From organic pollutants to bioplastics: insights into the bioremediation of aromatic compounds by Cupriavidus necator

Coagulation is one of the most important physicochemical treatment steps in industrial wastewater to reduce the suspended and colloidal materials responsible for colour and turbidity of the wastewater. The manufacturing plant of N,N′-Dichloro bis (2,4,6-trichlorophenyl) urea (CC2) produces wastewater containing pyridine, acetic acid and diphenyl urea (DPU). The wastewater also contains lot of suspended solids like CC2 and various poly-aromatic compounds. In our present investigation, our basic aim was to find an effective coagulation process for the pretreatment of wastewater discharged from the CC2 plant. Studies were conducted to find out a suitable and effective coagulant for pretreatment of this wastewater. Various coagulating agents such as alum, ferric chloride, sodium carboxymethyl cellulose (Na-CMC) were used. Alum was found to be the most effective coagulant. Coagulation of the wastewater resulted in the total suspended solids (TSS) removal in the range of 92–94% and chemical oxygen demand (COD) removal in the range of 59 to 65% at a dose of 500 mg L−1 of alum at a pH ≥ 7.0. After coagulation the concentration of pyridine in wastewater was found to be reduced by 10.0% and that of DPU 40–45% with a dosage of 500 mg L−1 alum.

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Genuine genetic redundancy in maleylacetate-reductase-encoding genes involved in degradation of haloaromatic compounds by Cupriavidus necator JMP134

Microbiology ◽

10.1099/mic.0.032086-0 ◽

2009 ◽

Vol 155 (11) ◽

pp. 3641-3651 ◽

Cited By ~ 14

Author(s):

Danilo Pérez-Pantoja ◽

Raúl A. Donoso ◽

Miguel A. Sánchez ◽

Bernardo González

Keyword(s):

Aromatic Compounds ◽

Gene Clusters ◽

Cupriavidus Necator ◽

Gene Products ◽

Genetic Redundancy ◽

Rt Pcr ◽

Cell Extracts ◽

Maleylacetate Reductase ◽

Encoding Genes

Maleylacetate reductases (MAR) are required for biodegradation of several substituted aromatic compounds. To date, the functionality of two MAR-encoding genes (tfdF I and tfdF II) has been reported in Cupriavidus necator JMP134(pJP4), a known degrader of aromatic compounds. These two genes are located in tfd gene clusters involved in the turnover of 2,4-dichlorophenoxyacetate (2,4-D) and 3-chlorobenzoate (3-CB). The C. necator JMP134 genome comprises at least three other genes that putatively encode MAR (tcpD, hqoD and hxqD), but confirmation of their functionality and their role in the catabolism of haloaromatic compounds has not been assessed. RT-PCR expression analyses of C. necator JMP134 cells exposed to 2,4-D, 3-CB, 2,4,6-trichlorophenol (2,4,6-TCP) or 4-fluorobenzoate (4-FB) showed that tfdF I and tfdF II are induced by haloaromatics channelled to halocatechols as intermediates. In contrast, 2,4,6-TCP only induces tcpD, and any haloaromatic compounds tested did not induce hxqD and hqoD. However, the tcpD, hxqD and hqoD gene products showed MAR activity in cell extracts and provided the MAR function for 2,4-D catabolism when heterologously expressed in MAR-lacking strains. Growth tests for mutants of the five MAR-encoding genes in strain JMP134 showed that none of these genes is essential for degradation of the tested compounds. However, the role of tfdF I/tfdF II and tcpD genes in the expression of MAR activity during catabolism of 2,4-D and 2,4,6-TCP, respectively, was confirmed by enzyme activity tests in mutants. These results reveal a striking example of genetic redundancy in the degradation of aromatic compounds.

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Vehicle washing as a source of organic pollutants in municipal wastewater

Water Science & Technology ◽

10.2166/wst.1996.0075 ◽

1996 ◽

Vol 33 (6) ◽

pp. 1-8 ◽

Cited By ~ 11

Author(s):

Nicklas Paxéus

Keyword(s):

Organic Pollutants ◽

Aromatic Compounds ◽

Municipal Wastewater ◽

Material Balance ◽

Dust Particles ◽

Glycol Ethers ◽

Balance Study ◽

Total Load ◽

Volatile Hydrocarbons ◽

Polycyclic Aromatic

Effluent wastewaters from a large number of automatic vehicle washing facilities in Göteborg have been analysed for conventional parameters (COD, oil content) and for individual organic pollutants using GC-MS. The identified pollutants encompassed short-chain paraffins, substituted benzenes, glycol ethers, phthalates, adipate, tributyl phosphate, bi- and polycyclic aromatic compounds and nonylphenol. While the volatile hydrocarbons, ethers and nonylphenol were discharged through the use of petroleum based degreasing formulations and washing agents, dirt/dust particles and traffic grime contributed to a large extent to the origin of bicyclic aromatic compounds, PAH's and phthalates in the effluent wastewater. A material balance study did not show the elimination of the organic pollutants in the oil separator, probably due to the formation of stable emulsions. Although the wastewaters from vehicle washing facilities exhibited a relatively high content of organic pollutants their estimated contribution to the total load on the municipal sewer in Göteborg was, with the exception of naphthalene, very low.

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Synthetic Approaches, Modification Strategies and the Application of Quantum Dots in the Sensing of Priority Pollutants

Applied Sciences ◽

10.3390/app112411580 ◽

2021 ◽

Vol 11 (24) ◽

pp. 11580

Author(s):

Rodney Maluleke ◽

Oluwatobi Samuel Oluwafemi

Keyword(s):

Quantum Dots ◽

Polycyclic Aromatic Hydrocarbons ◽

Organic Pollutants ◽

Aromatic Hydrocarbons ◽

Aromatic Compounds ◽

Water Soluble ◽

Sensing Applications ◽

Wide Range ◽

Polycyclic Aromatic ◽

Nitro Aromatic

Polycyclic aromatic hydrocarbons (PAHs) and nitro-aromatic compounds (NACs) are two classifications of environmental pollutants that have become a source of health concerns. As a result, there have been several efforts towards the development of analytical methods that are efficient and affordable that can sense these pollutants. In recent decades, a wide range of techniques has been developed for the detection of pollutants present in the environment. Among these different techniques, the use of semiconductor nanomaterials, also known as quantum dots, has continued to gain more attention in sensing because of the optical properties that make them useful in the identification and differentiation of pollutants in water bodies. Reported studies have shown great improvement in the sensing of these pollutants. This review article starts with an introduction on two types of organic pollutants, namely polycyclic aromatic hydrocarbons and nitro-aromatic explosives. This is then followed by different quantum dots used in sensing applications. Then, a detailed discussion on different groups of quantum dots, such as carbon-based quantum dots, binary and ternary quantum dots and quantum dot composites, and their application in the sensing of organic pollutants is presented. Different studies on the comparison of water-soluble quantum dots and organic-soluble quantum dots of a fluorescence sensing mechanism are reviewed. Then, different approaches on the improvement of their sensitivity and selectivity in addition to challenges associated with some of these approaches are also discussed. The review is concluded by looking at different mechanisms in the sensing of polycyclic aromatic hydrocarbons and nitro-aromatic compounds.

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Transcriptome differences between Cupriavidus necator NH9 grown with 3-chlorobenzoate and that grown with benzoate

10.21203/rs.3.rs-50641/v3 ◽

2020 ◽

Author(s):

Ryota Moriuchi ◽

Hideo Dohra ◽

Yu Kanesaki ◽

Naoto Ogawa

Keyword(s):

Aromatic Compounds ◽

Differential Expression Analysis ◽

Agar Plate ◽

Enrichment Analysis ◽

Cupriavidus Necator ◽

Major Facilitator Superfamily ◽

Bacterial Degradation ◽

Genes Encoding ◽

Chlorinated Aromatic Compounds ◽

Major Facilitator

Abstract BackgroundAromatic compounds derived from human activities are often released into the environment. Many of them, especially halogenated aromatics, are persistent in nature and pose threats to organisms. Therefore, the microbial degradation of these compounds has been studied intensively. Our laboratory has studied the expression of genes in Cupriavidus necator NH9 involved in the degradation of 3-chlorobenzoate (3-CB), a model compound for studies on bacterial degradation of chlorinated aromatic compounds. In this study aimed at exploring how this bacterium has adapted to the utilization of chlorinated aromatic compounds, we performed RNA-seq analysis of NH9 cells cultured with 3-CB, benzoate (BA), or citric acid (CA). The purpose of these analyses was to identify differentially expressed genes encoding products with various biological functions involved in the degradation of 3-CB and BA.ResultsDifferential expression analysis confirmed strong induction of genes encoding enzymes in degradation pathways of 3-CB and BA, including benABCD (more than 256-fold compared with CA) encoding benzoate 1,2-dioxygenase involved in initial hydroxylation of both 3-CB and BA, and cbnABCD (more than 200-fold compared with BA and CA) encoding enzymes of chlorocatechol ortho-cleavage pathway. Four genes encoding major facilitator superfamily transporters were specifically induced by 3-CB or BA, and one cluster of genes encoding components of the ATP-binding cassette transporter system was significantly induced by 3-CB. Stress response genes encoding chaperones, proteases, the phosphate transporter PstBACS, and superoxide oxidase were upregulated in response to 3-CB and/or BA. Gene Ontology enrichment analysis revealed that genes encoding dioxygenases were upregulated by both 3-CB and BA. Intriguingly, the “cell motility,” “signal transduction,” and “chemotaxis” terms were significantly upregulated by BA compared with 3-CB. Consistent with this, in semi-solid agar plate assays, NH9 cells showed stronger chemotaxis to BA than to 3-CB.ConclusionsOur results showed that the chemotaxis behavior of NH9 differs between 3-CB and BA. We inferred that NH9 has not fully adapted to the utilization of chlorinated benzoate, unlike its analogous aromatic compound BA, in nature.

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Transcriptome differences between Cupriavidus necator NH9 grown with 3-chlorobenzoate and that grown with benzoate

10.21203/rs.3.rs-50641/v2 ◽

2020 ◽

Author(s):

Ryota Moriuchi ◽

Hideo Dohra ◽

Yu Kanesaki ◽

Naoto Ogawa

Keyword(s):

Aromatic Compounds ◽

Differential Expression Analysis ◽

Agar Plate ◽

Enrichment Analysis ◽

Cupriavidus Necator ◽

Major Facilitator Superfamily ◽

Bacterial Degradation ◽

Genes Encoding ◽

Chlorinated Aromatic Compounds ◽

Major Facilitator

Abstract Background Aromatic compounds derived from human activities are often released into the environment. Many of them, especially halogenated aromatics, are persistent in nature and pose threats to organisms. Therefore, the microbial degradation of these compounds has been studied intensively. Our laboratory has studied the expression of genes in Cupriavidus necator NH9 involved in the degradation of 3-chlorobenzoate (3-CB), a model compound for studies on bacterial degradation of chlorinated aromatic compounds. In this study aimed at exploring how this bacterium has adapted to the utilization of chlorinated aromatic compounds, we performed RNA-seq analysis of NH9 cells cultured with 3-CB, benzoate (BA), or citric acid (CA). The purpose of these analyses was to identify differentially expressed genes encoding products with various biological functions involved in the degradation of 3-CB and BA. Results Differential expression analysis confirmed strong induction of genes encoding enzymes in degradation pathways of 3-CB and BA, including benABCD (more than 256-fold compared with CA) encoding benzoate 1,2-dioxygenase involved in initial hydroxylation of both 3-CB and BA, and cbnABCD (more than 200-fold compared with BA and CA) encoding enzymes of chlorocatechol ortho -cleavage pathway. Four genes encoding major facilitator superfamily transporters were specifically induced by 3-CB or BA, and one cluster of genes encoding components of the ATP-binding cassette transporter system was significantly induced by 3-CB. Stress response genes encoding chaperones, proteases, the phosphate transporter PstBACS, and superoxide oxidase were upregulated in response to 3-CB and/or BA. Gene Ontology enrichment analysis revealed that genes encoding dioxygenases were upregulated by both 3-CB and BA. Intriguingly, the “cell motility,” “signal transduction,” and “chemotaxis” terms were significantly upregulated by BA compared with 3-CB. Consistent with this, in semi-solid agar plate assays, NH9 cells showed stronger chemotaxis to BA than to 3-CB. Conclusions Our results showed that the chemotaxis behavior of NH9 differs between 3-CB and BA. We inferred that NH9 has not fully adapted to the utilization of chlorinated benzoate, unlike its analogous aromatic compound BA, in nature.

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Transcriptome differences between Cupriavidus necator NH9 grown with 3-chlorobenzoate and that grown with benzoate

10.21203/rs.3.rs-50641/v1 ◽

2020 ◽

Author(s):

Ryota Moriuchi ◽

Hideo Dohra ◽

Yu Kanesaki ◽

Naoto Ogawa

Keyword(s):

Aromatic Compounds ◽

Differential Expression Analysis ◽

Agar Plate ◽

Enrichment Analysis ◽

Cupriavidus Necator ◽

Bacterial Degradation ◽

Expression Of Genes ◽

Genes Encoding ◽

Chlorinated Aromatic Compounds ◽

Semi Solid

Abstract Background Aromatic compounds derived from human activities are often released into the environment. Many of them, especially halogenated aromatics, are persistent in nature and pose threats to organisms. Therefore, the microbial degradation of these compounds has been studied intensively. Our laboratory has studied the expression of genes in Cupriavidus necator NH9 involved in the degradation of 3-chlorobenzoate (3-CB), a model compound for studies on bacterial degradation of chlorinated aromatic compounds. In this study aimed at exploring how this bacterium has adapted to the utilization of chlorinated aromatic compounds, we performed RNA-seq analysis of NH9 cells cultured with 3-CB, benzoate (BA), or citric acid. The purpose of these analyses was to identify differentially expressed genes encoding products with various biological functions involved in the degradation of 3-CB and BA. Results Differential expression analysis confirmed strong induction of genes encoding enzymes in degradation pathways of 3-CB and BA (benABCD, cbnABCD, catA, catB, catDC, pcaIJF, and boxABCD). Genes involved in the degradation of 3-hydroxybenzoate and anthranilate were upregulated by 3-CB but not by BA, suggesting that transcriptional regulators of these degradative genes recognized 3-CB (or its intermediate metabolite) as an inducer. Four genes encoding MFS transporters were specifically induced by 3-CB or BA, and one cluster of genes encoding components of the ABC transporter system was significantly induced by 3-CB. Stress response genes encoding chaperones, proteases, the phosphate transporter PstBACS, and superoxide oxidase were upregulated in response to 3-CB and/or BA. Gene Ontology enrichment analysis revealed that genes encoding dioxygenases were upregulated by both 3-CB and BA. Intriguingly, the “cell motility,” “signal transduction,” and “chemotaxis” terms were significantly upregulated by BA compared with 3-CB. Consistent with this, in semi-solid agar plate assays, NH9 cells showed stronger chemotaxis to BA than to 3-CB. Conclusions Our results showed that the chemotaxis behavior of NH9 differs between 3-CB and BA. We inferred that NH9 has not fully adapted to the utilization of chlorinated benzoate, unlike its analogous aromatic compound BA, in nature.

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The Correlation Pattern of Fly Ash Components: Chromium as a Potential Catalyst in the Thermal Formation of Chlorinated Aromatic Compounds

Environmental Chemistry ◽

10.1071/en04016 ◽

2004 ◽

Vol 1 (1) ◽

pp. 18 ◽

Cited By ~ 3

Author(s):

Tomas Öberg ◽

Tomas Öhrström ◽

Jan Bergström

Keyword(s):

Fly Ash ◽

Organic Pollutants ◽

Aromatic Compounds ◽

Catalytic Effect ◽

Chlorinated Phenols ◽

Correlation Pattern ◽

Aromatic Molecules ◽

Chemical Agents ◽

Chlorinated Aromatic Compounds

Environmental Context.Harmful chlorinated aromatic molecules are often formed and released into the environment during incineration of municipal waste and other waste fuels. This is a problem that has been known since the 1970s, and while efforts are being made to reduce these emissions, these persistent organic pollutants are still subsequently released into the environment, with residues and emissions to the atmosphere. In an attempt to uncover the chemical agents responsible for the formation of these pollutants, this study reveals that chromium, a commonly encountered metal, could be an important factor. Abstract.Chlorinated aromatic compounds are unintentionally released from combustion sources into the environment. This thermal formation is catalyzed by fly ash components and much interest has been focussed on the role of copper. This study report results from a series of 16 full-scale trials with different fuel compositions. The correlation pattern of fly ash components seem to suggest that the catalytic effect may be due also to other metal oxychlorination catalysts. Chromium shows particularly strong and statistically significant correlations with many of the chlorinated phenols, benzenes, dibenzo-p-dioxins (PCDDs), and dibenzofurans (PCDFs).

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