Biodegradation of C.I. Reactive Red 195 by <Emphasis Type="Italic">Enterococcus faecalis</Emphasis> strain YZ66

Synthetic dyes are extensively used in textile dyeing, paper, printing, colour photography, pharmaceutics, cosmetics and other industries. Among these, azodyes represents the largest and most versatile class of synthetic dyes. As high as 50% of the dyes are released into the environment during manufacture and usage. Traditional methods of treatment are found to be expensive and have operational problems. Biological decolourization has been investigated as a method to transform, degrade or mineralize azo dyes. In the present studies bacteria from soil from dye waste area, dye waste, sewage and dung were subjected to acclimatization with C.I. Reactive Red 195 an azo dye, in the basal nutrient media. The most promising bacterial isolate was used for further dye degradation studies. The 16s rRNA gene sequencing and biochemical characteristics revealed the isolated organism as Enterococcus faecalis strain YZ66. The strain showed 99.5% decolourization of the selected dye (Reactive Red 195–50 mg/l) within one and half hour in static anoxic condition. The optimum pH and temperature for the decolourization was 5.0 and 40°C respectively. The biodegradation was monitored by UV–Vis, FTIR, TLC and HPLC. The final products were characterized by Gas chromatography and Mass Spectrophotometry. Toxicity study demonstrated no toxicity of the biodegradation product. The results suggest that the isolated organism E. faecalis strain YZ 66 can be used as a useful tool to treat waste water containing reactive dyes.     

Optimisation for enhanced decolourization and degradation of Reactive Red BS C.I. 111 by Pseudomonas aeruginosa NGKCTS

Soil samples collected from dye contaminated sites of Vatva, Gujarat, India were studied for the screening and isolation of organisms capable of decolourizing textile dyes. The most efficient isolate, which showed decolourization zone of 48 mm on 300 ppm Reactive Red BS (C.I.111) containing plate, was identified as Pseudomonas aeruginosa. Reactive Red BS (C.I.111) was used as a model dye for the study. The isolated culture exhibited 91% decolourization of 300 ppm dye within 5.5 h over a wide pH range from 5.0 to 10.5 and temperature ranging from 30 to 40°C. The culture was able to decolourize more than 91% of Reactive Red BS under static conditions in presence of either glucose, peptone or yeast extract. Addition of 300 ppm of Reactive Red BS, in each step, in ongoing dye decolourization flask, gave more than 90% decolourization within 2 h corresponding to 136 mg l⁻¹ h⁻¹ dye removal rate. The isolate had the ability to decolourize six different reactive dyes tested as well as the actual dye manufacturing industry’s effluent. The degradation of the dye was confirmed by HPTLC.     

Biodegradation of disperse textile dye Brown 3REL by newly isolated Bacillus sp. VUS

Aims:  To isolate the potential micro-organism for the degradation of textile disperse dye Brown 3 REL and to find out the reaction mechanism.
Methods and Results:  16S rDNA analysis revealed an isolate from textile effluent contaminated soil as Bacillus sp. VUS and was able to degrade (100%) dye Brown 3REL within 8 h at static anoxic condition. A significant increase in the activities of lignin peroxidase, laccase and NADH-DCIP reductase was observed up to complete decolourization of Brown 3REL. The optimum temperature required for degradation was 40°C and pH 6·5–12·0. Phyto-toxicity and chemical oxygen demand revealed nontoxic products of dye degradation. The biodegradation was monitored by UV–VIS, FTIR spectroscopy and HPLC. The final products 6,8-dichloro-quinazoline-4-ol and cyclopentanone were characterized by gas chromatography-mass spectrometry. This Bacillus sp. VUS also decolourized (80%) textile dye effluent within 12 h.
Conclusions:  This study suggests that Bacillus sp. VUS could be a useful tool for textile effluent treatment.
Significance and Impact of the Study:  The newly isolated Bacillus sp. VUS decolourized 16 textile dyes and textile dye effluent also. It achieved complete biodegradation of Brown 3REL. Phytotoxicity study demonstrated no toxicity of the biodegraded products for plants with respect to Triticum aestivum and Sorghum bicolor .     

Biodegradation of reactive textile dye Red BLI by an isolated bacterium Pseudomonas sp. SUK1

A novel bacterial strain capable of decolorizing reactive textile dye Red BLI is isolated from the soil sample collected from contaminated sites of textile industry from Solapur, India. The bacterial isolate was identified as Pseudomonas sp. SUK1 on the basis of 16S rDNA analysis. The Pseudomonas sp. SUK1 decolorized Red BLI (50 mg l(-1)) 99.28% within 1h under static anoxic condition at pH range from 6.5 to 7.0 and 30 degrees C. This strain has ability to decolorize various reactive textile dyes. UV-Vis spectroscopy, FTIR and TLC analysis of samples before and after dye decolorization in culture medium confirmed decolorization of Red BLI. A significant increase in the activities of aminopyrine N-demethylase and NADH-DCIP reductase in cells obtained after decolorization indicates involvement of these enzymes in the decolorization process. Phytotoxicity testing with the seeds of Sorghum vulgare and Phaseolus mungo, showed more sensitivity towards the dye, while the products obtained after dye decolorization does not have any inhibitory effects.     

Decolorization and detoxification of sulphonated azo dye Red HE7B by <Emphasis Type="Italic">Bacillus</Emphasis> sp. VUS

Bacillus sp. VUS decolorized Red HE7B dye (100%) within 18 h in static anoxic conditions. A significant increase in activities of lignin peroxidase, laccase, NADH-DCIP and azo reductase was observed up to complete decolourization of RHE7B. The biodegradation was monitored by UV–Visible spectroscopy (UV–VIS), Fourier Transform Infrared (FTIR) spectroscopy and High Performance Liquid Chromatography (HPLC). The final products 4-methyl-3-(1-sulfo-ethyl)-5-([1,3,5] triazin-2-ylamino)-benzenesulfonic acid; 3-(1-sulfo-ethyl)-5-([1,3,5] triazin-2-ylamino)-benzenesulfonic acid and 3-(1,2-dihydro-[1,3,5] triazin-2-ylamino)-5-sulfomethyl-benzenesulfonic acid were characterized by gas chromatography–mass spectrometry (GC–MS). The phytotoxicity study revealed the non-toxic nature of the generated products with respect to Sorghum bicolor and Triticum aestivum. The metabolites produced after degradation increased the chlorophyll content of crop seedlings. The Ames test revealed the non-mutagenicity and non-carcinogenicity of the degraded products.     

Decolourization of reactive azo dyes with microorganisms growing on soft wood chips

The decolourization of a mixture of 200 mg L⁻¹ each of Reactive Black 5 and Reactive Red 2 dye was studied in batch experiments using microorganisms growing on forest residue wood chips in combination with or without added white-rot fungus, Bjerkandera sp. BOL 13. The study was performed as a first stage in the development of a relatively simple treatment process for textile wastewater, designed to work in developing countries. Forest residue wood chips contain a mixture of fungi and bacteria which is an advantage when complex molecules should be degraded. The wood chips furthermore provide the microorganisms with carbon source which make the addition of e.g. glucose unnecessary. The results showed that the microorganisms growing on the forest residue wood chips decolourized the mixture of the two dyes; adding extra nutrients approximately doubled the decolourization rate. The time needed for decolourization was approximately 18 days when nutrients were added. Lignocellulosic material is complex and so were the analysis, microorganisms were therefore transferred to ordinary soft wood chips from forest residue wood chips. Decolourization was measured with spectrophotometer and in order to determine intermediates HPLC was used.     

Decolourization of textile dye Reactive Violet 5 by a newly isolated bacterial consortium RVM 11.1

Summary Soil samples collected from contaminated sites of Vatva, Gujarat, India were studied for screening and isolation of organisms capable of decolourizing textile dyes. A bacterial consortium RVM 11.1 was selected on the basis of rapid dye decolourization. Reactive Violet 5 (RV 5) was used as model dye. The consortium exhibited 94% decolourization ability within 37 h under a wide pH range from 6.5 to 8.5 and temperature ranging from 25 to 40 °C. The bacterial consortium was able to grow and decolourize RV5 under static conditions in the presence of glucose and yeast extract and also showed an ability to decolourize in the presence of starch in place of glucose. Maximum decolourization efficiency was observed at 200 ppm (mg/l) concentration of RV 5. Bacterial consortium RVM11.1 had the ability to decolourize 10 different dyes tested. The transformation and degradation products after decolourization were examined by HPTLC.     

Efficient decolorization and detoxification of the sulfonated azo dye Reactive Orange 16 and simulated textile wastewater containing Reactive Orange 16 by the white-rot fungus Ganoderma sp. En3 isolated from the forest of Tzu-chin Mountain in China

The sulfonated azo dye Reactive Orange 16 is the commonly used representative of reactive dyes, but is hard to be degraded by some conventional treatment methods. In order to develop more efficient and more cost-effective treatment methods for degrading this recalcitrant dye, the capability of the white-rot fungus Ganoderma sp. En3 isolated by our laboratory to decolorize and detoxify Reactive Orange 16 was investigated in this study. Ganoderma sp. En3 had a strong ability to decolorize high concentrations of Reactive Orange 16 and simulated textile wastewater containing Reactive Orange 16 in submerged cultures. Decolorization of Reactive Orange 16 and its simulated dye effluents by this fungus resulted in the decrease of phytotoxicity. Ganoderma sp. En3 had strong adaptability and tolerance to high concentrations of Reactive Orange 16. Compared with some previous research, Ganoderma sp. En3 was superior to some other fungal strains reported previously in the rate and extent of decolorizing Reactive Orange 16. It was also found that the real textile wastewater could be efficiently decolorized by Ganoderma sp. En3 in submerged cultures. The crude enzyme produced by Ganoderma sp. En3 could also efficiently decolorize Reactive Orange 16 and simulated textile wastewater under in vitro conditions.     

Decolorization of Acid Red 27 and Reactive Red 2 by <Emphasis Type="Italic">Enterococcus faecalis</Emphasis> under a batch system

The objectives of this study were to investigate: (1) the capacity of Enterococcus faecalis on the decolorization of the azo dyes Acid Red 27 and Reactive Red 2; and (2) the growth characteristics of E. faecalis on those dyes. E. faecalis was able to decolorize Acid Red 27 and Reactive Red 2 effectively. High decolorization efficiency (95–100%) was achieved within 3 h of incubation for Acid Red 27, and 12 h for Reactive Red 2, at room temperature, neutral pH, static and non-aerated condition. Growth characteristics of E. faecalis on azo dyes, which were indicated by cell growth rate, biomass production, and growth yield, was worse than the control. E. faecalis grew better on Acid Red 27 rather than Reactive Red 2.     

Biological Decolourization of Textile and Paper Effluents by Pleurotus florida and Agaricus bisporus (White-rot Basidiomycetes)

Summary The extracellular ligninolytic enzymes of white-rot fungi are thought to catalyse the initial steps during the degradation of highly complex compounds like lignin or polycyclic aromatic hydrocarbons. We studied the ability of Pleurotus florida isolated from the foothills of the Western Ghats, India to decolourize the three dyestuffs, Reactive Green, Yellow and Blue, which are widely used in the textile industry around Coimbatore, Tamil Nadu, India. The crude culture filtrate of Pleurotus florida when incubated with different concentrations of dye decolourized it efficiently on the third day. The highest colour removal was found in the case of Reactive Blue. However, when Agaricus bisporus extract was supplemented with Pleurotus florida filtrate, the efficiency increased. The dye decolourization was advanced to the second day and the efficiency of dye decolourization of Reactive Yellow was 89% followed by Reactive Green, which was 45% when a dye concentration of 0.5% was used. Pleurotus florida filtrate alone and in combination with Agaricus bisporus extract reduced the aromatic compounds in textile and paper industry effluents on the first day with >90% efficiency.     

Immobilized laccase for decolourization of Reactive Black 5 dyeing effluent

Reactive Black 5 industrial dyeing effluent was decolourized by free and immobilized laccase. The stability of the enzyme (194 h free and 79 h immobilized) depended on the dyeing liquor composition and the chemical structure of the dye. In the decolourization experiments with immobilized laccase, two phenomenons were observed – decolourization due to adsorption on the support (79%) and dye degradation due to the enzyme action (4%). Dyeing in the enzymatically recycled effluent provided consistency of the colour with both bright and dark dyes.     

Decolourization of azo dyes and a dye industry effluent by a white rot fungus Thelephora sp

A white rot fungus Thelephora sp. was used for decolourization of azo dyes such as orange G (50 microM), congo red (50 microM), and amido black 10B (25 microM). Decolourization using the fungus was 33.3%, 97.1% and 98.8% for orange G, congo red and amido black 10B, respectively. An enzymatic dye decolourization study showed that a maximum of 19% orange G was removed by laccase at 15 U/ml whereas lignin peroxidase (LiP) and manganese dependent peroxidase (MnP) at the same concentration decolourized 13.5% and 10.8%, orange G, respectively. A maximum decolourization of 12.0% and 15.0% for congo red and amido black 10B, respectively, was recorded by laccase. A dye industry effluent was treated by the fungus in batch and continuous modes. A maximum decolourization of 61% was achieved on the third day in the batch mode and a maximum decolourization of 50% was obtained by the seventh day in the continuous mode. These results suggest that the batch mode of treatment using Thelephora sp. may be more effective than the continuous mode for colour removal from dye industry effluents.     

In vitro studies on degradation of synthetic dye mixture by Comamonas sp. VS-MH2 and evaluation of its efficacy using simulated microcosm

Reactive azo dyes are considered as one of the most detrimental pollutants from industrial effluents and therefore their biodegradation is receiving constant scientific consideration. A bacterial isolate VS-MH2, originating from dye contaminated sites of Gujarat, India, was exploited for its ability to degrade a synthetic dye mixture (SDM) (comprising of four azo reactive dyes) under static conditions. The identification of the isolate by 16S rRNA gene sequencing revealed it to be Comamonas sp. The biodegradation of the SDM was analyzed by UV-vis spectroscopy, IR spectroscopy and GC-MS analysis. The isolate showed high metabolic activity towards SDM and degraded it completely (100 mg L(-1)) within 30 h at pH 7 and 35 °C. Simulated microcosm studies in the presence and absence of indigenous microflora confirmed the ability of Comamonas sp. VS-MH2 for dye degradation and to colonize the soil. This is the first investigation reporting the degradation of SDM by Comamonas sp. under simulated soil microcosms.     

Biodegradation of Reactive blue-25 by Aspergillus ochraceus NCIM-1146

The present study dealt with the decolorization and degradation of textile dye Reactive blue-25 (0.1gl(-1)) by mycelium of Aspergillus ochraceus NCIM-1146. Spectrophotometric and visual examinations showed that the decolorization was through fungal adsorption, followed by degradation. Shaking condition was found to be better for complete and faster adsorption (7h) and decolorization (20 days) of dye Reactive blue-25 (100mgl(-1)) as compared to static condition. Presence of glucose in medium showed faster adsorption (4h) and decolorization of dye from bound (7 days) mycelium. FTIR and GCMS analysis study revealed biodegradation of Reactive blue-25 into two metabolites phthalimide and di-isobutyl phthalate.     

Decoloration of textile dyes by Trametes versicolor and its effect on dye toxicity

Amaranth, Tropaeolin O, Reactive Blue 15, Congo Red, and Reactive Black 5 were completely decolorized with no dye sorption by Trametes versicolor. Cibacron Brilliant Red 3G-P, Cibacron Brilliant Yellow 3B-A, and Remazol Brilliant Blue R were partially decolorized with some dye sorbed to the biomass. The Microtox assay before decoloration showed that Amaranth and Tropaeolin O were not toxic [the percent concentration to decrease 20% of the luminescence of Vibrio fischeri (EC₂₀) was greater than 100%]; Cibacron Brilliant Yellow 3B-A, Reactive Blue 15 and Cibacron Brilliant Red 3G-P were moderately non-toxic (100% > EC₂₀ > 75%); Remazol Brilliant Blue R was toxic (75% > EC₂₀ > 50%); and Congo Red and Reactive Black 5 were moderately toxic (50% > EC₂₀ > 25%). After decoloration the toxicity of the solutions containing Amaranth, Tropaeolin O and Reactive Black 5 was unchanged; Reactive Blue 15, Remazol Brilliant Blue R and Cibacron Brilliant Red 3G-P decreased to non-toxic levels; and Cibacron Brilliant Yellow 3B-A and Congo Red became very toxic (EC₂₀ < 25%).     

Malachite green decolourization and detoxification by the laccase from a newly isolated strain of Trametes sp.

The decolourization and detoxification of the triarylmethane dye Malachite green (MG) by laccase from Trametes sp. were investigated. The laccase decolorized efficiently the dye down to 97% of 50 mg L^?1 initial concentration of MG when only 0.1 U mL^?1 of laccase was used in the reaction mixture. The effects of different physicochemical parameters were tested and optimal decolourization rates occurred at pH 6 and at temperatures between 50 and 60 °C. Decolourization of MG occurred in the presence of metal ions which could be found in textile industry effluent. 1-hydroxybenzotriazole (HBT) affected positively the decolourization of MG. The presence of some phenolic compounds namely ferulic, coumaric, gallic, and tannic acids was found to be inhibiting for the decolourization at a concentration of 10 mM.The effect of laccase inhibitors in the decolourization of MG was tested with l-cysteine, and ethylene diamine tetra-acetic acid (EDTA) at concentrations of 0.1, 1 and 10 mM. It was demonstrated that l-cysteine and EDTA inhibited the decolourization starting from 1 mM concentration. However, for NaCl a concentration of 100 mM was needed for the inhibition of laccase. The decolourization of MG resulted in the removal of its toxicity against Phanerochaete chrysosporium.The stability of the laccase toward temperature and HBT free radicals was also assessed during MG decolourization. It was shown that laccase was stable at 50 °C but in the presence of the laccase mediator HBT, the stability of the enzyme was severely affected resulting in a loss of 50% of the activity after 3 h incubation.     

Simple and easy method for the determination of fungal growth and decolourative capacity in solid media

A technique was developed for studying the biodegradative ability of white rot fungi in different solid media. This technique enables the gravimetric determination of fungal growth (increase of biomass) and the spectrometric measurement of fungal decolourization ability (both by the determination of the production of the extracellular enzyme manganese-dependent peroxidase (MnP) and by the rate of decolourization of dyes). Bjerkandera sp., strain BOS55, was grown in different solid media. Its growth rate, decolourization of solophenil blue 2BL (azoic dye), neutral red (eurhodin dye), methyl green and crystal violet (triphenylmethane dyes) and the production of MnP were determined. Application of this technique enabled a spectrometric quantification of enzymatic activity. Assays indicate that greater amounts of MnP were present in agar plate cultures of Bjerkandera sp. than in liquid cultures.     

Decolorization of Reactive Red 159 by a consortium of photosynthetic bacteria using an anaerobic sequencing batch reactor (AnSBR)

This experiment aimed to decolorize Reactive Red 159 using a high potential of a consortium of purple nonsulfur bacteria (PNSB) with an application of response surface methodology through a central composite design in open system. The three factors of hydraulic retention time (HRT), sludge retention time (SRT) and dye concentration were applied to the design. The decolorization was operated in an anaerobic sequencing batch reactor until the system reached to a pseudosteady state for 30?cycles in each experiment. The optimal condition was 6,500?mg/L of Reactive Red 159 concentration with 20 days of SRT and 8 days of HRT, achieving dye effluent of 142.62?±?5.35?mg/L, decolorization rate of 264.54?±?7.13?mg/L/h and decolorization efficiency of 97.68?±?0.74%. The results revealed that PNSB efficiently decolorized the high concentration of Reactive Red 159 and they were a high potential of microorganisms for dyes contaminated wastewater treatment.     

Decolorization of triphenylmethane, azo, and anthraquinone dyes by a newly isolated Aeromonas hydrophila strain

A broad-spectrum dye-decolorizing bacterium, strain DN322, was isolated from activated sludge of a textile printing wastewater treatment plant. The strain was characterized and identified as a member of Aeromonas hydrophila based on Gram staining, morphology characters, biochemical tests, and nearly complete sequence analysis of 16S rRNA gene and the gyrase subunit beta gene (gyrB). Strain DN322 decolorized a variety of synthetic dyes, including triphenylmethane, azo, and anthraquinone dyes. For color removal, the most suitable pH and temperature were pH 5.0–10.0 and 25–37°C, respectively. Triphenylmethane dye, e.g., Crystal Violet, Basic Fuchsin, Brilliant Green, and Malachite Green (50 mg l⁻¹) were decolorized more than 90% within 10 h under aerobic culture condition and Crystal Violet could be used as sole carbon source and energy source for cell growth. The color removal of triphenylmethane dyes was due to a soluble cytosolic enzyme, and the enzyme was an NADH/NADPH-dependent oxygenase; For azo and anthraquinone dyes, e.g., Acid Amaranth, Great Red GR, Reactive Red KE-3B, and Reactive Brilliant Blue K-GR (50 mg l⁻¹) could be decolorized more than 85% within 36 h under anoxic condition. This strain may be useful for bioremediation applications.     

A study on the utility of immobilized cells of indigenous bacteria for biodegradation of reactive azo dyes

Abstract

Azo dyes are recalcitrant compounds used as a colorant in various industries. The pollution caused by their extensive usage has adversely affected the environment for years. The existing physicochemical methods for dye pollution remediation are rather inefficient and hence there is a dearth of low-cost, potential systems capable of dye degradation. The current research studies the biodegradation potential of immobilized bacterial cells against azo dyes Reactive Orange 16 (RO-16) and Reactive Blue 250 (RB-250). Two indigenous dye degrading bacteria Bacillus sp. VITAKB20 and Lysinibacillus sp. KPB6 was isolated from textile sludge sample. Free cells of Bacillus. sp. VITAKB20 degraded 92.38% of RO-16 and that of Lysinibacillus sp. KPB6 degraded 95.36% of RB-250 within 72?h under static conditions. Upon immobilization with calcium alginate, dye degradation occurred rapidly. Bacillus. sp. VITAKB20 degraded 97.5% of RO-16 and Lysinibacillus sp. KPB6 degraded 98.2% of RB-250 within 48?h under shaking conditions. Further, the nature of dye decolorization was biodegradation as evident by high-performance liquid chromatography (HPLC), and Fourier-transform infrared spectroscopy (FTIR) results. Phytotoxicity and biotoxicity assays revealed that the degraded dye products were less toxic in nature than the pure dyes. Thus, immobilization proved to be a highly likely alternative treatment for dye removal.