Soybean peroxidase-catalysed removal of benzidines from                water

Altahir, Bahaa Malik; FengWei,; Hassan, JasimHadi; E, TaylorKeith; BiswasNiharendu,; BewtraJatinder, K; JassimSabah, A A

doi:10.1680/jenes.15.00018

Cited by 9 publications

(6 citation statements)

References 34 publications

(50 reference statements)

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“…Also, it is noted that benzidine conversion would not be the ''limiting factor'' (because it requires much less enzyme concentration than aniline). This lower requirement for benzidine as SBP substrate was reported by Malik Altahir et al (2015) where 0.10 mM benzidine required 0.43 mU/mL SBP.…”

Section: Resultsmentioning

confidence: 48%

“…It can be observed that the optimum pH was 5.0 for total amines as well as aniline and benzidine. For authentic aniline and benzidine optimum pHs with SBP have also been reported as pH 5.0 (Malik Altahir et al, 2015;Mazloum et al, 2016); thus, further experiments in this research (enzyme and H 2 O 2 optimization) were done at this pH. Also, it is noted that benzidine conversion would not be the ''limiting factor'' (because it requires much less enzyme concentration than aniline).…”

Section: Resultsmentioning

confidence: 88%

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Soybean Peroxidase‐Catalyzed Treatment of Azo Dyes with or without Fe° Pretreatment

Villegas

Mazloum

Taylor

et al. 2018

Water Environment Research

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Representative azo dyes (Acid Blue 113 [AB113] and Direct Black 38 [DB38]) were treated in a single step with soybean peroxidase (SBP) and hydrogen peroxide (H2O2), or in two steps, zero-valent iron (Fe°) pretreatment followed SBP/H2O2. The purpose of this research was to compare both treatment processes and to determine which one was the optimal for degradation of each azo dye. For AB113, the preferred process was the single-step process, 1.0 mM AB113 required 2.5 mM H2O2, 1.5 U/mL SBP at pH 4.0 for ≥ 95% color and dye removal and 30% total organic carbon (TOC) removal. For DB38, due to the products formed after Fe° reduction, which are enzyme substrates (aniline and benzidine; two of four products) a two-step process was preferred, which allowed reduction in the required SBP and H2O2 concentrations by 5- and 2-fold, respectively, compared to a single-step treatment for ≥ 95% color, dye, and aniline/benzidine removal and 88% TOC removal.

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Section: Resultsmentioning

confidence: 48%

Section: Resultsmentioning

confidence: 88%

Soybean Peroxidase‐Catalyzed Treatment of Azo Dyes with or without Fe° Pretreatment

Villegas

Mazloum

Taylor

et al. 2018

Water Environment Research

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“…Mukherjee et al . found pH 4.6 to be optimal for removal of p ‐cresidine (pK a 4.7) using SBP 22 and pH 5.0 optimal for removal of benzidine using SBP 23 . Thus, the optimal pH for enzymatic treatment is close to the pK a of anilino compounds.…”

Section: Resultsmentioning

confidence: 98%

Soybean peroxidase‐catalyzed degradation of a sulfonated dye and its azo‐cleavage product

Kaur

Taylor

Biswas

2020

J of Chemical Tech & Biotech

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BACKGROUNDThe presence of azo dyes in wastewater from the textile industry is a major environmental concern. The dyes not only make water aesthetically unacceptable, but also have severe toxicological concerns. Research into treatment processes for removal of dyes has focused primarily on decolourization and little attention has been focused on analysis of the degradation products, that could plausibly be more toxic than the parent compound. This study focusses on soybean peroxidase (SBP)‐catalyzed treatment of two azo dyes, Methyl Orange (MO) and CI Direct Yellow 12 (DY12) in water, chosen because they lack phenolic and primary anilino functional groups, which are usually expected to form free radicals under peroxidase catalysis.RESULTSDY12 was found not to be a substrate of SBP, but optimized reaction conditions for 0.50 mmol L–1 MO and 1.0 mmol L–1 p‐anisidine (structurally analogous to 4‐ethoxyaniline, a possible azo‐cleavage product of DY12) achieved ≥95% conversion at exceptionally low minimum effective SBP activities (0.0070 and 0.0018 U mL–1) at pH optima of 4.0 and 5.5 and [hydrogen peroxide]/[substrate] of 2 and 1, respectively.CONCLUSIONSMass spectrometric (MS) analysis for the substrates revealed formation of dimers and trimers for p‐anisidine. For MO, high‐performance liquid chromatography, UV‐visible spectrophotometry and MS provided evidence of azo‐bond cleavage, hetero‐coupling of the dye with the cleavage product and also self‐coupling of the dye through tertiary amine activation. © 2020 Society of Chemical Industry (SCI)

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“…The sample dilution was adjusted according to the expected enzyme activity (to have approximately 0.2 absorbance change in 30 seconds). 35 One unit of SBP activity is defined as the amount catalyzing 1 μmol of hydrogen peroxide conversion per minute under the assay conditions. 29…”

Section: Soybean Peroxidase Activity Assaymentioning

confidence: 99%

“…Aliquots (5 mL) were withdrawn by micropipette at various time intervals, quenched with 0.25 mL catalase solution and then centrifuged, micro-filtered and analyzed by a spectrophotometer. Centrifugation was used for quick sample preparation in order to get a clear liquid sample 35.…”

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confidence: 99%

Soybean Peroxidase Catalyzed Decoloration of Acid Azo Dyes

Altahir

Al-robaiey

Abbaas

et al. 2020

Journal of Health and Pollution

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Background. Some industrial manufacturing processes generate and release dyes as water pollutants, many of which are toxic and hazardous materials. There is a need for milder, greener methods for dye treatment. Objectives. The objective of the present study was to investigate and optimize azo dye decoloration by a crude soybean peroxidase (SBP), based on two dyes that have widespread industrial use, but that differ greatly in structural complexity, Acid Black 2 and Acid Orange 7, and to investigate the effects of specific parameters on the removal process. Methods. Batch reactors were used to remove 95% of the dyes' color and to produce substantial precipitates. Results. The optimum pH for enzymatic decoloration of Acid Black 2 was in the acidic region, pH 4.4, and that of Acid Orange 7 occurred under neutral conditions, pH 6.9. The minimum enzyme activity needed for sufficient removal was 1.2 U/mL for both dyes at 0.5 mM. The minimum molar hydrogen peroxide/substrate ratio was 3 for Acid Orange 7 and 2.5 for Acid Black 2 to achieve approximately 95% removal. First-order fitting of progress curve data collected under the respective optimum conditions gave half-lives of 23.9 and 28.9 minutes for Acid Orange 7 and Acid Black 2, respectively. Conclusions. The feasibility of SBP-catalyzed treatment of industrial dyes Acid Black 2 and/or Acid Orange 7, or dyes that resemble them, as they might occur in industrial effluents, was successfully demonstrated. Competing Interests.The authors declare no competing financial interests

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Soybean peroxidase-catalysed removal of benzidines from water

Cited by 9 publications

References 34 publications

Soybean Peroxidase‐Catalyzed Treatment of Azo Dyes with or without Fe° Pretreatment

Soybean Peroxidase‐Catalyzed Treatment of Azo Dyes with or without Fe° Pretreatment

Soybean peroxidase‐catalyzed degradation of a sulfonated dye and its azo‐cleavage product

Soybean Peroxidase Catalyzed Decoloration of Acid Azo Dyes

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