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Gupta S, Goel SS, Ramanathan G, Ronen Z. Biotransformation of 2,4,6-trinitrotoluene by Diaphorobacter sp. strain DS2. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:120749-120762. [PMID: 37943434 DOI: 10.1007/s11356-023-30651-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 10/20/2023] [Indexed: 11/10/2023]
Abstract
Diaphorobacter strain DS2 degrades 3-nitrotoluene and 2-nitrotoluene via ring oxidation with 3-nitrotoluene dioxygenase (3NTDO). In the current study, we hypothesized that 3NTDO might also be involved in the degradation of 2,4,6-trinitrotoluene (TNT), a major nitroaromatic explosive contaminant in soil and groundwater. Strain DS2 transforms TNT as a sole carbon and nitrogen source when grown on it. Ammonium chloride and succinate in the medium accelerated the TNT degradation rate. A resting cell experiment suggested that TNT does not compete with 3NT degradation (no negative impact of TNT on the reaction velocity for 3NT). Enzyme assay with 3NTDO did not exhibit TNT transformation activity. The above results confirmed that 3NTDO of DS2 is not responsible for TNT degradation. In the resting cell experiment, within 10 h, 4ADNT completely degraded. The degradation of 2ADNT was 97% at the same time. We hypothesized that 3NTDO involve in this reaction. Based on the DS2 genome, we proposed that the N-ethylmaleimide reductases (nemA) were involved in the initial reduction of the nitro group and aromatic ring of TNT. Our findings suggest that strain DS2 could be helpful for the removal of TNT from contaminated sites with or without any additional carbon and nitrogen source and with minimal accumulation of undesirable intermediates.
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Affiliation(s)
- Swati Gupta
- Department of Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker Campus 8490000, Be'er Sheva, Israel
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Shikhar S Goel
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Gurunath Ramanathan
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Zeev Ronen
- Department of Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker Campus 8490000, Be'er Sheva, Israel.
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Yin ML, Zhao SP, Lai JL, Yang X, Dong B, Zhu YB, Zhang Y. Oxygen-insensitive nitroreductase bacteria-mediated degradation of TNT and proteomic analysis. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:116227-116238. [PMID: 37907824 DOI: 10.1007/s11356-023-30568-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 10/16/2023] [Indexed: 11/02/2023]
Abstract
2,4,6-trinitrotoluene (TNT) is a nitroaromatic compound that causes soil and groundwater pollution during manufacture, transportation, and use, posing significant environmental and safety hazards. In this study, a TNT-degrading strain, Bacillus cereus strain T4, was screened and isolated from TNT-contaminated soil to explore its degradation characteristics and proteomic response to TNT. The results showed that after inoculation with the bacteria for 4 h, the TNT degradation rate reached 100% and was transformed into 2-amino-4,6-dinitrotoluene (2-ADNT), 4-amino-2,6-dinitrotoluene (4-ADNT), 2,4-diamino-6-nitrotoluene (2,4-DANT), and 2,6-diamino-4-nitrotoluene (2,6-DANT), accompanied by the accumulation of nitrite and ammonium ions. Through proteomic sequencing, we identified 999 differentially expressed proteins (482 upregulated, 517 downregulated), mainly enriched in the pentose phosphate, glycolysis/gluconeogenesis, and amino acid metabolism pathways. In addition, the significant upregulation of nitroreductase and N-ethylmaleimide reductase was closely related to TNT denitration and confirmed that the strain T4 converted TNT into intermediate metabolites such as 2-ADNT and 4-ADNT. Therefore, Bacillus cereus strain T4 has the potential to degrade TNT and has a high tolerance to intermediate products, which may effectively degrade nitroaromatic pollutants such as TNT in situ remediation in combination with other bacterial communities.
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Affiliation(s)
- Mao-Ling Yin
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
| | - San-Ping Zhao
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China.
| | - Jin-Long Lai
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Xu Yang
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Bin Dong
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Yong-Bing Zhu
- State Key Laboratory of NBC Protection for Civilian, Beijing, 102205, China
| | - Yu Zhang
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, 621010, China
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Gupta S, Goel SS, Siebner H, Ronen Z, Ramanathan G. Transformation of 2, 4, 6-trinitrotoluene by Stenotrophomonas strain SG1 under aerobic and anaerobic conditions. CHEMOSPHERE 2023; 311:137085. [PMID: 36328316 DOI: 10.1016/j.chemosphere.2022.137085] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/28/2022] [Accepted: 10/29/2022] [Indexed: 06/16/2023]
Abstract
TNT, or 2,4,6-trinitrotoluene, is a common explosive that can contaminate soil and groundwater in production sites, military training areas, and disposal locations. The compound is highly toxic; therefore, there is an urgent need to rehabilitate the impacted environments. Harnessing the microbial ability to biodegrade TNT into environmentally harmless compound(s) is one approach to remediating contaminated sites. In our study, we report on the genomic and metabolic ability of Stenotrophomonas strain SG1 to degrade TNT under aerobic and anaerobic conditions. The bacterial strain SG1 was first isolated as a contaminant from a culture of Diaphorobacter sp. strain DS2 over minimal media supplemented with TNT. The draft genome assembly of strain SG1 is ∼4.7 Mb and is distributed among 358 contigs. The homology search against the custom database of enzymes responsible for TNT biodegradation revealed the presence of three N-ethylmaleimide reductases (NemA) with a defined KEGG ortholog and KEGG pathway of TNT degradation. The presence of respiratory nitrate reductases has also been mapped, which supports denitrification under anaerobic conditions. Experimentally, the TNT transformation rate accelerated when carbon sources, such as sodium acetate, sodium citrate, sodium succinate, sucrose, and glucose (final concentration of 5 mM), were added. Citrate promoted the highest growth and TNT transformation ratio (88.35%) in 120 h. With the addition of 5 mM ammonium chloride, TNT completely disappeared in the citrate and sucrose-containing treatments in 120 h. However, higher biomass was obtained in the sucrose and glucose-containing treatments in 120 h. During incubation, the formation of amino dinitrotoluene isomers, dinitrotoluene isomers, trinitrobenzene, azoxy isomers, diaryl hydroxylamines, and corresponding secondary amines was confirmed by GC/MS and UPLC/MS. 2-Amino-4-nitrotoluene, 4-amino-2-nitrotoluene, and 2-amino-6-nitrotoluene were also identified in the culture supernatant by GC/MS. Under anaerobic conditions, TNT completely disappeared in the citrate and citrate plus nitrate treatments. Since the strain shows the ability to remove TNT, this research should be useful in basic research and practical applications for removing TNT from wastewater.
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Affiliation(s)
- Swati Gupta
- Department of Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker Campus, 8490000, Israel; Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Shikhar S Goel
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India
| | - Hagar Siebner
- Department of Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker Campus, 8490000, Israel
| | - Zeev Ronen
- Department of Environmental Hydrology and Microbiology, The Zuckerberg Institute for Water Research, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sde Boker Campus, 8490000, Israel.
| | - Gurunath Ramanathan
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
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Aamir Khan M, Sharma A, Yadav S, Celin SM, Sharma S. A sketch of microbiological remediation of explosives-contaminated soil focused on state of art and the impact of technological advancement on hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) degradation. CHEMOSPHERE 2022; 294:133641. [PMID: 35077733 DOI: 10.1016/j.chemosphere.2022.133641] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/02/2022] [Accepted: 01/13/2022] [Indexed: 06/14/2023]
Abstract
When high-energy explosives such as hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 2,4,6-trinitrotoluene (TNT) are discharged into the surrounding soil and water during production, testing, open dumping, military, or civil activities, they leave a toxic footprint. The US Environmental Protection Agency has labeled RDX as a potential human carcinogen that must be degraded from contaminated sites quickly. Bioremediation of RDX is an exciting prospect that has received much attention in recent years. However, a lack of understanding of RDX biodegradation and the limitations of current approaches have hampered the widespread use of biodegradation-based strategies for RDX remediation at contamination sites. Consequently, new bioremediation technologies are required to enhance performance. In this review, we explore the requirements for in-silico analysis for producing biological models of microbial remediation of RDX in soil. On the other hand, potential gene editing methods for getting the host with target gene sequences responsible for the breakdown of RDX are also reported. Microbial formulations and biosensors for detection and bioremediation are also briefly described. The biodegradation of RDX offers an alternative remediation method that is both cost-effective and ecologically acceptable. It has the potential to be used in conjunction with other cutting-edge technologies to further increase the efficiency of RDX degradation.
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Affiliation(s)
- Mohd Aamir Khan
- Centre for Rural Development & Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - Abhishek Sharma
- Amity Food and Agriculture Foundation, Amity University Uttar Pradesh, Noida, 201313, India.
| | - Sonal Yadav
- Centre for Rural Development & Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
| | - S Mary Celin
- Centre for Fire, Explosives and Environment Safety, Defence Research & Development Organization, Brig. Mazumdar Road, Delhi, 110 054, India
| | - Satyawati Sharma
- Centre for Rural Development & Technology, Indian Institute of Technology Delhi, Hauz Khas, New Delhi, 110016, India
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Lamba J, Anand S, Dutta J, Chatterjee S, Nagar S, Celin SM, Rai PK. Study on aerobic degradation of 2,4,6-trinitrotoluene (TNT) using Pseudarthrobacter chlorophenolicus collected from the contaminated site. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:80. [PMID: 33486600 DOI: 10.1007/s10661-021-08869-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 01/11/2021] [Indexed: 06/12/2023]
Abstract
2,4,6-trinitrotoluene or TNT, a commonly used explosive, can pollute soil and groundwater. Conventional remediation practices for the TNT-contaminated sites are neither eco-friendly nor cost-effective. However, exploring bacteria to biodegrade TNT into environment-friendly compound(s) is an interesting area to explore. In this study, an indigenous bacterium, Pseudarthrobacter chlorophenolicus, strain S5-TSA-26, isolated from explosive contaminated soil, was investigated for potential aerobic degradation of TNT for the first time. The isolated strain of P. chlorophenolicus was incubated in a minimal salt medium (MSM) containing 120 mg/L TNT for 25 days at specified conditions. TNT degradation pattern by the bacterium was monitored at regular interval using UV-Vis spectrophotometry, high-performance liquid chromatography, and liquid chromatography mass spectrophotometric, by estimating nitrate, nitrite, and ammonium ion concentration and other metabolites such as 2,4-dinitrotoluene (DNT), 2-amino-4,6-dinitrotoluene (2-ADNT), and 2,4-diamino-6-nitrotoluene (2-DANT). It was observed that, in the presence of TNT, there was no reduction in growth of the bacterium although it multiplied well in the presence of TNT along with no considerable morphological changes. Furthermore, it was found that TNT degraded completely within 15 days of incubation. Thus, from this study, it may be concluded that the bacterium has the potential for degrading TNT completely with the production of non-toxic by-products and might be an important bacterium for treating TNT (i.e., a nitro-aromatic compound)-contaminated sites.
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Affiliation(s)
- Jyoti Lamba
- Department of Environment Studies, Panjab University, Chandigarh, 160 014, India
- Centre for Fire, Explosive and Environment Safety (CFEES), Defence Research and Development Organisation (DRDO), Timarpur, Delhi, 110054, India
| | - Shalini Anand
- Centre for Fire, Explosive and Environment Safety (CFEES), Defence Research and Development Organisation (DRDO), Timarpur, Delhi, 110054, India.
| | - Jayanti Dutta
- Human Resource Development Centre, Panjab University, Chandigarh, 160 014, India
| | - Soumya Chatterjee
- Defence Research Laboratory, Defence Research and Development Organisation, Tezpur, Assam, 784 001, India
| | - Shilpi Nagar
- Centre for Fire, Explosive and Environment Safety (CFEES), Defence Research and Development Organisation (DRDO), Timarpur, Delhi, 110054, India
- Department of Environmental Studies, University of Delhi, Delhi, 110 007, India
| | - S Mary Celin
- Centre for Fire, Explosive and Environment Safety (CFEES), Defence Research and Development Organisation (DRDO), Timarpur, Delhi, 110054, India
| | - Pramod Kumar Rai
- Centre for Fire, Explosive and Environment Safety (CFEES), Defence Research and Development Organisation (DRDO), Timarpur, Delhi, 110054, India
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