportional to the increase in the initial dye concentration, but proportional to the initial pH and shaking speed. At optimal conditions (pH=5.154, AR14=50mg/L), C.fabianii could decolorize more than 97% of AR14 within 12hr. PRACTITIONER POINTS: Cyberlindnera fabianii is a successful candidate for dye mycoremediation. Oxidase and reductase are the key enzymes involved in the biodegradation of azo dyes. By-products of Acid red 14 biodegradation are not phytoxic compared to the original dye. Design of experience tools enables to determine optimum conditions for efficient decolorization.

Photoreduction of Dye with Noble Metal Gold Permeated with Metal Oxide Titania.

Photoactive degradation of textile malachite green (MG), methylene blue (MB) dyes has been permeated on metal oxide TiO₂ nanoparticles under sunlight. Semiconductor photocatalysis is a promising method for removal of toxic chemicals from wastewater produced by industry. Due to tunable bandgap, TiO₂ among various semiconductor studied mostly. Large band gap (UV active) and recombination of exciton in TiO₂ less active in photo degradation. Noble metals such as gold nanoparticles deposited on TiO₂ surface increased the optical activity and to shift optical response to visible region. Degradation detail has been carried out by characterisation such as XRD, UV-Vis, PL, TEM, and SEM for MG and MB textile dyes under sunlight irradiation. UV-visible absorption spectra and PL spectra shows that photo-response of as prepared sample is extended from UV to visible region. PL intensity decreases with increases in concentration of Au nanoparticles, decreases in intensity in optical spectra of Au-TiO₂ composites shows that charge transfer process dominates. Au-TiO₂ plays an essential role in enhancing photocatalytical activity. Decolorization optimization depends on catalyst concentration, Dye concentration, light intensity and, irradiation time.

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.

Modeling and optimization of decolorization of C.I. Reactive Orange 16 via SO4.- radicals by response surface methodology

Modeling and optimization of decolorization of C.I. Reactive Orange 16 via SO4.- radicals by response surface methodology

Decolorization of molasses-based distillery wastewater by means of pulse electro-Fenton process

The decolorization of actual molasses wastewater using the electro-Fenton (EF) process was investigated. The optimization of decolorization was performed by means of a Box-Behnken design (BBD), with the operating parameters studied being the applied voltage, H2O2 dosage and reaction time. The results showed that the color removal efficiency reached 88.50% under the optimal conditions, in which 2.86V, 15.8% H2O2/wastewater ratio and 90.7min reaction time were applied. The pulse electro-Fenton (PEF) process using the applied voltage and reaction time in the obtained optimal condition was performed afterward. The effects of pulse frequency, pulse duty cycle, electrode distance, H2O2/wastewater ratio and H2O2 stepwise addition were studied. From the results, under the optimal conditions of 2.5kHz pulse frequency, 25% pulse duty cycle, 2cm electrode distance and 15.8% H2O2/wastewater ratio, the color and COD removal efficiencies reached 89.59% and 40.71%, respectively. Under these conditions, the PEF process could reduce the energy consumption by at least 75% compared with the regular EF process. Additionally, compared with stepwise addition, the single step addition of H2O2 was more effective in color removal.

Application of response surface methodology for optimization of decolorization and mineralization of triazo dye Direct Blue 71 by Pseudomonas aeruginosa.

The decolorization and degradation of Direct Blue 71 were investigated using a mono culture of Pseudomonas aeruginosa. The bacterium was able to decolorize the dye medium to 70.43 % within 48 h under microaerophilic conditions. The medium was then aerated for 24 h to promote the biodegradation of the aromatic amines generated from azo bond cleavage. Reduction in total organic carbon in dye medium was 42.58 % in the microaerophilic stage and 78.39 % in the aerobic stage. The degradation metabolites formed were studied using UV–vis techniques, high performance liquid chromatography, Fourier transform infra red spectroscopy and nuclear magnetic resonance spectroscopy analysis. Data obtained provide evidence for the formation of aromatic amines and their subsequent oxidative biodegradation by a single strain of P. aeruginosa during successive microaerophilic/aerobic stages in the same flask. The influence of incubation temperature (20–45 °C), medium pH (5–10) and initial dye concentration (25–150 mg/L) on decolorization was evaluated to greatly influence decolorization extent. The optimal decolorization conditions were determined by response surface methodology based on three-variable central composite design to obtain maximum decolorization and to determine the significance and interaction effect of the variables on decolorization. The optimal conditions of response were found to be 35.15 °C, pH 8.01 and 49.95 mg/L dye concentration giving an experimental decolorization value of 84.80 %. Very high regression coefficient between the variables and the response (R2 = 0.9624) indicated a good evaluation of experimental data by polynomial regression model.

Manganese Peroxidase H4 Isozyme Mediated Degradation and Detoxification of Triarylmethane Dye Malachite Green: Optimization of Decolorization by Response Surface Methodology

A cDNA encoding for manganese peroxidase isozyme H4 (MnPH4), isolated from Phanerochaete chrysosporium, was expressed in Pichia pastoris, under the control of alcohol oxidase I promoter. The recombinant MnPH4 was efficiently secreted onto media supplemented with hemin at a maximum concentration of 500 U/L, after which purified rMnPH4 was used to decolorize the triarylmethane dye malachite green (MG). Response surface methodology (RSM) was employed to optimize three different operational parameters for the decolorization of MG. RSM showed that the optimized variables of enzyme (0.662 U), MnSO4 (448 μM), and hydrogen peroxide (159 μM) decolorized 100 mg/L of MG completely at 3 h. Additionally, UV-VIS spectra, high-performance liquid chromatography, gas chromatography-mass spectrometry, and liquid chromatography-electrospray ionization/mass spectrometry analysis confirmed the degradation of MG by the formation of main metabolites 4-dimethylamino-benzophenone hydrate, N, N-dimethylaniline (N,N-dimethyl-benzenamine), and methylbenzaldehyde. Interestingly, it was found that rMnPH4 mediates hydroxyl radical attack on the central carbon of MG. Finally, rMnPH4 degraded MG resulted in the complete removal of its toxicity, which was checked under in vitro conditions.

Decolorization of organic dye solution by ozonation; Optimization with response surface methodology

Background: Ozone was used as a strong oxidant for decolorization of solution containing organic dyes. Three azo dyes, CI acid black 1 (AB1), CI acid yellow 19 (AY19) and CI acid orange 7 (AO7) which are widely used colorants in leather dyeing and finishing processes, were quantified with colorimetry. The effects of influential parameters including the ozone dosage, initial concentration of the dyes, initial pH of the solution, and temperature on the decolorization efficiency were studied. Central composite design (CCD) was applied to the optimization of decolorization of the dye solution by ozonation, and a second-order polynomial equation was proposed to predict the process efficiency. Results and discussion: Predicted results were found to be in good agreement with experimental values (R 2 = 0.9365, 0.9643, and 0.9296 for AB1, AY19, and AO7 respectively), which proves the suitability of the model employed and the success of CCD in optimizing the conditions of ozonation process. The variation of process efficiency as a function of independent variables was shown by graphical response surfaces. Conclusions: It was found that response surface methodology could effectively predict and optimize the performance of ozonation process for decolorization of solution containing organic dyes, AB1, AY19, and AO7. Also, the optimum values of the process variables to achieve the maximum decolorization efficiency could be calculated and verified experimentally.

Optimization of decolorization of palm oil mill effluent (POME) by growing cultures of Aspergillus fumigatus using response surface methodology

The conventional treatment process of palm oil mill effluent (POME) produces a highly colored effluent. Colored compounds in POME cause reduction in photosynthetic activities, produce carcinogenic by-products in drinking water, chelate with metal ions, and are toxic to aquatic biota. Thus, failure of conventional treatment methods to decolorize POME has become an important problem to be addressed as color has emerged as a critical water quality parameter for many countries such as Malaysia. Aspergillus fumigatus isolated from POME sludge was successfully grown in POME supplemented with glucose. Statistical optimization studies were conducted to evaluate the effects of the types and concentrations of carbon and nitrogen sources, pH, temperature, and size of the inoculum. Characterization of the fungus was performed using scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and Brunauer, Emmet, and Teller surface area analysis. Optimum conditions using response surface methods at pH 5.7, 35 °C, and 0.57 % w/v glucose with 2.5 % v/v inoculum size resulted in a successful removal of 71 % of the color (initial ADMI of 3,260); chemical oxygen demand, 71 %; ammoniacal nitrogen, 35 %; total polyphenolic compounds, 50 %; and lignin, 54 % after 5 days of treatment. The decolorization process was contributed mainly by biosorption involving pseudo-first-order kinetics. FTIR analysis revealed that the presence of hydroxyl, C-H alkane, amide carbonyl, nitro, and amine groups could combine intensively with the colored compounds in POME. This is the first reported work on the application of A. fumigatus for the decolorization of POME. The present investigation suggested that growing cultures of A. fumigatus has potential applications for the decolorization of POME through the biosorption and biodegradation processes.

Optimization of decolorization of methylene blue by lignin peroxidase enzyme produced from sewage sludge with Phanerocheate chrysosporium

Optimization of decolorization of methylene blue (MB) dye by lignin peroxidase (LiP) enzyme produced by white-rot fungus Phanerochaete chrysosporium using sewage treatment plant (STP) sludge as a major substrate was carried out in the laboratory. Optimization by the one-factor-at-a-time (OFAT) and statistical approach was carried out to determine the process conditions on optimum decolorization of MB dye using LiP enzyme in static mode. The OFAT method indicated that the optimum conditions for decolorization of MB dye (removal: 14–40%) was at temperature 55 °C, pH 5.0 with hydrogen peroxide (H 2O 2) concentration 4.0 mM, MB dye concentration 20 mg/L and LiP activity 0.487 U/ml. The addition of veratryl alcohol to the reaction mixtures did not contribute any further increases in decolorization. The initial concentration of MB and the activity of LiP enzyme were further optimized using response surface methodology (RSM). The contour and surface plots suggested that the optimum initial concentration of MB and LiP activity predicted were 15 mg/L and 0.687 U/ml, respectively for the removal of 65%. The validation of the model showed that the decolorization process gave the higher removal of 90% in agitation mode compared to the static mode with 65% for 60 min of incubation time by LiP enzyme.