Bioremediation Of Dyes Research Articles

Enzymatic hydrolysis and characterization of waste lignocellulosic biomass produced after dye bioremediation under solid state fermentation

Sugarcane bagasse (SCB) adsorbes 60% Reactive Blue172 (RB172). Providensia staurti EbtSPG able to decolorize SCB adsorbed RB172 up to 99% under solid state fermentation (SSF). The enzymatic saccharification efficiency of waste biomass after bioremediation of RB172 process (ddSCB) has been evaluated. The cellulolyitc crude enzyme produced by Phanerochaete chrysosporium used for enzymatic hydrolysis of native SCB and ddSCB which produces 0.08 and 0.3g/L of reducing sugars respectively after 48h of incubation. The production of hexose and pentose sugars during hydrolysis was confirmed by HPTLC. The effect of enzymatic hydrolysis on SCB and ddSCB has been evaluated by FTIR, XRD and SEM analysis. Thus, during dye biodegradation under SSF causes biological pretreatment of SCB which significantly enhanced its enzymatic saccharification. Adsorption of dye on SCB, its bioremediation under SSF produces wastes biomass and which further utilized for enzymatic saccharification for biofuel production.

Rapid decolorization of methyl orange by a novel Aeromonas sp. strain DH-6.

Azo dyes are extensively used, but are recalcitrant and refractory. In this study, an indigenous strain DH-6 was isolated and identified as Aeromonas sp. based on 16S rDNA analysis for its excellent methyl orange (MO) decolorizing capability. Plackett-Burman design and response surface methodology (RSM) were employed to investigate the effect of operational parameters on decolorization and to optimize the decolorization process. Based on the results the concentrations of glucose, Na2HPO4 and MO and temperature were selected as the four significant parameters of RSM. The optimal conditions for MO decolorization by the strain were as follows: 3.0 g/L glucose, 4.9 g/L Na2HPO4, 100 mg/L MO, and at 40 °C. The verification tests showed that 95.5% decolorization was observed after incubation for 2 h, which is within the confidence interval. Under the optimal conditions, the kinetics of the decolorization fitted the first-order model well (R(2) = 0.969). As the strain DH-6 still showed a good decolorizing capability at a relatively high temperature, it is considered a candidate for azo dye bioremediation in some tropical or subtropical regions.

Exploiting the potential of plant growth promoting bacteria in decolorization of dye Disperse Red 73 adsorbed on milled sugarcane bagasse under solid state fermentation

Bioremediation of textile dyes adsorbed on agricultural solid wastes under solid state fermentation (SSF) using rhizospheric plant growth promoting microorganisms pose an ecofriendly, economically feasible and promising treatment approach. The purpose of this study was to adsorb azo dye Disperse Red 73 (DR73) on sugarcane bagasse (SCB) and its further bioremediation using consortium-RARB under SSF. The particle size of SCB 0.002 mm showed maximum adsorption (65%) for DR73. Kinetics of adsorption of DR73 on milled SCB follows pseudo-second order kinetics. The individual cultures of Rhodobacter erythropholis MTCC 4688, Azotobacter vinelandii MTCC 1241, Rhizobium meliloti NCIM 2757 and Bacillus megaterium NCIM 2054 showed 44, 28, 50 and 61% decolorization of DR73 in 48 h respectively; while the consortium-RARB showed complete decolorization in 48 h. Optimum moisture content, temperature and pH for decolorization of DR73 was found to be 90%, 30 °C and 6 respectively. DR73 biodegradation analysis was carried out using HPTLC, FTIR and HPLC. Phytotoxicity and genotoxicity studies revealed detoxification of DR73. Tray bioreactor study for decolorization of adsorbed DR73 on SCB suggests its implementations at large scale. Use of plant growth promoting bacteria's consortium under SSF for bioremediation of adsorbed dyes gives a novel ecologically sustainable approach.

Optimization of growth media for enhanced production of laccase by Cryptococcus albidus and its application for bioremediation of chemicals

Cryptococcus albidus , isolated from the sediments of Century Pulp and Paper Mill, Lalkuan, Nainital, Uttarakhand, India, produced a copper containing oxidase, laccase, that was capable of degrading environmental pollutants. Bagasse was the most efficient inducer for laccase production. The Taguchi approach was used to optimize the growth media for five factors, i.e., pH, copper sulphate, carbon, nitrogen, and the inducer at four levels using an M-16 orthogonal array. The optimum conditions for laccase production were pH (6), CuSO4 (2 mmol/L), meat peptone (0·5%), glucose (0·1%), and bagasse (1·0%). After optimization, laccase production increased seven times from 32 to 219 IU/mg. The inducer (bagasse) had maximum effect on laccase production leading to 52% increase, while pH had minimum effect with 7% increase. Growth media with laccase activity (2 U/mL) was applied for the bioremediation of dyes, effluent, and chemical compounds. These experiments showed that the growth media with laccase activity (2 U/mL) produced by Cryptococcus albidus had good potential for bioremediation of toxic and recalcitrant compounds. Further, the laccase enzyme extracted from the growth media was fractionated by DEAE-cellulose ion-exchange chromatography, and the molecular weight of the enzyme determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS – PAGE) was found to be 64 kDa. The activity of laccase was confirmed by native PAGE, in which ABTS was used for staining gel.

Production of laccase from newly isolated Pseudomonas putida and its application in bioremediation of synthetic dyes and industrial effluents

Abstract A novel laccase enzyme producing bacterium, Pseudomonas putida MTCC 7525, was isolated and subjected to optimization of laccase production. Maximum production (94.10 U/ml) was achieved at 30 °C and pH 8 (108 h incubation) with 10% skim milk and 1 mM sodium nitrate as additional nitrogen source. The laccase was purified by salt precipitation followed by ion exchange chromatography which showed 6.44 fold purification. The purified enzyme had optimal activity at pH 8.0 and 40 °C, and showed stability in DMSO retaining more than 85% of original activity. In presence of manganese and cadmium, enzyme retained >95% and 92% activity, respectively. The molecular weight of laccases was 39.5 kDa and activity was inhibited by pCMB (93%). The synthetic dyes (0.02%) and industrial effluents (10%) were decolorized to 74–93 and 58–68%, respectively when treated with culture of P. putida . However, the culture supernatant of P. putida showed about 36–94 and 16–86% decolorization of synthetic dyes and effluents, respectively within 24 h of incubation.

Decolorization of chemically different dyes by white-rot fungi in submerged cultures

Forty-two white-rot fungi in submerged cultures were tested to determine their dye decolorization capacity and the optimal conditions for the decolorization process. Trametes pubescens Cui 7571 was found to be the most effective strain in terms of decolorization performance on the azo dye Congo Red, and it exhibited excellent reusability as well as persistence in sequential decolorization experiments. Optimization of the decoloration process was also conducted to evaluate the effects of a number of chemical compounds, metal salts, inducers, and mediators on the dye decolorization rate. On the seventh day, a highest dye removal of 98.83 % was observed with addition of copper at 2.5 mmol L−1, Tween 80 at 1.0 % (v/v), and ferulic acid at 0.50 μmol L−1, respectively. The adsorption of mycelia to dyes was not a significant contributor to dye removal, and decolorization by the functional fungus T. pubescens depended on biodegradation by enzymes, as evidenced by the results of the moist heat sterilization treatment (121°C for 20 min), induction of extracellular enzymes, and scanning electron microscopy. Four dye degradation metabolites, i.e., naphthalene amine, biphenyl amine, biphenyl ,and naphthalene diazonium, were identified by Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry. The phytotoxicity tests indicated that degraded metabolites had almost a negligible effect on the plant seeds as compared to that of dye, which is indicative of the less toxic nature of the metabolites. Our results suggest that white-rot fungus T. pubescens could be developed into a novel azo dye bioremediation strategy.

Acid Dye Biodegradation Using Saccharomyces cerevisiae Immobilized with Polyethyleneimine-Treated Sugarcane Bagasse

Chemical reagents used by the textile industry are very diverse in their composition, ranging from inorganic compounds to polymeric compounds. Strong color is the most notable characteristic of textile effluents, and a large number of processes have been employed for color removal. In recent years, attention has been directed toward various natural solid materials that are able to remove pollutants from contaminated water at low cost, such as sugarcane bagasse. Cell immobilization has emerged as an alternative that offers many advantages in the biodegradation process, including the reuse of immobilized cells and high mechanical strength, which enables metabolic processes to occur under adverse conditions of pH, sterility, and agitation. Support treatment also increases the number of charges on the surface, thereby facilitating cell immobilization processes through adsorption and ionic bonds. Polyethyleneimine (PEI) is a polycationic compound known to have a positive effect on enzyme activity and stability. The aim of the present study was to investigate a low-cost alternative for the biodegradation and bioremediation of textile dyes, analyzing Saccharomyces cerevisiae immobilization in activated bagasse for the promotion of Acid Black 48 dye biodegradation in an aqueous solution. A 1 % concentration of a S. cerevisiae suspension was evaluated to determine cell immobilization rates. Once immobilization was established, biodegradation assays with free and immobilized yeast in PEI-treated sugarcane bagasse were evaluated for 240 h using UV–vis spectrophotometry. The analysis revealed significant relative absorbance values, indicating the occurrence of biodegradation in both treatments. Therefore, S. cerevisiae immobilized in sugarcane bagasse is very attractive for use in biodegradation processes for the treatment of textile effluents.

Phytoremediation of triphenylmethane dyes by overexpressing a Citrobacter sp. triphenylmethane reductase in transgenic Arabidopsis

Triphenylmethane dyes are extensively utilized in textile industries, medicinal products, biological stains, and food processing industries, etc. They are generally considered as xenobiotic compounds, which are very recalcitrant to biodegradation. The widespread persistence of such compounds has generated concerns with regard to remediation of them because of their potential carcinogenicity, teratogenicity, and mutagenicity. In this study, we present a system of phytoremediation by Arabidopsis plants developed on the basis of overexpression of triphenylmethane reductase (TMR) from the Citrobacter sp. The morphology and growth of TMR transgenic Arabidopsis plants showed significantly enhanced tolerances to crystal violet (CV) and malachite green (MG). Further, HPLC and HPLC-MS analyses of samples before and after dye decolorization in culture media revealed that TMR transgenic plants exhibited strikingly higher capabilities of removing CV from their media and high efficiencies of converting CV to non-toxic leucocrystal violet (LCV). This work indicates that microbial degradative gene may be transgenically exploited in plants for bioremediation of triphenylmethane dyes in the environment.

Bioremediation of direct dyes in simulated textile effluents by a paramorphogenic form of Aspergillus oryzae

Azo dyes are extensively used for coloring textiles, paper, food, leather, drinks, pharmaceutical products, cosmetics and inks. The textile industry consumes the largest amount of azo dyes, and it is estimated that approximately 10-15% of dyes used for coloring textiles may be lost in waste streams. Almost all azo dyes are synthetic and resist biodegradation, however, they can readily be reduced by a number of chemical and biological reducing systems. Biological treatment has advantages over physical and chemical methods due to lower costs and minimal environmental effect. This research focuses on the utilization of Aspergillus oryzae to remove some types of azo dyes from aqueous solutions. The fungus, physically induced in its paramorphogenic form (called 'pellets'), was used in the dye biosorption studies with both non-autoclaved and autoclaved hyphae, at different pH values. The goals were the removal of dyes by biosorption and the decrease of their toxicity. The dyes used were Direct Red 23 and Direct Violet 51. Their spectral stability (325-700 nm) was analyzed at different pH values (2.50, 4.50 and 6.50). The best biosorptive pH value and the toxicity limit, (which is given by the lethal concentration (LC(100)), were then determined. Each dye showed the same spectrum at different pH values. The best biosorptive pH was 2.50, for both non- autoclaved and autoclaved hyphae of A. oryzae. The toxicity level of the dyes was determined using the Trimmed Spearman-Karber Method, with Daphnia similis in all bioassays. The Direct Violet 51 (LC(100) 400 mg · mL(-1)) was found to be the most toxic dye, followed by the Direct Red 23 (LC(100) 900 mg · mL(-1)). The toxicity bioassays for each dye have shown that it is possible to decrease the toxicity level to zero by adding a small quantity of biomass from A. oryzae in its paramorphogenic form. The autoclaved biomass had a higher biosorptive capacity for the dye than the non-autoclaved biomass. The results show that bioremediation occurs with A. oryzae in its paramorphogenic form, and it can be used as a biosorptive substrate for treatment of industrial waste water containing azo dyes.

Decolorization of Mordant Orange-1 by <i>Marinobacter algicola MO-17</i>

Problem statement: The textile industries use different types of dyes in their processing units which are liberated in natural marine water bodies. This release of dyes in turn affect the marine flora and fauna very adversely. Approach: The release of textile dyes into the environment is a matter of concern due to the toxicity, mutagenicity, carcinogenicity and xenobiotic nature. Hence, considerable attention has been given in determining the ability of marine microorganism in decolorization and degradation of textile dyes. Results: The present study deals with the decolorization of Mordant Orange-1 was carried out using the acclimatized Marinobacter algicola MO-17 isolated from natural marine environment. The acclimatized strain was capable of decolorizing 800 ?g mL-1 of the dye at high salt concentration (12%) in 24 h. The percent decolorization of the dye was moderated by spectroscopy at 385 nm (?max). Conclusion/Recommendations: The spectrophotometric analysis showed 78.78% decolorization in Nutrient Broth and 76.78% decolorization in Half Strength Nutrient Broth. The percent Chemical Oxygen Demand (COD) reduction of the dye by the strain was 90%. From the study performed, we conclude that, this acclimatized strain can prove better option for bioremediation of textile dyes in wastes containing high salts and in marine environment.

Exploring decolorization and halotolerance characteristics by indigenous acclimatized bacteria: Chemical structure of azo dyes and dose–response assessment

To consider the feasibility of dye bioremediation in salty wastewater, this first-attempt study explored dye decolorization and halotolerance characteristics of indigenous acclimatized bacteria. We tended to consider the aspects in chemical structure of azo dye and toxicity assessment to investigate salt-bearing dye wastewater treatment. Meanwhile, the relationship between the chemical structure and biodegradability of the azo dye was disclosed. The dose–response analysis also quantitatively disclosed salt tolerance of indigenous decolorizers Staphylococcus gallinarum NIU-K1, Exiguobacterium acetylicum NIU-K2, and Exiguobacterium indicum NIU-K4. Plus, the strain NIU-K1 ranked the highest tolerance of all strains. Apparently, bacterial decolorization performance in normal and relatively salty cultures strongly affected by the chemical structure of azo dyes. When the electrophilicity of azo bonds increased and/or the steric hindrance near azo bonds became less significant, azo dye decolorization was more favorable. Plus, the ranking of the maximal specific decolorization rate of RBk5 was NIU-K2 > NIU-K4 > P11≅NIU-K1 at 60 g/L NaCl-containing cultures. Strains NIU-K2 and NIU-K4 were thus more appropriate to be decolorizers for salt-containing wastewater decolorization. This promising result suggested that the application of our acclimatization strategy to select azo dye decolorizers through natural seawater for salt-bearing dye wastewater treatment was feasible with consideration of dose–response assessment.

Up-flow immobilized fungal Column Reactor for the Treatment of Anthraquinone dye Drimarene blue K sub>2 RL

This research work is on the decolorization of a reactive anthraquinone dye Drimarene blue (Db) K2RL, which is known for its markedly usage in textile industry. Due to poor adsorbability to textile fiber, it has a higher exhaustion rate in wastewater. The main objective of our research work was to evaluate the potential of an Up-flow Column reactor (UFCR) (13x1.7//) containing the fungal strain, Aspergillus niger SA1 (immobilized on support material Scotch-BriteTM) for the decolorization of a dye, Db K2RL, in simulated textile effluent. Different concentrations of dye in the effluent were treated in the reactor for 24 h, with a flow rate of 10 mL-1 at hydraulic retention time (HRT) of 10 h. Using anoxic UFCR, decolorization of the effluent was observed maximum, that is, 94.26% at 10 ppm of dye; however, it reduced to 58.51% at 300 ppm of dye. A trend towards increase (
15%) in decolorization of effluent was noted, when the effluent was aerated prior to treatment. Recycling of the effluent containing dye increased the decolorization (85% at 130 ppm of dye; 66% at 500 ppm of dye), however, further recycling decreased the rate of decolorization, which might be due to desorption by the immobilized fungus. The results of these findings providing important insights into the development of effective treatment technology for bioremediation of textile dyes.

Degradation analysis of Reactive Red 198 by hairy roots of Tagetes patula L. (Marigold)

Tagetes patula L. (Marigold) hairy roots were selected among few hairy root cultures from other plants tested for the decolorization of Reactive Red 198. Hairy roots of Tagetes were able to remove dye concentrations up to 110 mg L(-l) and could be successively used at least for five consecutive decolorization cycles. The hairy roots of Tagetes decolorized six different dyes, viz. Golden Yellow HER, Methyl Orange, Orange M2RL, Navy Blue HE2R, Reactive Red M5B and Reactive Red 198. Significant induction of the activity of biotransformation enzymes indicated their crucial role in the dye metabolism. UV-vis spectroscopy, HPLC and FTIR spectroscopy analyses confirmed the degradation of Reactive Red 198. A possible pathway for the biodegradation of Reactive Red 198 has been proposed with the help of GC-MS and metabolites identified as 2-aminonaphthol, p-aminovinylsulfone ethyl disulfate and 1-aminotriazine, 3-pyridine sulfonic acid. The phytotoxicity study demonstrated the non-toxic nature of the extracted metabolites. The use of such hairy root cultures with a high ability for bioremediation of dyes is discussed.

Optimization of growth media for enhanced production of laccase byCryptococcus albidusand its application for bioremediation of chemicals A paper submitted to the Journal of Environmental Engineering and Science.

Cryptococcus albidus , isolated from the sediments of Century Pulp and Paper Mill, Lalkuan, Nainital, Uttarakhand, India, produced a copper containing oxidase, laccase, that was capable of degrading environmental pollutants. Bagasse was the most efficient inducer for laccase production. The Taguchi approach was used to optimize the growth media for five factors, i.e., pH, copper sulphate, carbon, nitrogen, and the inducer at four levels using an M-16 orthogonal array. The optimum conditions for laccase production were pH (6), CuSO4(2 mmol/L), meat peptone (0.5%), glucose (0.1%), and bagasse (1.0%). After optimization, laccase production increased seven times from 32 to 219 IU/mg. The inducer (bagasse) had maximum effect on laccase production leading to 52% increase, while pH had minimum effect with 7% increase. Growth media with laccase activity (2 U/mL) was applied for the bioremediation of dyes, effluent, and chemical compounds. These experiments showed that the growth media with laccase activity (2 U/mL) produced by Cryptococcus albidus had good potential for bioremediation of toxic and recalcitrant compounds. Further, the laccase enzyme extracted from the growth media was fractionated by DEAE-cellulose ion-exchange chromatography, and the molecular weight of the enzyme determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE) was found to be 64 kDa. The activity of laccase was confirmed by native PAGE, in which ABTS was used for staining gel.

Efficacy of bacterial consortium-AIE2 for contemporaneous Cr(VI) and azo dye bioremediation in batch and continuous bioreactor systems, monitoring steady-state bacterial dynamics using qPCR assays

Bacterial consortium-AIE2 with a capability of contemporaneous Cr(VI) reduction and azo dye RV5 decolourization was developed from industrial wastewaters by enrichment culture technique. The 16S rRNA gene based molecular analyses revealed that the consortium bacterial community structure consisted of four bacterial strains namely, Alcaligenes sp. DMA, Bacillus sp. DMB, Stenotrophomonas sp. DMS and Enterococcus sp. DME. Cumulative mechanism of Cr(VI) reduction by the consortium was determined using in vitro Cr(VI) reduction assays. Similarly, the complete degradation of Reactive Violet 5 (RV5) dye was confirmed by FTIR spectroscopic analysis. Consortium-AIE2 exhibited simultaneous bioremediation efficiencies of (97.8 +/- 1.4) % and (74.1 +/- 1.2) % in treatment of both 50 mg l(-1) Cr(VI) and RV5 dye concentrations within 48 h of incubation at pH 7 and 37 degrees C in batch systems. Continuous bioreactor systems achieved simultaneous bioremediation efficiencies of (98.4 +/- 1.5) % and (97.5 +/- 1.4) % after the onset of steady-state at 50 mg l(-1) input Cr(VI) and 25 mg l(-1) input RV5 concentrations, respectively, at medium dilution rate (D) of 0.014 h(-1). The 16S rRNA gene copy numbers in the continuous bioreactor as determined by real-time PCR assay indicated that Alcaligenes sp. DMA and Bacillus sp. DMB dominated consortium bacterial community during the active continuous bioremediation process.

Bioremediation of Dyes in Textile Effluents by Aspergillus oryzae

In this study Aspergillus oryzae was utilized to remove azo dyes from aqueous solution. Physically induced in its paramorphogenic form to produce standardized mycelial pellets, the non-autoclaved and autoclaved hyphae biomass was applied to biosorb the reactive dyes Procion Red HE7B (PR-HE7B) and Procion Violet H3R (PV-H3R) at different pH values (2.50, 4.50, and 6.50). The best pH for biosorption was 2.50, though the autoclaved demonstrated a higher biosorption capacity than the non-autoclaved pellets. The toxicity level was determined using the Trimmed Spearman-Karber method with Daphnia similis in all bioassays. The calculated toxicity of PV-H3R (LC100 62.50 microg mL(-1)) was higher than to PR-HE7B (LC100 300.00 microg mL(-1)), and its results brought out that the decrease of toxicity levels to zero might be accomplished by adding small quantities of pelletized A. oryzae to the solutions.

Structural Insight into Bioremediation of Triphenylmethane Dyes by Citrobacter sp. Triphenylmethane Reductase

Triphenylmethane dyes are aromatic xenobiotic compounds that are widely considered to be one of the main culprits of environmental pollution. Triphenylmethane reductase (TMR) from Citrobacter sp. strain KCTC 18061P was initially isolated and biochemically characterized as an enzyme that catalyzes the reduction of triphenylmethane dyes. Information from the primary amino acid sequence suggests that TMR is a dinucleotide-binding motif-containing enzyme; however, no other functional clues can be derived from sequence analysis. We present the crystal structure of TMR in complex with NADP+ at 2.0-angstroms resolution. Despite limited sequence similarity, the enzyme shows remarkable structural similarity to short-chain dehydrogenase/reductase (SDR) family proteins. Functional assignments revealed that TMR has features of both classic and extended SDR family members and does not contain a conserved active site. Thus, it constitutes a novel class of SDR family proteins. On the basis of simulated molecular docking using the substrate malachite green and the TMR/NADP+ crystal structure, together with site-directed mutagenesis, we have elucidated a potential molecular mechanism for triphenylmethane dye reduction.

Aeration as a factor in textile dye bioremoval by Aspergillus niger

Experiments were done to study the bioremoval/ biosorption of dis-azo dye byAspergillus niger strain 20 in two concentrations using 5 liter bioreactor at five aeration rates. The experimental results are compared for various operating conditions. The dye used was direct brown and the inlet air flow rate was: 1/8, ¼, ½, 1, 2 v/v/min. The aeration rate of ½ v/v/min yielded 9.2 g fungal biomass and removed 72 % of the dye. Increasing of the aeration rate to 2 v/v/min increased the removal to 77%, whereas the biomass was decreased markedly at the end of the incubation time. The results also indicate that the fungal biomass obtained at the three other air flow rates was more or less the same after 3 days of incubation. The obtained results indicate that air flow rates 1/8, ¼ and ½ v/v/min gave better dye bioremoval as compared with the high aeration rate (1, 2 v/v/min) and can be recommended for dis-azo dye bioremediation. Isotherm experiments were conducted to determine the sorbents-desorption behavior of examined dye from aqueous solutions using Langmiur and Freundlich equations. Key words: Textile dyes, removing, dis-azo, batch reactor, modeling, bioremediation.

Microflora involved in textile dye waste removal.

Textile dyes are heavily used in factories for coloring different cloth materials. This work was designed to identify microorganisms capable of removing textile dyes, either by biodegradation or by biosorption. We expected to isolate microorganisms adapted to high dye concentrations from sites near textile industry complex. An experiment was conducted to study the efficiency of the isolates in removing textile dyes. The tested dyes were used as carbon and nitrogen sources for isolation of soil and/or water microorganisms capable of removing textile dyes wastes from factories effluent. The results indicated the low efficiency of both bacteria and actinomycetes in clean-up the effluent from the waste dyes in 10-21 days. On the other hand six fungal isolates were obtained by plating factory effluent on Martin's medium and media containing dyes as the sole source of carbon and nitrogen for growth. These isolates fell in two genera, Aspergillus and Trichoderma. Results of these studies revealed the potential capacity of these fungi to decolorize the tested dyes in comparatively short time (2-24 hours) indicating strong efficiency of dye bioremediation by the fungal isolates. Since the process involved is mostly fast interaction between the fungal mycelium and the dye in the media, the possible mechanism could be based on a biosorption of such chemicals on the intact fungal biomass, rather than direct biodegradation of the compounds.