Structure–activity Relationship Study on the Bioreduction of Azo Dyes by Clostridium Paraputrificum

Moir, D.C.; Masson, Sheila; Chu, Ih

doi:10.1897/1551-5028(2001)020<0479:sarsot>2.0.co;2

Cited by 7 publications

(4 citation statements)

References 13 publications

(19 reference statements)

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“…Azo dye reduction occurs preferentially under anoxic or oxygen-limited conditions (6,20,24,28,32,34,40,48). Under these circumstances, azo dyes act as terminal electron acceptors during microbial respiration.…”

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confidence: 99%

Characterization of Azo Reduction Activity in a Novel Ascomycete Yeast Strain

Ramalho

Cardoso²,

Cavaco‐Paulo³

et al. 2004

Appl Environ Microbiol

129

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Several model azo dyes are reductively cleaved by growing cultures of an ascomycete yeast species, Issatchenkia occidentalis. In liquid media containing 0.2 mM dye and 2% glucose in a mineral salts base, more than 80% of the dyes are removed in 15 h, essentially under microaerophilic conditions. Under anoxic conditions, decolorization does not occur, even in the presence of pregrown cells. Kinetic assays of azo reduction activities in quasi-resting cells demonstrated the following: (i) while the optimum pH depends on dye structure, the optimum pH range was observed in the acidic range; (ii) the maximum decolorizing activity occurs in the late exponential phase; and (iii) the temperature profile approaches the typical bell-shaped curve. These results indirectly suggest the involvement of an enzyme activity in azo dye reduction. The decolorizing activity of I. occidentalis is still observed, although at a lower level, when the cells switch to aerobic respiration at the expense of ethanol after glucose exhaustion in the culture medium. Decolorization ceased when all the ethanol was consumed; this observation, along with other lines of evidence, suggests that azo dye reduction depends on cell growth. Anthraquinone-2-sulfonate, a redox mediator, enhances the reduction rates of the N,N-dimethylaniline-based dyes and reduces those of the 2-naphthol-based dyes, an effect which seems to be compatible with a thermodynamic factor. The dye reduction products were tested as carbon and nitrogen sources. 1-Amino-2-naphthol was used as a carbon and nitrogen source, and N,N-dimethyl-p-phenylenediamine was used only as a nitrogen source. Sulfanilic and metanilic acids did not support growth either as a carbon or nitrogen source.Over the last two decades, considerable work has been done with the goal of using microorganisms as bioremediation agents in the treatment of wastewater containing textile dyes. These contaminants contribute a minor fraction to the usually high load of dissolved organic matter in textile effluents (35), but they are highly visible and must be removed in order to comply with the regulations concerning effluent discharge.Azo aromatic dyes are the major group of textile dyestuffs. These structures can be reductively cleaved into colorless amines by several bacterial species (for reviews, see references 2, 9, 41, and 43); nevertheless, azo dye reduction occurring in the presence of living matter can be an abiotic process. An example of this is the reduction of acid orange 7 (called dye IV in the present study) and reactive red 2 in anaerobic sludge, where sulfide, produced by sulfate-reducing microorganisms, can reduce azo bonds (45). In most of the reported processes of azo dye bioreduction, however, the participation of an enzymatic activity is assumed. Since the products of azo dye reduction, with few exceptions (4,11,26), cannot be used by bacteria as carbon and energy sources, the cleavage of azo bonds is a gratuitous process which can occur when the microorganisms use a reduced carbon compound as the gro...

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confidence: 99%

Characterization of Azo Reduction Activity in a Novel Ascomycete Yeast Strain

Ramalho

Cardoso²,

Cavaco‐Paulo³

et al. 2004

Appl Environ Microbiol

129

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“…Typically, this quicker transfer results in a higher rate of color removal [ 64 , 65 ]. The electron transfer phase can be accelerated with supplementation of small amount of redox mediator while lowering dye molecule steric hindrance [ 66 , 67 ].…”

Section: Resultsmentioning

confidence: 99%

Biodegradation of Azo Dye Methyl Red by Pseudomonas aeruginosa: Optimization of Process Conditions

Ikram

Naeem

Zahoor

et al. 2022

IJERPH

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Water pollution due to textile dyes is a serious threat to every life form. Bacteria can degrade and detoxify toxic dyes present in textile effluents and wastewater. The present study aimed to evaluate the degradation potential of eleven bacterial strains for azo dye methyl red. The optimum degradation efficiency was obtained using P. aeruginosa. It was found from initial screening results that P. aeruginosa is the most potent strain with 81.49% degradation activity and hence it was subsequently used in other degradation experiments. To optimize the degradation conditions, a number of experiments were conducted where only one variable was varied at a time and where maximum degradation was observed at 20 ppm dye concentration, 1666.67 mg/L glucose concentration, 666.66 mg/L sodium chloride concentration, pH 9, temperature 40 °C, 1000 mg/L urea concentration, 3 days incubation period, and 66.66 mg/L hydroquinone (redox mediator). The interactive effect of pH, incubation time, temperature, and dye concentration in a second-order quadratic optimization of process conditions was found to further enhance the biodegradation efficiency of P. aeruginosa by 88.37%. The metabolites of the aliquot mixture of the optimized conditions were analyzed using Fourier transform infrared (FTIR), GC-MS, proton, and carbon 13 Nuclear Magnetic Resonance (NMR) spectroscopic techniques. FTIR results confirmed the reduction of the azo bond of methyl red. The Gas Chromatography–Mass Spectrometry (GC-MS) results revealed that the degraded dye contains benzoic acid and o-xylene as the predominant constituents. Even benzoic acid was isolated from the silica gel column and identified by 1H and 13C NMR spectroscopy. These results indicated that P. aeruginosa can be utilized as an efficient strain for the detoxification and remediation of industrial wastewater containing methyl red and other azo dyes.

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“…For detailed information of cavitation training, the readers are requested to refer to previous references. The positive and negative pressures are exerted on a liquid, by the compression and expansion of ultrasonic wave cycles, respectively [93][94][95][96][97][98][99][100]. When the negative pressure applied on the liquid is sufficiently high, the average distance between the molecules would exceed the critical molecular distance necessary to maintain the intact liquid and the liquid will break down to form cavities in vapor and gas-filled micro bubbles.…”

Section: Sonolysis Processmentioning

confidence: 99%

Industrial Wastewater Treatment: A Challenging Task in the Industrial Waste Management

Mp¹

2017

Adv Recycling Waste Manag

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Structure–activity Relationship Study on the Bioreduction of Azo Dyes by Clostridium Paraputrificum

Cited by 7 publications

References 13 publications

Characterization of Azo Reduction Activity in a Novel Ascomycete Yeast Strain

Characterization of Azo Reduction Activity in a Novel Ascomycete Yeast Strain

Biodegradation of Azo Dye Methyl Red by Pseudomonas aeruginosa: Optimization of Process Conditions

Industrial Wastewater Treatment: A Challenging Task in the Industrial Waste Management

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