Biodegradation and detoxification of textile azo dyes by bacterial consortium under sequential microaerophilic/aerobic processes

Lade, Harshad; Kadam, Avinash A.; Paul, Diby; Govindwar, Sanjay P.

doi:10.17179/excli2014-642

Cited by 48 publications

(22 citation statements)

References 54 publications

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“…Toxicity changes after LAC_2.9 decolorization must still be evaluated. Nevertheless, recent decolorization studies involving bacterial laccases proved their ability to detoxify several azo dyes (Blánquez et al 2019;Lade et al 2015;Molina-Guijarro et al 2009;Pereira et al 2009;Xia et al 2019).…”

Section: Fungalmentioning

confidence: 99%

Fast decolorization of azo dyes in alkaline solutions by a thermostable metal-tolerant bacterial laccase and proposed degradation pathways

et al. 2020

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Biocatalytic decolorization of azo dyes is hampered by their recalcitrance and the characteristics of textile effluents. Alkaline pH and heavy metals present in colored wastewaters generally limit the activity of enzymes such as laccases of fungal origin; this has led to an increasing interest in bacterial laccases. In this work, the dye decolorization ability of LAC_2.9, a laccase from the thermophilic bacterial strain Thermus sp. 2.9, was investigated. Its resistance towards different pHs and toxic heavy metals frequently present in wastewaters was also characterized. LAC_2.9 was active and highly stable in the pH range of 5.0 to 9.0. Even at 100 mM Cd +2 , As +5 and Ni +2 LAC_2.9 retained 99%, 86% and 75% of its activity, respectively. LAC_2.9 was capable of decolorizing 98% of Xylidine, 54% of RBBR, 40% of Gentian Violet, and 33% of Methyl Orange after 24 h incubation at pH 9, at 60 °C, without the addition of redox mediators. At acidic pH, the presence of the mediator 1-hydroxybenzotriazole generally increased the catalytic effectiveness. We analyzed the degradation products of laccasetreated Xylidine and Methyl Orange by capillary electrophoresis and mass spectrometry, and propose a degradation pathway for these dyes. For its ability to decolorize recalcitrant dyes, at pH 9, and its stability under the tested conditions, LAC_2.9 could be effectively used to decolorize azo dyes in alkaline and heavy metal containing effluents.

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Section: Fungalmentioning

confidence: 99%

Fast decolorization of azo dyes in alkaline solutions by a thermostable metal-tolerant bacterial laccase and proposed degradation pathways

et al. 2020

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“…However, they are categorized into azo, indigo, anthraquinone, phthalocyanine, nitroso and nitro, etc., according to their chemical nature [ 3 , 5 ]. As reported by [ 6 , 7 ], azo dyes account for more than 70% of commercially used organic dyes by the dint of their ease in synthesis, higher water solubility and higher stability under different conditions such as temperature, light, detergent and microbial deterioration. Their chemical structure could be described as an aromatic system conjugated to one or more of chromophore azo (–N=N–) groups and an auxochrome sulfonic (SO −3 ) groups associated with hydroxyl, methyl, chloro, triazine amine and nitro [ 1 , 3 ].…”

Section: Introductionmentioning

confidence: 99%

“…The inefficient dyeing process, in particular the fixation step, causes 10–70% of the amount used being discharged into the aquatic ecosystem as effluents [ 6 – 8 , 13 ]. In fact, the concentration of unfixed dyes in textile effluents is estimated to be 10–200 mg/L [ 7 , 14 ]. However, their presence in negligible concentrations in the range of 10–50 mg/L is considered a major environmental and public health concern [ 7 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

“…In fact, the concentration of unfixed dyes in textile effluents is estimated to be 10–200 mg/L [ 7 , 14 ]. However, their presence in negligible concentrations in the range of 10–50 mg/L is considered a major environmental and public health concern [ 7 , 15 ]. At such concentrations, the water transparency is adversely influenced by clearly visible dye, which certainly exerts several impacts such as diminishing light penetration, blocking photosynthesis of phytoplankton and algae, altering pH, reducing dissolved oxygen (DO), elevating the biological oxygen demand (BOD) and chemical oxygen demand (COD), which ultimately disrupt the quality of aquatic ecosystem.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the presence of azo dyes or their aromatic by-products in water causes shortness of breath, vomiting, diarrhea, sweating, allergy and hypopigmentation. Notably, some carcinogenic, mutagenic and neurotoxic effects of them have also been reported [ 7 , 15 , 16 ]. Therefore, to reduce these environmental pollution and human health risks, the environmental legislation has enforced dyestuff manufacturers to treat effluents contaminated with dyes prior to their discharge into open streams [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

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Statistical modeling of methylene blue degradation by yeast-bacteria consortium; optimization via agro-industrial waste, immobilization and application in real effluents

et al. 2021

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The progress in industrialization everyday life has led to the continuous entry of several anthropogenic compounds, including dyes, into surrounding ecosystem causing arduous concerns for human health and biosphere. Therefore, microbial degradation of dyes is considered an eco-efficient and cost-competitive alternative to physicochemical approaches. These degradative biosystems mainly depend on the utilization of nutritive co-substrates such as yeast extract peptone in conjunction with glucose. Herein, a synergestic interaction between strains of mixed-culture consortium consisting of Rhodotorula sp., Raoultella planticola; and Staphylococcus xylosus was recruited in methylene blue (MB) degradation using agro-industrial waste as an economic and nutritive co-substrate. Via statistical means such as Plackett–Burman design and central composite design, the impact of significant nutritional parameters on MB degradation was screened and optimized. Predictive modeling denoted that complete degradation of MB was achieved within 72 h at MB (200 mg/L), NaNO3 (0.525 gm/L), molasses (385 μL/L), pH (7.5) and inoculum size (18%). Assessment of degradative enzymes revealed that intracellular NADH-reductase and DCIP-reductase were key enzymes controlling degradation process by 104.52 ± 1.75 and 274.04 ± 3.37 IU/min/mg protein after 72 h of incubation. In addition, azoreductase, tyrosinase, laccase, nitrate reductase, MnP and LiP also contributed significantly to MB degradation process. Physicochemical monitoring analysis, namely UV−Visible spectrophotometry and FTIR of MB before treatment and degradation byproducts indicated deterioration of azo bond and demethylation. Moreover, the non-toxic nature of degradation byproducts was confirmed by phytotoxicity and cytotoxicity assays. Chlorella vulgaris retained its photosynthetic capability (˃ 85%) as estimated from Chlorophyll-a/b contents compared to ˃ 30% of MB-solution. However, the viability of Wi-38 and Vero cells was estimated to be 90.67% and 99.67%, respectively, upon exposure to MB-metabolites. Furthermore, an eminent employment of consortium either freely-suspended or immobilized in plain distilled water and optimized slurry in a bioaugmentation process was implemented to treat MB in artificially-contaminated municipal wastewater and industrial effluent. The results showed a corporative interaction between the consortium examined and co-existing microbiota; reflecting its compatibility and adaptability with different microbial niches in different effluents with various physicochemical contents.

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Environmental Effects and Microbial Detoxification of Textile Dyes

Maqbool¹,

Nadeem²,

Mahmood³

et al. 2020

Methods for Bioremediation of Water and Wastewater Pollution

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Biodegradation and detoxification of textile azo dyes by bacterial consortium under sequential microaerophilic/aerobic processes

Cited by 48 publications

References 54 publications

Fast decolorization of azo dyes in alkaline solutions by a thermostable metal-tolerant bacterial laccase and proposed degradation pathways

Fast decolorization of azo dyes in alkaline solutions by a thermostable metal-tolerant bacterial laccase and proposed degradation pathways

Statistical modeling of methylene blue degradation by yeast-bacteria consortium; optimization via agro-industrial waste, immobilization and application in real effluents

Environmental Effects and Microbial Detoxification of Textile Dyes

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