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Yang L, Pang S, Zhou J, Li X, Yao M, Xia S. Biological reduction and hydrodechlorination of chlorinated nitroaromatic antibiotic chloramphenicol under H 2-transfer membrane biofilm reactor. BIORESOURCE TECHNOLOGY 2023; 376:128881. [PMID: 36921636 DOI: 10.1016/j.biortech.2023.128881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/04/2023] [Accepted: 03/09/2023] [Indexed: 06/18/2023]
Abstract
Chlorinated nitroaromatic antibiotic chloramphenicol (CAP) is a persistent pollutant that is widely present in environments. A H2 transfer membrane biofilm reactor (H2-MBfR) and short-term batch tests were setup to investigate the co-removal of CAP and NO3-. Results showed that the presence of CAP (<10 mg L-1) has no effect on the denitrification process while 100% removal efficiency of CAP can be obtained when nitrate was absent. Nitroaromatic reduction and completely dechlorination were successfully realized when CAP was removed. The CAP transformation product p-aminobenzoic acid (PABA) was detected and batch tests revealed that the hydroxy carboxylation was far faster than nitroaromatic reduction when p-nitrobenzyl alcohol (PNBOH) was conversed to p-aminobenzoic acid (PABA). The path way of CAP degradation was proposed based on the intermediate's analysis. Microbial community analysis indicated that Pleomorphomonadaceae accounts for the dechlorination of CAP.
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Affiliation(s)
- Lin Yang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Si Pang
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Jingzhou Zhou
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Xiaodi Li
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Mengying Yao
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
| | - Siqing Xia
- State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China.
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Molina L, Segura A, Duque E, Ramos JL. The versatility of Pseudomonas putida in the rhizosphere environment. ADVANCES IN APPLIED MICROBIOLOGY 2019; 110:149-180. [PMID: 32386604 DOI: 10.1016/bs.aambs.2019.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This article addresses the lifestyle of Pseudomonas and focuses on how Pseudomonas putida can be used as a model system for biotechnological processes in agriculture, and in the removal of pollutants from soils. In this chapter we aim to show how a deep analysis using genetic information and experimental tests has helped to reveal insights into the lifestyle of Pseudomonads. Pseudomonas putida is a Plant Growth Promoting Rhizobacteria (PGPR) that establishes commensal relationships with plants. The interaction involves a series of functions encoded by core genes which favor nutrient mobilization, prevention of pathogen development and efficient niche colonization. Certain Pseudomonas putida strains harbor accessory genes that confer specific biodegradative properties and because these microorganisms can thrive on the roots of plants they can be exploited to remove pollutants via rhizoremediation, making the consortium plant/Pseudomonas a useful tool to combat pollution.
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Affiliation(s)
- Lázaro Molina
- CSIC- Estación Experimental del Zaidín, Granada, Spain
| | - Ana Segura
- CSIC- Estación Experimental del Zaidín, Granada, Spain
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Zhang CL, Yu YY, Fang Z, Naraginti S, Zhang Y, Yong YC. Recent advances in nitroaromatic pollutants bioreduction by electroactive bacteria. Process Biochem 2018. [DOI: 10.1016/j.procbio.2018.04.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Liao HY, Chien CC, Tang P, Chen CC, Chen CY, Chen SC. The integrated analysis of transcriptome and proteome for exploring the biodegradation mechanism of 2, 4, 6-trinitrotoluene by Citrobacter sp. JOURNAL OF HAZARDOUS MATERIALS 2018; 349:79-90. [PMID: 29414755 DOI: 10.1016/j.jhazmat.2018.01.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 01/16/2018] [Accepted: 01/21/2018] [Indexed: 06/08/2023]
Abstract
Citrobacter sp. has been shown to degrade 2,4,6-trinitrotoluene (TNT). However, the mechanism of its TNT biodegradation is poorly understood. An integrated proteome and transcriptome analysis was performed for investigating the differential genes and differential proteins in bacterial growth at the onset of experiments and after 12 h treatment with TNT. With the RNA sequencing, we found a total of 3792 transcripts and 569 differentially expressed genes (≥2 fold, P < 0.05) by. Genes for amino acid transport, cellular metabolism and stress-shock proteins were up-regulated, while carbohydrate transport and metabolism were down-regulated. A total of 42 protein spots (≥1.5 fold, P < 0.05) showed differential expression on two-dimensional gel electrophoresis and these proteins were identified by mass spectrometry. The most prominent proteins up-regulated were involved in energy production and conversion, amino acid transport and metabolism, posttranslational modification, protein turnover and chaperones. Proteins involved in carbohydrate transport and metabolism were down-regulated. Most notably, we observed that nemA encoding N-ethylmaleimide reductase was the most up-regulated gene involved in TNT degradation, and further proved that it can transform TNT to 4-amino-2,6-dinitrotoluene (4-ADNT) and 2-amino-4,6-dinitrotoluene (2-ADNT). This study highlights the molecular mechanisms of Citrobacter sp. for TNT removal.
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Affiliation(s)
- Hung-Yu Liao
- Department of Life Sciences, National Central University, No. 300, Jhing-da Rd., Jhongli City, Taoyuan, 32001, Taiwan
| | - Chih-Ching Chien
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, No. 135, Yuantung Rd., Jhongli City, Taoyuan, 32003, Taiwan
| | - Petrus Tang
- Department of Parasitology, Chang Gung University, No.259, Wenhua 1st Rd., Guishan Dis., Taoyuan City, 33302, Taiwan
| | - Chien-Cheng Chen
- Department of Biotechnology, National Kaohsiung Normal University, No.116, Heping 1st Rd., Lingya District, Kaohsiung City, 80201, Taiwan
| | - Chin-Yu Chen
- Department of Life Sciences, National Central University, No. 300, Jhing-da Rd., Jhongli City, Taoyuan, 32001, Taiwan
| | - Ssu-Ching Chen
- Department of Life Sciences, National Central University, No. 300, Jhing-da Rd., Jhongli City, Taoyuan, 32001, Taiwan.
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Avila-Arias H, Avellaneda H, Garzón V, Rodríguez G, Arbeli Z, Garcia-Bonilla E, Villegas-Plazas M, Roldan F. Screening for biosurfactant production by 2,4,6-trinitrotoluene-transforming bacteria. J Appl Microbiol 2017; 123:401-413. [DOI: 10.1111/jam.13504] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 05/18/2017] [Accepted: 05/25/2017] [Indexed: 11/28/2022]
Affiliation(s)
- H. Avila-Arias
- Unidad de Saneamiento y Biotecnología Ambiental (USBA); Departamento de Biología; Facultad de Ciencias; Pontificia Universidad Javeriana; Bogotá Colombia
| | - H. Avellaneda
- Unidad de Saneamiento y Biotecnología Ambiental (USBA); Departamento de Biología; Facultad de Ciencias; Pontificia Universidad Javeriana; Bogotá Colombia
| | - V. Garzón
- Unidad de Saneamiento y Biotecnología Ambiental (USBA); Departamento de Biología; Facultad de Ciencias; Pontificia Universidad Javeriana; Bogotá Colombia
| | - G. Rodríguez
- Unidad de Saneamiento y Biotecnología Ambiental (USBA); Departamento de Biología; Facultad de Ciencias; Pontificia Universidad Javeriana; Bogotá Colombia
| | - Z. Arbeli
- Unidad de Saneamiento y Biotecnología Ambiental (USBA); Departamento de Biología; Facultad de Ciencias; Pontificia Universidad Javeriana; Bogotá Colombia
| | - E. Garcia-Bonilla
- Unidad de Saneamiento y Biotecnología Ambiental (USBA); Departamento de Biología; Facultad de Ciencias; Pontificia Universidad Javeriana; Bogotá Colombia
| | - M. Villegas-Plazas
- Unidad de Saneamiento y Biotecnología Ambiental (USBA); Departamento de Biología; Facultad de Ciencias; Pontificia Universidad Javeriana; Bogotá Colombia
| | - F. Roldan
- Unidad de Saneamiento y Biotecnología Ambiental (USBA); Departamento de Biología; Facultad de Ciencias; Pontificia Universidad Javeriana; Bogotá Colombia
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Liang SH, Hsu DW, Lin CY, Kao CM, Huang DJ, Chien CC, Chen SC, Tsai IJ, Chen CC. Enhancement of microbial 2,4,6-trinitrotoluene transformation with increased toxicity by exogenous nutrient amendment. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2017; 138:39-46. [PMID: 28006730 DOI: 10.1016/j.ecoenv.2016.12.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/18/2016] [Accepted: 12/08/2016] [Indexed: 06/06/2023]
Abstract
In this study, the bacterial strain Citrobacter youngae strain E4 was isolated from 2,4,6-trinitrotoluene (TNT)-contaminated soil and used to assess the capacity of TNT transformation with/without exogenous nutrient amendments. C. youngae E4 poorly degraded TNT without an exogenous amino nitrogen source, whereas the addition of an amino nitrogen source considerably increased the efficacy of TNT transformation in a dose-dependent manner. The enhanced TNT transformation of C. youngae E4 was mediated by increased cell growth and up-regulation of TNT nitroreductases, including NemA, NfsA and NfsB. This result indicates that the increase in TNT transformation by C. youngae E4 via nitrogen nutrient stimulation is a cometabolism process. Consistently, TNT transformation was effectively enhanced when C. youngae E4 was subjected to a TNT-contaminated soil slurry in the presence of an exogenous amino nitrogen amendment. Thus, effective enhancement of TNT transformation via the coordinated inoculation of the nutrient-responsive C. youngae E4 and an exogenous nitrogen amendment might be applicable for the remediation of TNT-contaminated soil. Although the TNT transformation was significantly enhanced by C. youngae E4 in concert with biostimulation, the 96-h LC50 value of the TNT transformation product mixture on the aquatic invertebrate Tigriopus japonicas was higher than the LC50 value of TNT alone. Our results suggest that exogenous nutrient amendment can enhance microbial TNT transformation; however, additional detoxification processes may be needed due to the increased toxicity after reduced TNT transformation.
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Affiliation(s)
- Shih-Hsiung Liang
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Duen-Wei Hsu
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Chia-Ying Lin
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Chih-Ming Kao
- Institute of Environmental Engineering, National Sun Yat-sen University, Kaohsiung, Taiwan
| | - Da-Ji Huang
- Department of Environmental Resources Management, Chia Nan University of Pharmacy & Science, Tainan, Taiwan
| | - Chih-Ching Chien
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Chung-Li, Taiwan
| | - Ssu-Ching Chen
- Department of Life Sciences, National Central University, Taoyuan, Taiwan
| | | | - Chien-Cheng Chen
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan.
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7
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Draft Genome Sequence of Pseudomonas putida JLR11, a Facultative Anaerobic 2,4,6-Trinitrotoluene Biotransforming Bacterium. GENOME ANNOUNCEMENTS 2015; 3:3/5/e00904-15. [PMID: 26337875 PMCID: PMC4559724 DOI: 10.1128/genomea.00904-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We report the draft genome sequence of Pseudomonas putida JLR11, a facultative anaerobic bacterium that has been studied in detail for its capacity to use the explosive 2,4,6-trinitrotoluene (TNT) as a nitrogen source. The sequence confirms the mechanisms used by this versatile strain to reduce and assimilate nitrogen from TNT.
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Stenuit BA, Agathos SN. Microbial 2,4,6-trinitrotoluene degradation: could we learn from (bio)chemistry for bioremediation and vice versa? Appl Microbiol Biotechnol 2010; 88:1043-64. [DOI: 10.1007/s00253-010-2830-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 08/06/2010] [Accepted: 08/08/2010] [Indexed: 12/11/2022]
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Abstract
Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed.
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Affiliation(s)
- Kou-San Ju
- Department of Microbiology, University of California, Davis, California 95616
| | - Rebecca E. Parales
- Department of Microbiology, University of California, Davis, California 95616
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Wittich RM, Ramos JL, van Dillewijn P. Microorganisms and explosives: mechanisms of nitrogen release from TNT for use as an N-source for growth. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:2773-2776. [PMID: 19475948 DOI: 10.1021/es803372n] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Unstable reduced derivatives of 2,4,6-trinitrotoluene (TNT) produced by microorganisms have been found to release nitrite by rearomatization and/or condensation. Here, we present further information regarding the novel mechanism of the condensation of reactive hydroxylaminodinitrotoluene and the Meisenheimer dihydride complex of TNT to produce two secondary diarylamine isomers. Using uniformly 15N-labeled (15N3) TNT, we show that the nitrite is being released by the condensation reaction and, also under environmental conditions, will originate from the microbiologically generated dihydride complex.
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Affiliation(s)
- Rolf-Michael Wittich
- Departamento de Protección Ambiental, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Calle Profesor Albareda 1, E-18008 Granada, Spain.
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11
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Subfunctionality of hydride transferases of the old yellow enzyme family of flavoproteins of Pseudomonas putida. Appl Environ Microbiol 2008; 74:6703-8. [PMID: 18791012 DOI: 10.1128/aem.00386-08] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To investigate potential complementary activities of multiple enzymes belonging to the same family within a single microorganism, we chose a set of Old Yellow Enzyme (OYE) homologs of Pseudomonas putida. The physiological function of these enzymes is not well established; however, an activity associated with OYE family members from different microorganisms is their ability to reduce nitroaromatic compounds. Using an in silico approach, we identified six OYE homologs in P. putida KT2440. Each gene was subcloned into an expression vector, and each corresponding gene product was purified to homogeneity prior to in vitro analysis for its catalytic activity against 2,4,6-trinitrotoluene (TNT). One of the enzymes, called XenD, lacked in vitro activity, whereas the other five enzymes demonstrated type I hydride transferase activity and reduced the nitro groups of TNT to hydroxylaminodinitrotoluene derivatives. XenB has the additional ability to reduce the aromatic ring of TNT to produce Meisenheimer complexes, defined as type II hydride transferase activity. The condensations of the primary products of type I and type II hydride transferases react with each other to yield diarylamines and nitrite; the latter can be further reduced to ammonium and serves as a nitrogen source for microorganisms in vivo.
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Type II hydride transferases from different microorganisms yield nitrite and diarylamines from polynitroaromatic compounds. Appl Environ Microbiol 2008; 74:6820-3. [PMID: 18791007 DOI: 10.1128/aem.00388-08] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Homogenous preparations of XenB of Pseudomonas putida, pentaerythritol tetranitrate reductase of Enterobacter cloacae, and N-ethylmaleimide reductase of Escherichia coli, all type II hydride transferases of the Old Yellow Enzyme family of flavoproteins, are shown to reduce the polynitroaromatic compound 2,4,6-trinitrotoluene (TNT). The reduction of this compound yields hydroxylaminodinitrotoluenes and Meisenheimer dihydride complexes, which, upon condensation, yield stoichiometric amounts of nitrite and diarylamines, implying that type II hydride transferases are responsible for TNT denitration, a process with important environmental implications for TNT remediation.
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Roldán MD, Pérez-Reinado E, Castillo F, Moreno-Vivián C. Reduction of polynitroaromatic compounds: the bacterial nitroreductases. FEMS Microbiol Rev 2008; 32:474-500. [PMID: 18355273 DOI: 10.1111/j.1574-6976.2008.00107.x] [Citation(s) in RCA: 288] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Most nitroaromatic compounds are toxic and mutagenic for living organisms, but some microorganisms have developed oxidative or reductive pathways to degrade or transform these compounds. Reductive pathways are based either on the reduction of the aromatic ring by hydride additions or on the reduction of the nitro groups to hydroxylamino and/or amino derivatives. Bacterial nitroreductases are flavoenzymes that catalyze the NAD(P)H-dependent reduction of the nitro groups on nitroaromatic and nitroheterocyclic compounds. Nitroreductases have raised a great interest due to their potential applications in bioremediation, biocatalysis, and biomedicine, especially in prodrug activation for chemotherapeutic cancer treatments. Different bacterial nitroreductases have been purified and their biochemical and kinetic parameters have been determined. The crystal structure of some nitroreductases have also been solved. However, the physiological role(s) of these enzymes remains unclear. Nitroreductase genes are widely spread within bacterial genomes, but are also found in archaea and some eukaryotic species. Although studies on regulation of nitroreductase gene expression are scarce, it seems that nitroreductase genes may be controlled by the MarRA and SoxRS regulatory systems that are involved in responses to several antibiotics and environmental chemical hazards and to specific oxidative stress conditions. This review covers the microbial distribution, types, biochemical properties, structure and regulation of the bacterial nitroreductases. The possible physiological functions and the biotechnological applications of these enzymes are also discussed.
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Affiliation(s)
- María Dolores Roldán
- Departamento de Bioquímica y Biología Molecular, Campus de Rabanales, Universidad de Córdoba, Córdoba, Spain.
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Liu G, Zhou J, Lv H, Xiang X, Wang J, Zhou M, Qv Y. Azoreductase from Rhodobacter sphaeroides AS1.1737 is a flavodoxin that also functions as nitroreductase and flavin mononucleotide reductase. Appl Microbiol Biotechnol 2007; 76:1271-9. [PMID: 17846764 DOI: 10.1007/s00253-007-1087-5] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 06/04/2007] [Accepted: 06/10/2007] [Indexed: 11/30/2022]
Abstract
Previously reported azoreductase (AZR) from Rhodobacter sphaeroides AS1.1737 was shown to be a flavodoxin possessing nitroreductase and flavin mononucleotide (FMN) reductase activities. The structure model of AZR constructed with SWISS-MODEL displayed a flavodoxin-like fold with a three-layer alpha/beta/alpha structure. With nitrofurazone as substrate, the optimal pH value and temperature were 7.0 and 50 degrees C, respectively. AZR could reduce a number of nitroaromatic compounds including 2,4-dinitrotoluene, 2,6-dinitrotoluene, 3,5-dinitroaniline, and 2,4,6-trinitrotoluene (TNT). TNT resulted to be the most efficient nitro substrate and was reduced to hydroxylamino-dinitrotoluene. Both NADH and NADPH could serve as electron donors of AZR, where the latter was preferred. Externally added FMN was also reduced by AZR via ping-pong mechanism and was a competitive inhibitor of NADPH, methyl red, and nitrofurazone. AZR with broad substrate specificity is a member of a new nitro/FMN reductase family demonstrating potential application in bioremediation.
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Affiliation(s)
- Guangfei Liu
- School of Environmental and Biological Science and Technology, Dalian University of Technology, 116024 Dalian, People's Republic of China.
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González-Pérez MM, van Dillewijn P, Wittich RM, Ramos JL. Escherichia coli has multiple enzymes that attack TNT and release nitrogen for growth. Environ Microbiol 2007; 9:1535-40. [PMID: 17504490 DOI: 10.1111/j.1462-2920.2007.01272.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There has been a growing interest in the degradation of 2,4,6-trinitrotoluene (TNT) over the last decade, ever since its removal from polluted sites was declared an international environmental priority. Certain aerobic and anaerobic microorganisms are capable of using TNT as an N source, although very few studies have proven the mineralization of this compound. An unexpected observation in our laboratory led us to discover that certain Escherichia coli bench laboratory strains have multiple enzymes that attack TNT. One of the NemA products is responsible for the release of nitrite from the nitroaromatic ring: among the metabolites observed in vitro include Meisenheimer dihydride complexes of TNT from which 2-hydroxylamino-6-nitrotoluene is slowly formed during their rearomatization under concomitant release of nitrite. Furthermore, NemA, together with NfsA and NfsB reduce the nitro groups on the aromatic ring to the corresponding hydroxylamino derivatives, which probably results in the release of ammonium ions which can, in turn be used as a nitrogen source by E. coli for growth.
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Affiliation(s)
- M Mar González-Pérez
- Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Apdo. Correos 419, E-18008 Granada, Spain
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Smets BF, Yin H, Esteve-Nuñez A. TNT biotransformation: when chemistry confronts mineralization. Appl Microbiol Biotechnol 2007; 76:267-77. [PMID: 17534614 DOI: 10.1007/s00253-007-1008-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 04/19/2007] [Accepted: 04/19/2007] [Indexed: 10/23/2022]
Abstract
Our understanding of the genetics and biochemistry of microbial 2,4,6-trinitrotoluene (TNT) biotransformation has advanced significantly during the past 10 years, and biotreatment technologies have developed. In this review, we summarize this new knowledge. A number of enzyme classes involved in TNT biotransformation include the type I nitroreductases, the old yellow enzyme family, a respiration-associated nitroreductase, and possibly ring hydroxylating dioxygenases. Several strains harbor dual pathways: nitroreduction (reduction of the nitro group in TNT to a hydroxylamino and/or amino group) and denitration (reduction of the aromatic ring of TNT to Meisenheimer complexes with nitrite release). TNT can serve as a nitrogen source for some strains, and the postulated mechanism involves ammonia release from hydroxylamino intermediates. Field biotreatment technologies indicate that both stimulation of microbial nitroreduction and phytoremediation result in significant and permanent immobilization of TNT via its metabolites. While the possibility for TNT mineralization was rekindled with the discovery of TNT denitration and oxygenolytic and respiration-associated pathways, further characterization of responsible enzymes and their reaction mechanisms are required.
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Affiliation(s)
- Barth F Smets
- Institute of Environment and Resources, Technical University of Denmark, Bygningstorvet, Bldg 115, 2800 Kgs. Lyngby, Denmark.
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Stenuit B, Eyers L, Rozenberg R, Habib-Jiwan JL, Agathos SN. Aerobic growth of Escherichia coli with 2,4,6-trinitrotoluene (TNT) as the sole nitrogen source and evidence of TNT denitration by whole cells and cell-free extracts. Appl Environ Microbiol 2006; 72:7945-8. [PMID: 17012591 PMCID: PMC1694216 DOI: 10.1128/aem.01052-06] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2006] [Accepted: 09/25/2006] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli grew aerobically with 2,4,6-trinitrotoluene (TNT) as sole nitrogen source and caused TNT's partial denitration. This reaction was enhanced in nongrowing cell suspensions with 0.516 mol nitrite released per mol TNT. Cell extracts denitrated TNT in the presence of NAD(P)H. Isomers of amino-dimethyl-tetranitrobiphenyl were detected and confirmed with U-15N-labeled TNT.
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Affiliation(s)
- Ben Stenuit
- Unit of Bioengineering, Department of Applied Chemistry and Bioindustries, Catholic University of Lovain, Place Croix du Sud 2/19, 1348 Louvain-la-Neuve, Belgium
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