scholarly journals Congo Red Decolorization and Detoxification by Aspergillus niger: Removal Mechanisms and Dye Degradation Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Nedra Asses ◽  
Lamia Ayed ◽  
Neila Hkiri ◽  
Moktar Hamdi

Congo red is one of the best known and used azo dyes which has two azo bonds (-N=N-) chromophore in its molecular structure. Its structural stability makes it highly toxic and resistant to biodegradation. The objective of this study was to assess the congo red biodegradation and detoxification by Aspergillus niger. The effects of pH, initial dye concentration, temperature, and shaking speed on the decolorization rate and enzymes production were studied. The maximum decolorization was correlated with lignin peroxidase and manganese peroxidase production. Above 97% were obtained when 2 g mycelia were incubated at pH 5, in presence of 200 mg/L of dye during 6 days at 28°C and under 120 to 150 rpm shaking speed. The degraded metabolites were characterized by using LC-MS/MS analyses and the biodegradation mechanism was also studied. Congo red bioconversion formed degradation metabolites mainly by peroxidases activities, i.e., the sodium naphthalene sulfonate (m/z = 227) and the cycloheptadienylium (m/z = 91). Phytotoxicity and microtoxicity tests confirmed that degradation metabolites were less toxic than original dye.

2021 ◽  
pp. 1-27
Author(s):  
Veena Sreedharan ◽  
Purbasha Saha ◽  
Kokati Venkata Bhaskara Rao

2018 ◽  
Vol 6 (4) ◽  
pp. 327-331
Author(s):  
Dipesh Shahi ◽  
Rajiv Sapkota

The use of different dyes and pigments is increasing with the increase in industrialization leading to the high production of effluent. The effluent contaminated with dyes and dye-stuff has harmful effects on public health and the environment. Thus, the treatment of effluent is essential. Biological approaches are gaining much interest due to their cost-effective and eco-friendly nature over various physicochemical methods for the treatment of dye-contaminated wastewater. This study highlights on the biodegradation of congo red and malachite green by using leaf and root extracts of Parthenium hysterophorus. The extract and the dye were mixed in the ratio of 1:2 and incubated at 40ºC for 90 minutes. Decolorization assay was performed using UV visible spectrophotometer which indicated that decolorization was due to degradation of dyes into non-colored metabolites. The leaves extract exhibited higher decolorizing activity than roots extract. The maximum decolorization for leaves extract was 55.8% (congo red) and 51.6% (malachite green). Furthermore, phytotoxicity test was carried out to determine the effect of dyes and their degradation metabolites on seed germination and seedling growth of chickpea (Cicer arietinum L). The germination percentage and seedling growth were more in degradation metabolites than untreated dyes, indicating less toxic nature of degradation metabolites. Hence, it can be inferred that P. hysterophorus extracts can be used to treat dye wastewater and treated wastewater can be used for irrigation. Int. J. Appl. Sci. Biotechnol. Vol 6(4): 327-331


2020 ◽  
Vol 128 (8) ◽  
pp. 1128
Author(s):  
Sefa Celik ◽  
A. Demet Demirag ◽  
Aysen E. Ozel ◽  
Sevim Akyuz

People have started to look for alternative sources because of the health problems created by petrochemical products used in all areas of human life and environmental problems that remain intact in nature for years. In this study, molecular structure analysis of cellulose triacetate II (CTA II) molecule, obtained from cellulose II and acetate, was carried out. There is an important relationship between the structure and activity of molecules, so it is very important to determine the geometric structure of a molecule. Therefore, using density functional theory (DFT) the most stable molecular geometries of the cellulose triacetate II monomer (C12H18O9) as well as dimer (C24H36O18), which included intermolecular H-bonding, were calculated. The analogous calculations were carried out for the (CTA-II)2 nano-cluster (C24H34O17), which represents the local structure of CTA-II crystal, and created by binding the two most stable CTA II molecules by covalent bond. Scaled wavenumbers and potential energy distribution of the vibrational modes of CTA monomer and (CTA-II)2 nano-cluster were computed. In order to evaluate the interaction of CTA II with the Aspergillus niger cellulase enzyme,which is an important that is active in cellulose digestion and CTA II, molecular docking studies were carried out. H-binding interactions between CTA II (in monomeric, dimeric and cluster forms) and the active site of the Aspergillus niger cellulase enzyme were shown. Moreover, in silico ADMET prediction study was calculated for CTA-II monomer to predict its druglikeness properties. Keywords: Cellulose triacetate II, Density Function Theory, IR-ATR, cluster for.


Author(s):  
Veena Gayathri Krishnaswamy

The limited availability of fresh water is a global crisis. The growing consumption of fresh water due to anthropogenic activities has taken its toll on available water resources. Unfortunately, water bodies are still used as sinks for waste water from domestic and industrial sources. Azo dyes account for the majority of all dye stuffs, produced because they are extensively used in the textile, paper, food, leather, cosmetics, and pharmaceutical industries. Bacterial degradation of azo dyes under certain environmental conditions has gained momentum as a method of treatment, as these are inexpensive, eco-friendly, and can be applied to wide range of such complex dyes. The enzymatic approach has attracted much interest with regard to degradation of azo dyes from wastewater. The oxido-reductive enzymes are responsible for generating highly reactive free radicals that undergo complex series of spontaneous cleavage reactions, due to the susceptibility of enzymes to inactivation in the presence of the other chemicals. The oxidoreductive enzymes, such as lignin peroxidase, laccases, tyrosinase, azoreductase, riboflavin reductive, polyphenol oxidase, and aminopyrine n-demethylase, have been mainly utilized in the bacterial degradation of azo dye. Along with the reductive enzymes, some investigators have demonstrated the involvement in some other enzymes, such as Lignin peroxides and other enzymes. This chapter reviews the importance of enzymes in dye degradation.


2000 ◽  
Vol 66 (7) ◽  
pp. 3016-3023 ◽  
Author(s):  
Ana Conesa ◽  
Cees A. M. J. J. van den Hondel ◽  
Peter J. Punt

ABSTRACT To get insight into the limiting factors existing for the efficient production of fungal peroxidase in filamentous fungi, the expression of the Phanerochaete chrysosporium lignin peroxidase H8 (lipA) and manganese peroxidase (MnP) H4 (mnp1) genes in Aspergillus niger has been studied. For this purpose, a protease-deficient A. niger strain and different expression cassettes have been used. Northern blotting experiments indicated high steady-state mRNA levels for the recombinant genes. Manganese peroxidase was secreted into the culture medium as an active protein. The recombinant protein showed specific activity and a spectrum profile similar to those of the native enzyme, was correctly processed at its N terminus, and had a slightly lower mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Recombinant MnP production could be increased up to 100 mg/liter upon hemoglobin supplementation of the culture medium. Lignin peroxidase was also secreted into the extracellular medium, although the protein was not active, presumably due to incorrect processing of the secreted enzyme. Expression of the lipA and mnp1 genes fused to the A. niger glucoamylase gene did not result in improved production yields.


RSC Advances ◽  
2016 ◽  
Vol 6 (5) ◽  
pp. 3592-3599 ◽  
Author(s):  
Ming Chen ◽  
Xiaosheng Qin ◽  
Jian Li ◽  
Guangming Zeng

Increasing evidence has shown that carbon nanotubes (CNTs) present adverse effects on the environment and human health, which stresses the importance of exploring CNT biodegradation.


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