Decolourization Percentage Research Articles

Decolourization potential of white-rot fungus Phanerochaete chrysosporium on synthetic dye bath effluent containing Amido black 10B

Synthetic azo dyes are extensively used in textile industry and are not easily degraded into the environment due to their complex structure. Due to the low degree of fixation of these dyes to fabrics, more than 10–15% of the dye does not bind to fabrics during colour processing and release into water bodies as effluent cause serious environmental pollution. White-rot fungus is found to be capable of degrading lignin which has a complex structure similar to azo dyes. In this study, the decolourization potential of white-rot fungus Phanerochaete chrysosporium, which is capable of decolourizing synthetic dye bath effluent, was investigated. Maximum decolourization of 98% was achieved on the third day under normal conditions. The rate of decolourization carried out at different concentrations revealed that the increase in dye effluent concentration suppresses the percentage decolourization. The optimized amounts of nutrients were found to be 0.5%, 0.1% and 0.5% of glucose, manganese sulphate and ammonium salts, respectively. The addition of inducers such as starch and lignin increased enzyme production and the rate of decolourization.

Biodegradation pathway and detoxification of the diazo dye Reactive Black 5 by Phanerochaete chrysosporium

The in vivo biodegradation of the diazo dye Reactive Black 5 (RB5) by Phanerochaete chrysosporium immobilised on cubes of nylon sponge and on sunflower-seed shells (SS) in laboratory-scale bioreactors was investigated. The SS cultivation led to the best results with a decolouration percentage of 90.3% in 72h for an initial RB5 concentration of 100mg/L. It was found that the addition of 0.4mM veratryl alcohol (VA) into the medium considerably increased the decolouration rate in SS cultivation. However, the addition of VA had no effect in the nylon cultivation. Thin layer chromatography (TLC) revealed that RB5 was transformed into one metabolite after 24h. UV–vis spectroscopy and Fourier Transform Infrared (FT-IR) also confirmed the biodegradation of RB5. Toxicity of RB5 solutions before and after fungal treatment was assayed using Sinorhizobium meliloti as a sensitive soil microorganism. P. chrysosporium transformed the toxic dye RB5 into a non-toxic product.

Production of laccase and decolouration of the textile dye Remazol Brilliant Blue R in temporary immersion bioreactors

Laccase production by Trametes pubescens grown on sunflower-seed shells (SS) under solid-state fermentation (SFF) conditions in temporary immersion bioreactors was studied. Three immersion cycles were considered: 1 min immersed and 9 min non-immersed, 1 min immersed and 30 min non-immersed and 1 min immersed and 60 min non-immersed. The latter led to the highest laccase activities (4000–6000 U l −1). Also, the in vitro and in vivo decolouration of the recalcitrant textile dye Remazol Brilliant Blue R (RBBR) was assessed. It was found that RBBR (133.33 mg l −1) was efficiently decolourised by T. pubencens grown on SS under SSF conditions in temporary immersion bioreactors in five successive batches. The percentage of RBBR decolouration was higher than 55% in 4 h and around 70% in 24 h in all the batches. However, it was found that RBBR decolouration by the crude culture filtrates was more advantageous. Thus, an RBBR decolouration percentage of nearly 80% in 2 h was obtained.

Immobilization of commercial laccase onto green coconut fiber by adsorption and its application for reactive textile dyes degradation

► Coconut fiber was successfully used to immobilize commercial laccase by adsorption. ► The immobilization improved the operational and thermal stabilities of free enzyme. ► A high decolourization of practically all reactive textile dyes studied was obtained. An effort has been made to find a cheaper, easily available and simple alternative for the immobilization of enzymes and subsequent utilization at large scale in textile wastewater treatment. Commercial laccase was immobilized for the first time on an agroindustrial residue, green coconut fiber, by physical adsorption. The effect of the immobilization conditions (enzyme concentration, contact time and pH value) on the properties of the biocatalyst was determined. Then, the immobilized enzyme characterization was performed and kinetic parameters were obtained. Thermal and operational stabilities were improved compared with free commercial laccase showing its potential for continuous applications. Finally, the performance of immobilized laccase for the continuous degradation of various reactive textile dyes and of a mixture of them in batch reactors was evaluated. Two phenomena were observed: decolourization of the solutions due to dyes adsorption on the support and due to the enzyme action. A high decolourization percentage of practically all dyes in the first two cycles and an effective decolourization of the dye mixture were obtained, showing the suitability of the immobilized commercial laccase for continuous colour removal from textile industrial effluents.

Biodegradation of Azo Dyes by Three Isolated Bacterial Strains: An Environmental Bioremedial Approach

The present study was conducted to investigate the decolorization and degradation of azo dyes using bacteria isolated from textile dye effluent. Three different bacterial species were isolated and the isolates were identified as Bacillus subtilis, Pseudomonas aeruginosa, and Psuedomonas putida. The bacterial inoculums were inoculated into flasks containing azo dyes (500 mg/l) with trace amounts of yeast extract, glucose and sucrose and then sterilized and incubated for 4 days. The decolourization was expressed in terms of percentage decolourization. Psuedomonas putida (95%) was identified as the best decolourizer of Blue RR. Pseudomonas aeruginosa (93%) was the best decolourizer of Black B. The best decolourizer of Red RR was Bacillus subtilis (91%). Bacillus subtillis (65%) highly decolourized the Yellow RR. Pseudomonas aeruginosa (70.58%) was the best decolourizer of Navy Blue. The degradation product after decolorization was examined by thin layer chromatography and Fourier transformed infrared spectroscopy analysis.

Gamma Radiolysis Studies of Aqueous Solution of Brilliant Green Dye

The effect of γ–radiation on colour intensity of aqueous solution of Brilliant Green has been investigated at two different concentrations. The degradation of Brilliant Green (BG) has also been investigated in presence of suspended ZnO, by adding different amounts of ZnO. Simultaneously the conductance and pH of each solution system were measured before and after γ‐irradiation. All the γ–irradiations were performed at a dose rate of 0.60 kGyhr-1 in GC‐900. The maximum dose required for the complete degradation of the dye was found to be 0.39 kGy. G(‐dye) values were found to decrease with increase in gamma dose and were in the range 4.26 ‐ 12.81. The conductance (7.6 ‐ 25.3 μS) and pH values increased marginally with dose for both the concentrations. The rate of decolouration was found to be high at lower doses and the efficiency of dye removal was higher at low concentration of the dye. This may be attributed to the presence of reaction by‐products from the destruction of parent compound build up and compete for reaction intermediate species. The rate of reaction and rate constants were calculated and it was found that the degradation reaction follows first order kinetics. It was found that the decolouration percentage was more in dye systems in absence of ZnO.

Transformation pathway of Remazol Brilliant Blue R by immobilised laccase

This study deals with the biotransformation products obtained from the transformation of the anthraquinonic dye Remazol Brilliant Blue R (RBBR) by immobilised laccase from the white-rot fungus Trametes pubescens. A decolouration percentage of 44% was obtained in 42h. RBBR transformation products were investigated using ultraviolet-visible (UV-vis) spectrum scan and High Performance Liquid Chromatography/Mass Spectrometry (LC-MS) analysis. Two compounds were identified as the transformation intermediates (m/z 304.29 and m/z 342.24) and other two as the final transformation products (m/z 343.29 and m/z 207.16). As a result a metabolic pathway for RBBR transformation by laccase was proposed. No backward polymerisation of the transformation products resulting in recurrent colouration was observed after laccase treatment of RBBR. It was also found that the biotransformation products of RBBR showed less phytotoxicity than the dye itself.

Industrial dye degradation and detoxification by basidiomycetes belonging to different eco-physiological groups

Twenty-five basidiomycetes belonging to 17 species and ascribable to different eco-physiological groups were screened for their ability to decolorize 9 commercially important industrial dyes comprising a variety of anthraquinonic, azoic and phtalocyanin chromophores. The influence of the culture medium, particularly its C:N ratio, on decolourisation capacity was considered on solid substrate. Three strains of Bjerkandera adusta performed the highest decolourisation yields being able to degrade all dyes on all media and to produce a wide spectrum of oxidative enzyme activities. Hence, B. adusta strains were selected for further experiments in liquid cultures together with other 6 fungi that resulted effective in the decolourisation of the largest number of molecules in the broadest spectrum of cultural conditions. Particularly B. adusta MUT 3060 was found very effective (decolourisation percentage over 90%) in the treatment of simulated effluents composed of single and mixed dyes at high concentration (1000 mg/l). Peroxidase activity dependent (up to 362 U/l) and independent from manganese (up to 57 U/l) were detected during the decolourisation process. The Lemna minor toxicity test showed a significant reduction of toxicity after the fungal treatment indicating that decolourisation corresponded to an actual detoxification of the wastewater.

Laccase and polyphenol oxidase activities of marine cyanobacteria: a study with Poly R-478 decolourization

The various marine cyanobacterial strains tested showed wide variation in growth patterns and decolourization patterns of the lignin model polymeric dye Poly R-478. The study revealed the presence of laccases (LACs) and polyphenol oxidases (PPOs) in marine cyanobacteria. All the ten tested strains were found to possess constitutive PPOs, whereas only four strains showed the presence of constitutive laccases. Within 7 days of incubation the highest percentage of decolourization was shown by Phormidium valderianum BDU140441 (65%), and Oscillatoria chlorina BDU 140691 (12%) showed the least. Isoforms of LACs were found to be induced by the laccase elicitors veratryl aldehyde, caffeic acid, guaiacol and tannic acid. Cyanobacterial strains that possess both LACs and PPOs were relatively more efficient in decolourizing the dye. Altering the concentrations of nitrogen, phosphorus, potassium and sulphur from the basal medium influenced the efficiency of dye decolourization.

Triphenylmethanes, malachite green and crystal violet dyes decolourisation bySphingomonas paucimobilis

In this study, Gram negative bacterium,Sphingomonas paucimobilis, was used to test its ability to decolourise two triphenylmethane dyes: malachite green (MG) and crystal violet (CV) in mineral salts medium (MSM). Decolourisation was examined with dye concentrations (2.5, 5, 15, 25, 30 and 50 mg/l), glucose (0, 1.4, 2.8, 4.2, 5.6 and 7 mM) and yeast extract concentrations (0, 0.05, 0.10, 0.15% w/v). Our results showed thatSphingomonas paucimobilis used at 1 OD (λ 600 nm), equivalent to 14×107 CFU/ml cell concentration, remove MG and CV colour with 35 and 55%, respectively, for 2.5 mg/l dye concentration in MSM. The best removal efficiencies for decolourisation were 93.43% for MG and 71.29% for CV at 50 mg/l dye concentration, obtained with 7 mM of glucose used as source of carbon. Whereas the optimum concentration of yeast extract which allowed high value on decolourisation was determined at 0.1% for MG and 0.05% for CV. We obtained the high percentage of decolourisation which reaches 100% within 10 h. Moreover, at the same conditions the source of nitrogen yeast extract enhanced more rapidly the decolourisation of dyes colour removal by a new natural isolatesSphingomonas paucimobilis which was significantly affected by adding nutrient sources.

Solar photoassisted advanced oxidation process of azo dyes

Advanced oxidation processes assisted with natural solar radiation in CPC type reactors (parabolic collector compound), was applied for the degradation of three azo dyes: acid orange (AO7), acid red 151 (AR151) and acid blue 113 (AB113). Fenton, Fenton like and ferrioxalate-type complexes showed to be effective for degrade the azo linkage and moieties in different extensions. Initially, the best dose of reagents (Fe(3 + )-H(2)O(2)) was determined through a factorial experimental design, next, using response surface methodologies, the reagent consumption was reduced up to 40%, maintaining in all cases high decolourisation percentages (>98%) after 60 min. of phototreatment. In this work, it was also studied the effect of concentration changes of the influent between 100-300 mg/L and the operation of the photocatalytic process near neutral conditions (pH 6.0-6.5) by using ferrioxalate type complex (FeOx).

Microaerophilic–aerobic sequential decolourization/biodegradation of textile azo dyes by a facultative Klebsiella sp. strain VN-31

Four different azo dyes were decolourized and biodegraded in a sequential microaerophilic–aerobic treatment by a facultative Klebsiella sp. strain VN-31, a bacterium isolated from activated sludge process of the textile industry. Dye decolourization was performed under microaerophilic conditions until no colour was observed (decolourization percentage >94%). The medium was then aerated to promote the biodegradation of the amines produced. The presence of aromatic amine in the microaerophilic stage and its absence in the aerobic stage demonstrate azo bond reduction and an oxidative biodegradation process, respectively. Total Organic Carbon (TOC) reduction for the growth medium plus dyes was ∼50% in the microaerophilic stage and ∼80% in the aerobic stage. The degradation products were also characterized by FT-IR and UV–vis techniques and their toxicity measured using Daphnia magna. The results provide evidence that the successive microaerophilic/aerobic stages, using a single Klebsiella sp. strain VN-31 in the same bioreactor, were able to form aromatic amines by the reductive break down of the azo bond and to oxidize them into non-toxic metabolites.

Biodegradation of textile azo dyes by a facultative Staphylococcus arlettae strain VN-11 using a sequential microaerophilic/aerobic process

A facultative Staphylococcus arlettae bacterium, isolated from an activated sludge process in a textile industry, was able to successfully decolourize four different azo dyes under microaerophilic conditions (decolourization percentage >97%). Further aeration of the decolourized effluent was performed to promote oxidation of the degradation products. The degradation products were characterized by FT-IR and UV–vis techniques and their toxicity with respect to Daphnia magna was measured. The amine concentrations as well as the total organic carbon (TOC) levels were monitored during the biodegradation process. The presence of aromatic amine in the microaerophilic stage and its absence in the aerobic stage indicated the presence of azoreductase activity and an oxidative biodegradation process, respectively. TOC reduction was ∼15% in the microaerophilic stage and ∼70% in the aerobic stage. The results provided evidence that, using a single Staphylococcus arlettae strain in the same bioreactor, the sequential microaerophilic/aerobic stages were able to form aromatic amines by reductive break-down of the azo bond and to oxidize them into non-toxic metabolites.

Production of laccase and manganese peroxidase by white-rot fungi from sugarcane bagasse in solid bed: Use for dyes decolourisation

Three strains of white-rot fungi were tested in solid state fermentation and submerged culture to obtain enzymes for dyes biotransformation. Both sugarcane bagasse and dyes induced laccase and manganese peroxidase biosynthesis but laccase seems to be the main enzyme related to the decolourisation profiles. A variable behavior of strains was observed depending on inducers, fermentation system and characteristics of the strains. Crude enzyme of Earliella scabrosa obtained in solid state fermentation showed higher decolourisation percentage of Navy FNB and Red FN-3G dyes than Trametes maxima (13) and Ganoderma zonatum (B-18). T. maxima exhibited the best decolourisation percentage in submerged cultures supplemented with Navy FNB, Red FN- 3G and yellow P-6GS dyes. Growing biomass of T. maxima could supply other enzymes and mediators for dyes transformation. Peculiar behaviour was observed with Ganoderma zonatum (B-18), it had a similar dyes biodegradation in both liquid and solid bed fermentation and there was not positive correlation between ligninolytic enzymes production and decolourisation pattern. The employment of crude enzymes produced in solid bed of bagasse could be an attractive option for biological removal of textile dyes.

Decolourisation and detoxification of textile effluents by fungal biosorption

Textile effluents, in addition to high COD, display several problems mainly due to toxicity and recalcitrance of dyestuffs. Innovative technologies effective in removing dyes from large volumes of effluents at low cost and in a timely fashion are needed. Fungi are among the most promising organisms for dye biosorption. In this study dye decolourisation, COD and toxicity decrease of three wastewater models after the treatment with inactivated biomasses of three Mucorales fungi cultured on two different media were evaluated. Fungal biomasses displayed good sorption capabilities giving rise to decolourisation percentages up to 94% and decrease in COD up to 58%. The Lemna minor toxicity test showed a significant reduction of toxicity after biosorption treatments, indicating that decolourisation corresponds to an actual detoxification of the treated wastewaters.

Effect of ph and nutrient starvation on biodegradation of azo dyes by Cellulomonas sp.

The effect of pH and some nutrients starvation on biodegradation of azo dyes (Orange II and Direct Blue 71) by Cellulomonas sp. was investigated. Highest percentage decolourization values of 62.85% and 56.23% were obtained at pH 6.5 for Orange II and Direct Blue 71 respectively. Rate of decolourization decreased with increasing concentration of nitrate (sodium nitrate) and sulphate (magnesium sulphate heptahydrate). Highest percentage decolourization (83.75% for Orange II and 76.89% for Direct Blue 71) was obtained in positive controls (no nitrate added). Corresponding values for sulphate-limited conditions were 91.71% for Orange II and 76.25% for Direct Blue 71 in positive controls (no sulphate added). The nitrogen of the generated aromatic amines provided the sole source of nitrogen in positive controls. Desulphonation of the aromatic moiety provided the sole source of sulphur in the positive control medium. The study shows that detoxification of ecosystems contaminated with azo dyes are enhanced under nitrate and sulphate-limited conditions Keywords: Biodegradation, Cellulomonas sp., azo dyes, pH, nitrate, sulphate. AJAZEB Vol. 6 2004: pp. 51-55

Improvement of the catalytic performance of lignin peroxidase in reversed micelles

AbstractBACKGROUND: Anionic surfactant sodium bis (2‐ethylhexyl) sulfosuccinate (AOT) had an inhibiting effect on lignin peroxidase (LiP). To improve the catalytic activity of LiP in an AOT reversed micelle in isooctane, nonionic surfactant polyoxyethylene lauryl ether (Brij30) was incorporated into the interfacial membrane. H2O2 played dual roles in the LiP‐catalyzed oxidation of substrates. To obtain a sustainable high activity of LiP, a coupled enzymatic reaction, i.e. the glucose oxidase (GOD)‐catalyzed oxidation of glucose was used as an H2O2 source.RESULTS: Owing to modification of the charge density of the interfacial membrane, the activity of LiP in an optimized AOT/Brij30 reversed micellar medium (χB (the molar percentage of Brij30) = 0.53, ω0 ([H2O]/([AOT] + [Brij30]) = 23, pH = 4.8) was 40 times that in a single AOT reversed micelle. Due to the controlled release of H2O2, the concentration of H2O2 in the mixed reversed micellar medium was maintained at a moderately high level throughout, which made the LiP‐catalyzed oxidation of substrates proceed at a higher conversion rate than counterparts in which H2O2 was supplied externally in one batch at the beginning of the reaction. Decolourization of two waterless‐soluble aromatic dyes (pyrogallol red and bromopyrogallol red) using LiP coupled with GOD in the medium also demonstrated that a higher decolourization percentage was obtained if H2O2 was supplied enzymatically.CONCLUSION: The proposed measures (both physicochemical and biochemical) were very effective, giving significant improvement in the catalytic performance of LiP in a single AOT reversed micelle in isooctane, which helped to degrade or transform hydrophobic aromatic compounds with LiP in reversed micelles more efficiently. Copyright © 2007 Society of Chemical Industry

Biosorption of simulated dyed effluents by inactivated fungal biomasses

Treatment of dyed effluents presents several problems mainly due to the toxicity and recalcitrance of dyestuffs. Innovative technologies, such as biosorption, are needed as alternatives to conventional methods to find inexpensive ways of removing dyes from large volumes of effluents. Inactivated biomasses do not require a continuous supply of nutrients and are not sensitive to the toxicity of dyes or toxic wastes. They can also be regenerated and reused in many cycles and are both safe and environment-friendly. The sorption capacities (SC) of autoclaved biomasses of three Mucorales fungi ( Cunninghamella elegans, Rhizomucor pusillus and Rhizopus stolonifer), cultured on two different media, were evaluated against simulated effluents containing concentrations of 1000 and 5000 ppm of a single dye and a mix of 10 industrial textile dyes in batch experiments. SC values of up to 532.8 mg of dye g −1 dry weight of biomass were coupled with high effluent decolourisation percentages (up to 100%). These biomasses may thus prove to be extremely powerful candidates for dye biosorption from industrial wastewaters. Even better results were obtained when a column system with the immobilised and inactivated biomass of one fungus was employed.

Decolouration of industrial azo dyes by crude laccase from Trametes hirsuta

The decolouration of several azo dyes, commonly used in the leather industry, by crude laccase obtained from Trametes hirsuta cultivation was assessed. Among the six dyes studied four showed a decolouration percentage higher than 50% in 4 h, whereas the other two showed more resistance to degradation. These results show the ability of laccase towards different dye structures as well as its enormous potential for the decolouration of recalcitrant azo dyes.

The effect of HRT on the decolourisation of the Grey Lanaset G textile dye by Trametes versicolor

Abstract The establishment of the operational conditions for the continuous treatment process of the metal complex dye Grey Lanaset G (150 mg l−1), in a fluidised bed bioreactor using air pulses with retained pellets of the white rot fungus Trametes versicolor has been carried out. Although the bioreactor operated under non-growth conditions, the fungus activity related to laccase production was maintained. The glucose consumption rate used to maintain the fungus was evaluated in 0.31 ± 0.03 g glucose d−1 DCW−1. The effect of the hydraulic retention time (HRT) on the decolourisation yield was also studied. Decolourisation was highly efficient (>80%) for the different HRTs ranging from 18 to 120 h, and the dye removal rates ranged from 6.73 to 1.16 mg l−1 h−1. No direct relationship between decolourisation and extracellular enzyme activity was found, and high enzyme activities were not necessary to obtain high decolourisation percentages. The treated effluent fulfils the environmental quality standards in relation to colour, so it could be discharged into a municipal wastewater treatment plant if necessary.