ArticlePDF Available

Mycoremediation of azo dyes using Cyberlindnera fabianii yeast strain: Application of designs of experiments for decolorization optimization

Authors:
Mohammed Danouche at Mohammed VI Polytechnic University
Mohammed Danouche
Mohamed Ferioun at Sidi Mohamed Ben Abdellah University
Mohamed Ferioun
Wifak Bahafid at Sidi Mohamed Ben Abdellah University
Wifak Bahafid
Naima el ghachtouli at Sidi Mohamed Ben Abdellah University
Naima el ghachtouli
Download full-text PDF
Read full-text
Download citation

Abstract

This study investigated the dye decolorization capacity of three yeast strains. Cyberlindnera fabianii was shortlisted for its high decolorization capacity and was further tested on various azo dyes. Based on the color of the biomass, and the UV–Vis analysis, Acid Red 14 was selected as a model dye, to examine the enzymatic biodegradation. The results showed significant increase in the intracellular and extracellular activities of laccase, tyrosinase, manganese peroxidase, and azoreductase. Phytotoxicity assessment indicated that the AR14 biodegradation by‐products were not phytotoxic compared to the original dye molecules. Regarding the decolorization optimization, the screening of factors using the Plackett–Burman design showed that pH, dye concentration, and shaking speed had significant effects. These factors and their combined effect were evaluated using response surface methodology with the Box–Behnken model. The pH was the most significant factor, followed by dye concentration. The analysis of the contour plot and the 3D response surface diagram showed that the decolorization was inversely proportional to the increase in the initial dye concentration, but proportional to the initial pH and shaking speed. At optimal conditions (pH = 5.154, AR14 = 50 mg/L), C. fabianii could decolorize more than 97% of AR14 within 12 hr. Practitioner points Cyberlindnera fabianii is a successful candidate for dye mycoremediation. Oxidase and reductase are the key enzymes involved in the biodegradation of azo dyes. By‐products of Acid red 14 biodegradation are not phytoxic compared to the original dye. Design of experience tools enables to determine optimum conditions for efficient decolorization.
Content uploaded by Mohammed Danouche
Author content
All content in this area was uploaded by Mohammed Danouche on Dec 18, 2020
Content may be subject to copyright.
18/12/2020
Mycoremediation of azo dyes using Cyberlindnera fabianii yeast strain: Application of designs of experiments for decolorization optimiza…
https://onlinelibrary.wiley.com/doi/epdf/10.1002/wer.1499 1/3
RESEARCH ARTICLE
Mycoremediation of azo dyes using Cyberlindnera fabianii yeast strain: Application of
designs of experiments for decolorization optimization
M. Danouche , M. Ferioun , W. Bahad , N. El Ghachtouli
First published: 17 December 2020
https://doi.org/10.1002/wer.1499
This article has been accepted for publication and undergone full peer review but has not been through the copyediting,
typesetting, pagination and proofreading process, which may lead to dierences between this version and the Version of
Record. Please cite this article as doi:10.1002/wer.1499
Get access to the full version of this article. View access options below.
Log in
Institutional Login
Access through your institution
Log in to Wiley Online Library
If you have previously obtained access with your personal account, please log in.
Purchase Instant Access
Details
Details
Details
48-Hour online access $7.00
Online-only access $16.00
PDF download and online access $42.00
18/12/2020
Mycoremediation of azo dyes using Cyberlindnera fabianii yeast strain: Application of designs of experiments for decolorization optimiza…
https://onlinelibrary.wiley.com/doi/epdf/10.1002/wer.1499 2/3
Download PDF
About Wiley Online Library
Privacy Policy
Terms of Use
Cookies
Accessibility
Help & Support
Contact Us
Opportunities
Subscription Agents
Advertisers & Corporate Partners
Connect with Wiley
The Wiley Network
Wiley Press Room
Abstract
Check out
This study investigated the dye decolorization capacity of three yeast strains. Cyberlindnera fabianii was
shortlisted for its high decolorization capacity and was further tested on various azo dyes. Based on the
color of the biomass, and the UV‐Vis analysis, Acid red 14 was selected as a model dye, in order to
examine the enzymatic biodegradation. The results showed signicant increase in the intracellular and
extracellular activities of laccase, tyrosinase, manganese peroxidase, and azoreductase. Phytotoxicity
assessment indicated that the AR14 biodegradation by‐products were not phytotoxic compared to the
original dye molecules. Regarding the decolorization optimization, the screening of factors using the
Plackett–Burman design showed that pH, dye concentration, and shaking speed had signicant eects.
These factors and their combined eect were evaluated using response surface methodology with the
Box‐Behnken model. The pH was the most signicant factor, followed by dye concentration. The
analysis of the contour plot and the 3D‐response surface diagram showed that the decolorization was
inversely proportional to the increase in the initial dye concentration, but proportional to the initial pH
and shaking speed. At optimal conditions (pH=5.154, AR14=50 mg.L ), C. fabianii could decolorize more
than 97% of AR14 within 12 h.
‐1
18/12/2020
Mycoremediation of azo dyes using Cyberlindnera fabianii yeast strain: Application of designs of experiments for decolorization optimiza…
https://onlinelibrary.wiley.com/doi/epdf/10.1002/wer.1499 3/3
Copyright © 1999-2020 John Wiley & Sons, Inc. All rights reserved
... The assessment of phytotoxicity was conducted to evaluate the ecotoxicological effectiveness of the ultrasonic photo-Fenton treatment process. This study employed Medicago sativa (alfalfa) seeds as a representative plant model [28]. To ensure a sterile environment, the seeds underwent sequential immersions: first in a 95 % ethanol solution for 5 Table 3 The experimental matrix and the respective responses values of COD, UV 254 , and color removal in sono-photo-Fenton system. ...
Remediation of the landfill leachate of Fez city (Morocco) by sono-photo-Fenton process: Cost and phytotoxicity assessment
Article
  • Dec 2023
A new Advanced Oxidation process (AOP) using the ultrasound-photo-Fenton process (US-P-FP) was used to treat stabilized landfill leachate from Fez City (Morocco). The effectiveness of the US-P-FP for landfill leachate treatment was investigated in terms of COD, UV254, and color removal. The operating factors (Fe2+ dosage, pH, H2O2 dosage, ultrasonic (US), UV-A) were optimized by the two-level factorial design. The findings reveal that the highest removal of COD, UV254, and color from the landfill leachate was 93 %, 77 %, and 98 %, respectively, at the optimum operation conditions [Fe2+] = 446 mg/L, [H2O2] = 250 mg/L and a pH = 3 in the presence of both US and UV-A irradiations. The phytotoxicity assessment of untreated and sono-photo-Fenton treated leachate samples was conducted through seed germination and root elongation tests using Medicago sativa seeds as bioindicators. The experimental results showed that the ultrasound-photo-Fenton process allowed a significant phytotoxicity reduction. Overall, the sono-photo-Fenton process proves to be a viable and efficient method for landfill leachate treatment.
View
... The assessment of phytotoxicity was conducted to evaluate the ecotoxicological effectiveness of the ultrasonic photo-Fenton treatment process. This study employed Medicago sativa (alfalfa) seeds as a representative plant model [28]. To ensure a sterile environment, the seeds underwent sequential immersions: first in a 95 % ethanol solution for 5 Table 3 The experimental matrix and the respective responses values of COD, UV 254 , and color removal in sono-photo-Fenton system. ...
View
... This approach efficiently selects factors and determines their optimum levels, resulting in a reduced number of experimental trials needed to evaluate multiple parameters and their interactions [24]. In this study, the Plackett-Burman design (PBD) was employed for the selection of main factors influencing SO 4 2− leaching from PG. Subsequently, the Box-Behnken design (BBD) was used to optimize interactions among the three main PBD-based selection factors and predict optimal conditions for high SO 4 2− leaching from PG by using the BBD [25]. ...
Optimization of sulfate leaching from Phosphogypsum for efficient bioreduction in a batch bioreactor using a sulfate-reducing microbial consortium
Article
  • Sep 2023
  • CHEM ENG J
Phosphogypsum (PG) is generated annually from phosphoric acid production. This by-product contains 50% of sulfate (SO42−), which can be recycled biologically. Biorecovery of elemental sulfur (S0) involves firstly converting SO42− into biogenic sulfide using sulfate-reducing bacteria under anaerobic conditions, then oxidizing the sulfide produced into S0 using sulfur-oxidizing bacteria. This study focused on selecting and evaluating natural microbial consortia from SO42− rich biotopes for their application in the initial first step of S0 biorecovery. The PG sample was first comprehensively characterized using ICP-MS/OES, XRD, FTIR, and TGA analyses. Subsequently, SO42− leaching optimization was performed through a design of experiments approach. The analysis revealed that CaSO4 was the major component of the PG (78%), and the optimal parameters for leaching of SO42− from PG were at a NaOH concentration of 7.4% and PG concentration of 158 g.L−1. Furthermore, the MYC-consortium isolated from a hydrothermal niche demonstrated the highest reduction capacity among the studied consortia. It also exhibited the highest performance under SO42− concentrations up to 3.5 g.L−1, salinity levels up to 30 g.L−1, and in the presence of 60 ppm of Zn(II), 3 ppm of Cd(II), and 6 ppm of Pb(II). Moreover, this consortium showed a high capacity for reducing SO42− in the bioreactor (90% after 6 weeks) when utilizing SO42− from the PG-leached solution, as attested by the chemical analyses of the precipitate formed in the bioreactor. This research offers a comprehensive insight into the potential of MYC-consortium to convert leached SO42− from PG into sulfide, which is the most critical step in the S0-biorecovery.
View
... Biodegradation is a process that is impacted by a variety of factors. By controlling these factors, the biodegradation process will be more rapid and much more effective, decreasing the cost and reducing the time of remediation procedures [44]. ...
Role of Microorganisms in Biodegradation of Pollutants
Chapter
Full-text available
  • Feb 2023
Environmental pollution through industrial development has led to the generation of a variety of lethal materials, especially recalcitrant classes such as polycyclic aromatic hydrocarbons, toxic dyes, pesticides, and heavy metals, which are now of critical environmental importance due to their harmful and mutagenic effects on humans, plants, and aquatic organisms. Biodegradation is naturally performed by microorganisms, implying the decomposition of complex organic compounds into a more straightforward inorganic form. These organisms will harness these organisms as a source of energy, while bioremediation is a human engineering technology that reduces pollutants using microorganisms through techniques of natural attenuation, biostimulation, or bioaugmentation to strengthen the ability of microorganisms. Various microorganisms can degrade environmental pollutants with promising skills like bacteria, fungi, algae, and protozoa. Certain parameters must be established to provide the highest biodegradation rate of degradable microorganisms under the optimum conditions. These factors are biological factors such as bioavailability, nutrient availability, culture type and type of microorganism, and environmental factors such as pH, temperature, oxygen availability, and pollutant concentration. Biodegradation mechanisms depend mainly on microbial enzymes such as oxidoreductases, hydrolases, peroxidase, oxygenase, proteases, lipases, and lacquers. Genetically modified microorganisms have been applied to further improve the remediation of pollutants and ensure safe biodegradation using symbiotic microorganisms.
View
... The multisequence phylogenetic analysis confirmed the taxonomic affiliation of the RODW isolates with the Cyberlindnera genus and their closer affiliation with the Cyberlindnera rhodanensis species. The genus Cyberlindnera was introduced as a replacement name for the genus Lindnera and currently accommodates over thirty species, some of which are associated with the fermentation of plant biomass and wastes, as well as phenolic-rich beverages and food products [26][27][28][29][30][31][32][33][34]. In the present study, the fermentation of RODW by the tested indigenous yeast isolates resulted in the fermentation of around 80% of the reducing sugars present in the RODW and a decrease in the phenolic content to around 60% of the initial concentration in the RODW. ...
Indigenous Yeasts from Rose Oil Distillation Wastewater and Their Capacity for Biotransformation of Phenolics
Article
Full-text available
  • Jan 2023
The indigenous yeasts associated with the spontaneous fermentation of phenolic-rich rose oil distillation wastewater (RODW) generated after the industrial distillation of rose oil were studied. The ITS-rDNA sequence analysis of the samples collected from RODW fermented at semi-sterile conditions, a waste deposition lagoon and endophytic yeasts isolated from industrially cultivated Rosa damascena suggests that the spontaneous RODW fermentation is caused by yeasts from the genus Cyberlindnera found also as endophytes in the rose flowers. Phylogenetic analysis based on the nucleotide sequences of the translation elongation factor (TEF1α) and 18S- and 26S- rRNA genes further confirmed the taxonomic affiliation of the RODW yeast isolates with the genus Cyberlindnera. The RODW fermentation capacity of a selected set of indigenous yeast isolates was studied and compared with those of common yeast strains. The indigenous yeast isolates demonstrated a superior growth rate, resulting in a nearly double reduction in the phenolic content in the fermented RODW. The indigenous yeasts’ fermentation changed the RODW phenolics’ composition. The levels of some particular phenolic glycosides decreased through the depletion and fermentation of their sugar moiety. Hence, the relative abundance of the corresponding aglycons and other phenolic compounds increased. The capacity for the biotransformation of RODW phenolics by indigenous yeasts is discussed.
View
... For example, the use of surfactin in charcoal flotation was reported to be effective through enhancing the hydrophobicity of the coal surface at several pH value, namely 3, 6 and 10 (Augustyn et al. 2021). In the interest of researching new sources of reagents used in ore processing, commercial baker's yeast cells Saccharomyces cerevisiaea were applied thanks to their simple industrial cultivation (Danouche et al. 2021b(Danouche et al. , 2022. Microflotation tests were performed to evaluate the effect of pH on apatite recovery. ...
A critical review on natural surfactants and their potential for sustainable mineral flotation
Article
Full-text available
  • Nov 2022
  • Rev Environ Sci Biotechnol
The transition of the mineral processing sectors, which depend mainly on various petroleum-origin chemicals, to the green industry based on the production of greener materials and the reduction of carbon footprints, is mandatory due to the growing concerns regarding the extensive environmental impact of the mining industry. In this context, biological ore beneficiation is spurring increasing interest from scientists and industrials. The latest scientific developments in bio-metallurgy have allowed it to exploit biotechnologies in the flotation process as a novel/cleaner approach for separating gangue materials from valuables minerals. Current fundamental research projects have focused on the progress of biotechnology and the employment of biopolymers, microorganisms, and their metabolites, as well as plant-derived biosurfactants in the emerging field of bioprocessing, particularly bioflotation. Almost all studies on flotation have focused on chemical and physical parameters, and the role of natural biosurfactants remains little explored. This review presents a thorough understanding of the bioflotation concept by assessing previous research on several elements of bioflotation, including the impacts of biotechnology and operating factors (pH, biomass, and biosurfactants concentration), probable mechanisms, and unexplored areas, but from various pragmatic viewpoints. Recent studies are summarized by categorizing microorganisms, plants, and biopolymers based on their bioflotation performances. Furthermore, the most recent research investigations on biological flotation of specific minerals (salt-type sulphide and oxide) are reviewed. Finally, critical challenges of bioflotation are discussed, and novel perspectives are provided to contribute to solving the difficulties faced in its implementation. Graphical abstract
View
View
Fungal bioremediation approaches for the removal of toxic pollutants: Mechanistic understanding for biorefinery applications
Article
  • Jan 2024
  • CHEMOSPHERE
Pollution is a global menace that poses harmful effects on all the living ecosystems and to the Earth. As years pass by, the available and the looming rate of pollutants increases at a faster rate. Although many treatments and processing strategies are waged for treating such pollutants, the by-products and the wastes or drain off generated by these treatments further engages in the emission of hazardous waste. Innovative and long-lasting solutions are required to address the urgent global issue of hazardous pollutant remediation from contaminated environments. Myco-remediation is a top-down green and eco-friendly tool for pollution management. It is a cost-effective and safer practice of converting pernicious substances into non-toxic forms by the use of fungi. But these pollutants can be transformed into useable products along with multiple benefits for the environment such as sequestration of carbon emissions and also to generate high valuable bioactive materials that fits as a sustainable economic model. The current study has examined the possible applications of fungi in biorefineries and their critical role in the transformation and detoxification of pollutants. The paper offers important insights into using fungal bioremediation for both economically and environmentally sound solutions in the domain of biorefinery applications by combining recent research findings.
View
View
Biodegradation of Environmental Pollutants by Marine Yeasts
Chapter
Full-text available
  • Jan 2023
Organic contaminants are among the main pollutants of ecosystems because of their presence in domestic, agricultural, or industrial effluents. Indeed, many organic xenobiotics such as aromatic hydrocarbons, pesticides, synthetic dyes, etc., are not easily biodegradable in the environment and can therefore accumulate in ecosystems causing various toxic symptoms in exposed organisms, including humans. Yeast-assisted biological treatment has emerged as a promising new strategy for the biodegradation of such hazardous contaminants. Firstly, this chapter provides an overview of the applications of yeast in the biodegradation of organic contaminants. Subsequently, synthetic dyes were chosen as a model of organic pollutants to highlight the enzymes involved in their biodegradation process using various yeast strains. Indeed, the main oxidases involved are laccase, tyrosinase, lignin peroxidase, and manganese peroxidase. While the main reductases are Azoreductase, NADH-DCIP reductase, and malachite green reductase. The last section highlights the effects of physicochemical conditions on the effectiveness of mycoremediation.
View
Performance of a Newly Isolated Salt-Tolerant Yeast Strain Sterigmatomyces halophilus SSA-1575 for Azo Dye Decolorization and Detoxification
Article
Full-text available
  • Jun 2020
The effective degradation of hazardous contaminants remains an intractable challenge in wastewater processing, especially for the high concentration of salty azo dye wastewater. However, some unique yeast symbionts identified from the termite gut system present an impressive function to deconstruct some aromatic compounds, which imply that they may be valued to work on the dye degradation for various textile effluents. In this investigation, a newly isolated and unique yeast strain, Sterigmatomyces halophilus SSA-1575, was identified from the gut system of a wood-feeding termite (WFT), Reticulitermes chinensis. Under the optimized ambient conditions, the yeast strain SSA-1575 showed a complete decolorization efficiency on Reactive Black 5 (RB5) within 24 h, where this azo dye solution had a concentration of a 50 mg/L RB5. NADH-dichlorophenol indophenol (NADH-DCIP) reductase and lignin peroxidase (LiP) were determined as the key reductase and oxidase of S. halophilus SSA-1575. Enhanced decolorization was recorded when the medium was supplemented with carbon and energy sources, including glucose, ammonium sulfate, and yeast extract. To understand a possible degradation pathway well, UV-Vis spectroscopy, FTIR and Mass Spectrometry analyses were employed to analyze the possible decolorization pathway by SSA-1575. Determination of relatively high NADH-DCIP reductase suggested that the asymmetric cleavage of RB5 azo bond was mainly catalyzed by NADH-DCIP reductase, and finally resulting in the formation of colorless aromatic amines devoid of any chromophores. The ecotoxicology assessment of RB5 after a decolorization processing by SSA-1575, was finally conducted to evaluate the safety of its metabolic intermediates from RB5. The results of Microtox assay indicate a capability of S. halophilus SSA-1575, in the detoxification of the toxic RB5 pollutant. This study revealed the effectiveness of halotolerant yeasts in the eco-friendly remediation of hazardous pollutants and dye wastewater processing for the textile industry.
View
Ligninolytic enzymes and its mechanisms for degradation of lignocellulosic waste in environment
Article
Full-text available
  • Feb 2020
Ligninolytic enzymes play a key role in degradation and detoxification of lignocellulosic waste in environment. The major ligninolytic enzymes are laccase, lignin peroxidase, manganese peroxidase, and versatile peroxidase. The activities of these enzymes are enhanced by various mediators as well as some other enzymes (feruloyl esterase, aryl-alcohol oxidase, quinone reductases, lipases, catechol 2, 3-dioxygenase) to facilitate the process for degradation and detoxification of lignocellulosic waste in environment. The structurally laccase is isoenzymes with monomeric or dimeric and glycosylation levels (10-45%). This contains four copper ions of three different types. The enzyme catalyzes the overall reaction: 4 benzenediol + O2 to 4 benzosemiquinone + 2H2O. While, lignin peroxidase is a glycoprotein molecular mass of 38-46 kDa containing one mole of iron protoporphyrin IX per one mol of protein, catalyzes the H2O2 dependent oxidative depolymerization of lignin. The manganese peroxidase is a glycosylated heme protein with molecular mass of 40-50kDa. It depolymerizes the lignin molecule in the presence of manganese ion. The versatile peroxidase has broad range substrate sharing typical features of the manganese and lignin peroxidase families. Although ligninolytic enzymes have broad range of industrial application specially the degradation and detoxification of lignocellulosic waste discharged from various industrial activities, its large scale application is still limited due to lack of limited production. Further, the extremophilic properties of ligninolytic enzymes indicated their broad prospects in varied environmental conditions. Therefore it needs more extensive research for understanding its structure and mechanisms for broad range commercial applications.
View
Performances of Pichia kudriavzevii in decolorization, biodegradation, and detoxification of C.I. Basic Blue 41 under optimized cultural conditions
Article
Full-text available
  • Jan 2019
  • ENVIRON SCI POLLUT R
The aim of this study was to evaluate the performances of Pichia kudriavzevii CR-Y103 yeast strain for the decolorization, biodegradation, and detoxification of cationic dye C.I. Basic Blue 41, a toxic compound to aquatic life with long-lasting effects. Under optimized cultural conditions (10.0-g L⁻¹ glucose, 0.2-g L⁻¹ yeast extract, and 1.0-g L⁻¹ (NH4)2SO4), the yeast strain was able to decolorize 97.86% of BB41 (50 mg L⁻¹) at pH 6 within 4 h of incubation at 30 °C under shaken conditions (12,238.00-μg h⁻¹ average decolorization rate) and 100% within 12 h. The UV-Vis spectral analysis, high-performance liquid chromatography (HPLC), and Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the complete decolorization and degradation of the BB41 dye by P. kudriavzevii CR-Y103. Also, other seven yeast strains, isolated from soil, as P. kudriavzevii (CR-Y108, CR-Y119, and CR-Y112), Candida tropicalis CR-Y128, Cyberlindnera saturnus CR-Y125, and Candida solani CR-Y124 have shown a promising decolorizing potential of azo-dye BB41 (99.89–76.09% decolorization). Phytotoxicity, cytotoxicity, and genotoxicity assays on Trifolium pratense and Triticum aestivum seedlings confirmed the high toxicity of BB41 dye (500 ppm), with inhibition on germination rate (%), root and shoot elongation, decreasing of mitoxic index value (with 34.03% in T. pratense and 40.25% in T. aestivum), and increasing the frequency of chromosomal aberrations (6.87 times in T. pratense and 6.25 times in T. aestivum), compared to control. The same biomarkers indicated the nontoxic nature of the BB41 degraded metabolite (500 ppm) obtained after P. kudriavzevii CR-Y103 treatment. Moreover, the healthy monkey kidney cells (Vero cells) had a low sensitivity to BB41 biodegraded products (250 μg mL⁻¹) (MTT cell viability assay) and revealed minor DNA damage (comet assay) compared to BB41 dye treatment. These findings show that P. kudriavzevii could be used in eco-friendly bioremediation technologies, applicable for reducing the toxicity of basic azo-dyes containing wastewaters.
View
Degradation and detoxification of azo dyes by a salt-tolerant yeast Cyberlindnera samutprakarnensis S4 under high-salt conditions
Article
Full-text available
  • Aug 2018
  • WORLD J MICROB BIOT
A new yeast strain which was capable of degrading various azo dyes under high-salt conditions was identified in this study. The results showed that the yeast named S4 was identified as Cyberlindnera samutprakarnensis through 26S rDNA sequence analysis and could decolorize more than 97% of Acid Red B (ARB) within 18 h under the optimal conditions. The acute toxicity of ARB sharply decreased after degradation. NADH–DCIP reductase and lignin peroxidase were determined as the key reductase and oxidase of the yeast S4, respectively. Furthermore, it was proposed that ARB was degraded by strain S4 successively through reduction of azo bonds, hydroxylation, deamination, desulfonation and finally to the TCA cycle.
View
Degradation of azo dye Acid Red 14 (AR14) from aqueous solution using H 2 O 2 /nZVI and S 2 O 8 2- /nZVI processes in the presence of UV irradiation
Article
  • Feb 2020
Azo dyes are mostly toxic and carcinogenic and cause harm to humans and the environment. This study was conducted to investigate the degradation of azo dye acid red 14 (AR14) from aqueous solution using hydrogen peroxide (H2O2)/nano zerovalent iron (nZVI) and persulfate (S2O82–)/nZVI processes in the presence of ultraviolet (UV) irradiation. This experimental study was carried out in a laboratory‐scale batch photoreactor with a useful volume of 1 L. The nZVI was synthesized by the sodium borohydride (NaBH4) reduction method. In these processes, the effects of parameters including initial pH, H2O2 concentration, S2O82– concentration, nZVI dose, concentration of AR14 dye, and reaction time were studied. The results showed that decolorization increased by increasing the nZVI dosage, H2O2 and S2O42‐ concentrations, and reaction time, or decreasing dye concentration and pH. However, a too high oxidant concentration (H2O2 and S2O42‐) could inhibit the degradation. The experimental conditions for degradation of AR14 by UV/S2O82‐/nZVI and UV/H2O2/nZVI processes were as follows: [H2O2] = 10 mM, [S2O82–] = 8 mM, AB14 dye = 100 mg/L, pH = 3, and nZVI dose = 0.05 g. Under these conditions, the highest removal efficiencies of AR14, chemical oxygen demand (COD), and total organic carbon (TOC) for the UV/S2O82–/nZVI process were 93.94%, 86.5%, and 81.6%, respectively, while these values were 89.3%, 79.57%, and 72.9% for the UV/H2O2/nZVI, respectively. Also, the average oxidation state (AOS) was decreased from 2.93 to 2.14 in the effluent of the UV/S2O82–/nZVI process and from 2.93 to 2.2 for the UV/H2O2/nZVI process. The results showed that the ratio of biochemical oxygen demand (BOD5) to COD in the effluents of the UV/S2O8²/nZVI and UV/H2O2/nZVI processes after 90 min was 0.63 and 0.74, respectively. These findings suggest biodegradability improvement. Practitioner points • Photocatalytic degradation of azo dye Acid Red 14 (AR14) was achieved using H2O2/nZVI and S2O82–/nZVI processes in the presence of UV irradiation. • Effects of operating parameters on photocatalytic degradation AR14 dye were evaluated in the UV/H2O2/nZVI and UV/S2O82–/nZVI processes. • Biodegradability and mineralization studies of AR14 dye photocatalytic degradation were performed for the UV/H2O2/nZVI and UV/S2O82–/nZVI processes.
View
Oerskovia paurometabola can efficiently decolorize azo dye Acid Red 14 and remove its recalcitrant metabolite
Article
  • Nov 2019
The biodegradation of dyes remains one of the biggest challenges of textile wastewater. Azo dyes are one of the most commonly employed dye classes, and biological treatment processes tend to generate recalcitrant aromatic amines, which are more toxic than the parent dye molecule. This study aimed to isolate bacterial strains with the capacity to degrade both the azo dye and the resulting aromatic amines towards the development of a simple and reliable treatment approach for dye-laden wastewaters. A mixed bacterial enrichment was first developed in an anaerobic-aerobic lab-scale sequencing batch reactor (SBR) fed with a synthetic textile wastewater containing the model textile azo dye Acid Red 14 (AR14). Eighteen bacterial strains were isolated from the SBR, including members of the Acinetobacter, Pseudomonas and Oerskovia genera, Oerskovia paurometabola presenting the highest decolorization capacity (91% after 24 h in static anaerobic culture). Growth assays supported that this is a facultative bacterium, and decolorization batch tests with 20-100 mg AR14 L-1 in a synthetic textile wastewater supplemented with yeast extract indicated that O. paurometabola has a high color removal capacity for a significant range of AR14 concentrations. In addition, a model typically used to describe biodegradation of xenobiotic compounds was adjusted to the results, to predict AR14 biodegradation time profiles at different initial concentrations. HPLC analysis confirmed that decolorization occurred through azo bond reduction under anaerobic conditions, the azo dye being completely reduced after 24 h of anaerobic incubation for the range of concentrations tested. Interestingly, partial (up to 63%) removal of one of the resulting aromatic amines (4-amino-naphthalene-1-sulfonic acid) was observed when subsequently subjected to aerobic conditions. Overall, this work showed the azo dye biodegradation potential of specific bacterial strains isolated from mixed culture bioreactors, reporting for the first time the decolorization capacity of an Oerskovia sp. with further biodegradation of a recalcitrant sulfonated aromatic amine metabolite.
View
Aerobic decolorization and detoxification of Acid Scarlet GR by a newly isolated salt-tolerant yeast strain Galactomyces geotrichum GG
Article
  • Nov 2019
  • INT BIODETER BIODEGR
Azo dyes are huge social and environmental hazards. Selective fungi are potential degraders for azo dyes and are of great significance to cleaning up and bioremediation. In this study, a salt-tolerant yeast strain GG with the ability to aerobically degrade and detoxify various azo dyes was isolated and identified as Galactomyces geotrichum. The optimal growth and decolorization parameters of strain GG were 0.1 g/L of yeast extract, 2.0 g/L of glucose, 0.4 g/L of ammonium sulfate, ≤ 40 g/L of NaCl, and pH values of 7.0–8.0. Under the optimal condition more than 92% of 100 mg/L of Acid Scarlet GR could be decolorized within 10 h by degradation, which was further confirmed by Fourier transform infrared spectroscopy. In addition, enzymatic analysis showed that the reductase NADH-DCIP and two oxidoreductases lignin peroxidase and laccase played the key roles in the degradation of Acid Scarlet GR, and the decolorization metabolites of Acid Scarlet GR exhibited much less toxicity than the parent dye by phytotoxicity assessment. The results improved the knowledge of azo-dye-decolorizing G. geotrichum species and provided efficient fungal resource for treatment of industrial wastewater containing azo dyes and salts.
View
View
Microbial degradation of azo dye Carmoisine in aqueous medium using Saccharomyces cerevisiae ATCC 9763
Article
  • Apr 2019
  • J HAZARD MATER
Carmoisine is an azo dye widely used in many industries, and therefore frequently occurs in the effluent of many factories. To our knowledge, biological degradation of carmoisine has received little attention. The present study investigates the capability of Saccharomyces cerevisiae ATCC 9763 for degradation of carmoisine. Spectrophotometry data indicates that carmoisine (50 mg/l) was eliminated from the aqueous medium after approximately 7 h of incubation with Saccharomyces under anaerobic shaking conditions. Thin layer chromatography (TLC) revealed the removal of carmoisine as well as the appearance of aromatic amines in samples collected from the decolourized medium by S. cerevisiae and this was subsequently confirmed by Fourier transform infrared (FTIR) spectroscopy. Liquid chromatography mass spectrometry (LC/MS) was carried out on fractions from consecutive column chromatography and two-dimensional (2D) chromatography. LC/MS indicated degradation of carmoisine into its constituent aromatic amines. In addition, investigating the effect of environmental conditions on the decolourization process indicated that yeast extract could positively affect decolourization rates; shaking significantly accelerated decolourization and shortened the time required for complete biodecolourization from ≃ 8 days to ≃ 7 h; and Saccharomyces was able to consume sucrose as a carbon source and remove the carmoisine despite the presence of sunset yellow, which remained unaffected.
View
Degradation of reactive green dye and textile effluent by Candida sp. VITJASS isolated from wetland paddy rhizosphere soil
Article
  • Aug 2018
Pollution by the release of dye containing wastewater has been alarming worldwide. Biodegradation of reactive green dye and textile effluent by Candida sp. VITJASS was investigated in dynamic condition. Paddy rhizosphere yeast Candida sp. VITJASS showed 84% removal of reactive green dye and 75% reduction in ADMI of textile effluent with a considerable synthesis of oxido-reductase enzymes. The degraded products were analyzed by UV-vis spectroscopy, HPLC and FTIR, which indicated the biotransformation of dye into non-toxic metabolites. GC-MS analysis revealed the formation of Diphenylmethane as potential end product. Phytotoxicity assessment on Phaseolus mungo seeds suggested the non- toxic nature of extracted metabolite. Toxicity studies on zebrafish revealed disturbed cellular integrity and disruption of tissues with crude dye supplementation. However, the degraded metabolites by VITJASS had an intact lumen morphology in the fishes. Thus, the present study depicts the augmentation of yeast strain to be efficacious and promising for degradation of dye with the synthesis of non-toxic metabolites.
View