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Mohammadi E, Baldwin SA. Developing a versatile tool for studying kinetics of Selenate-Se removal from aqueous solution using a chemostat bioreactor. Heliyon 2024; 10:e24914. [PMID: 38317929 PMCID: PMC10839987 DOI: 10.1016/j.heliyon.2024.e24914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 01/09/2024] [Accepted: 01/17/2024] [Indexed: 02/07/2024] Open
Abstract
Understanding the impact of various parameters on the kinetics of dissolved selenium (Se) removal in bioreactors can be a challenging task, primarily due to the mass transfer limitations inherent in bioreactors employing attached growth configurations. This study successfully established a proof-of-concept for the efficient removal of Se from aqueous solutions using a chemostat bioreactor that relies solely on suspended growth. The research investigated the effect of selenate-Se feed concentrations under two distinct Se concentration conditions. One experiment was conducted at a considerably elevated concentration of 25 mg/L to impose stress on the system and evaluate its response. Another experiment replicated an environmentally relevant concentration of 1 mg/L, mirroring the typical Se concentrations in mine water. The bioreactor, featuring a working volume of 0.35 L, was operated as an anaerobic, fully mixed chemostat with hydraulic retention times (HRTs) ranging from 5 to 0.25 days. The outcomes revealed the chemostat's capacity to remove up to 25 mg/L of dissolved Se from water for all HRTs exceeding 1 day, under otherwise optimal conditions encompassing temperature, pH, and salinity. The research's significance lies in the development of a versatile tool designed to examine Se removal kinetics within a system devoid of mass transfer limitations. Furthermore, this study verified the ability of the bacterial consortium, obtained from a mine-influenced environment and enriched in the laboratory, to grow and sustain Se removal activities within a chemostat operating with HRTs as short as 1 day.
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Affiliation(s)
- Elnaz Mohammadi
- Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Susan A. Baldwin
- Chemical and Biological Engineering, University of British Columbia, 2360 East Mall, Vancouver, British Columbia, V6T 1Z3, Canada
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2
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Lashani E, Moghimi H, J Turner R, Amoozegar MA. Selenite bioreduction by a consortium of halophilic/halotolerant bacteria and/or yeasts in saline media. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023:121948. [PMID: 37270053 DOI: 10.1016/j.envpol.2023.121948] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 05/18/2023] [Accepted: 05/31/2023] [Indexed: 06/05/2023]
Abstract
Selenium oxyanions are released into environments by natural and anthropogenic activities and are present in agricultural and glass manufacturing wastewater in several locations worldwide. Excessive amounts of this metalloid have adverse effects on the health of living organisms. Halophilic and halotolerant microorganisms were selected for selenium oxyanions remediation due to presence of significant amount of salt in selenium-containing wastewater. Effects of aeration, carbon sources, competitive electron acceptors, and reductase inhibitors were investigated on SeO32- bio-removal. Additionally, NO3--containing wastewater were exploited to investigate SeO32- remediation in synthetic agricultural effluents. The results showed that the SeO32- removal extent is maximum in aerobic conditions with succinate as a carbon source. SO42- and PO43- do not significantly interfere with SeO32- reduction, while WO42- and TeO32- decrease the SeO32- removal percentage (up to 35 and 37%, respectively). Furthermore, NO3- had an adverse effect on SeO32- biotransformation by our consortia. All consortia reduced SeO32- in synthetic agricultural wastewaters with a 45-53% removal within 120 h. This study suggests that consortia of halophilic/halotolerant bacteria and yeasts could be applied to treat SeO32--contaminated drainage water. In addition, sulphates, and phosphates do not interfere with selenite bioreduction by these consortia, which makes them suitable candidates for the bioremediation of selenium-containing wastewater.
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Affiliation(s)
- Elham Lashani
- Extremophiles Laboratory, Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran
| | - Hamid Moghimi
- Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran.
| | - Raymond J Turner
- Microbial Biochemistry Laboratory, Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB, T2N 1N4, Canada
| | - Mohammad Ali Amoozegar
- Extremophiles Laboratory, Department of Microbiology, School of Biology, College of Science, University of Tehran, Tehran, Iran
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3
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Povedano-Priego C, Jroundi F, Solari PL, Guerra-Tschuschke I, Abad-Ortega MDM, Link A, Vilchez-Vargas R, Merroun ML. Unlocking the bentonite microbial diversity and its implications in selenium bioreduction and biotransformation: Advances in deep geological repositories. JOURNAL OF HAZARDOUS MATERIALS 2023; 445:130557. [PMID: 36502723 DOI: 10.1016/j.jhazmat.2022.130557] [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: 09/12/2022] [Revised: 11/28/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Selenium, 79Se, is one of the most critical radionuclides in radioactive waste disposed in future deep geological repositories (DGRs). Here, we investigate the impact of bentonite microbial communities on the allotropic transformation of Se(IV) bioreduction products under DGR relevant conditions. In addition, Se amendment-dependent shifts in the bentonite microbial populations are assessed. Microcosms of water-saturated bentonites were spiked with a bacterial consortium, treated with selenite and incubated anaerobically for six months. A combination of X-Ray Absorption Spectroscopy, Electron Microscopy, and Raman Spectroscopy was used to track the allotropic changes of the Se bioreduction products. Interestingly, the color of bentonite shifted from orange to black in the selenite-treated microcosms. In the orange layers, amorphous or monoclinic Se(0) were identified, whilst black precipitates consisted of stable trigonal Se(0) form. Illumina DNA sequencing indicated the distribution of strains with Se(IV) reducing and Se(0) allotropic biotransformation potential, like Pseudomonas, Stenotrophomonas, Desulfosporosinus, and unclassified-Desulfuromonadaceae. The archaea Methanosarcina decreased its abundance in the presence of Se(IV), probably caused by this oxyanion toxicity. These findings provide an understanding of the bentonite microbial strategies involved in the immobilization of Se(IV) by reduction processes, and prove their implication in the allotropic biotransformation from amorphous to trigonal Se(0) under DGR relevant conditions.
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Affiliation(s)
| | - Fadwa Jroundi
- Department of Microbiology, Faculty of Sciences, University of Granada, Granada, Spain.
| | - Pier L Solari
- MARS Beamline, Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, Gif-sur-Yvette Cedex, France.
| | | | | | - Alexander Link
- Department of Gastroenterology, Hepatology and Infectious Diseases, University of Magdeburg, Magdeburg, Germany.
| | - Ramiro Vilchez-Vargas
- Department of Gastroenterology, Hepatology and Infectious Diseases, University of Magdeburg, Magdeburg, Germany.
| | - Mohamed L Merroun
- Department of Microbiology, Faculty of Sciences, University of Granada, Granada, Spain.
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Liu H, Xiao C, Qiu T, Deng J, Cheng H, Cong X, Cheng S, Rao S, Zhang Y. Selenium Regulates Antioxidant, Photosynthesis, and Cell Permeability in Plants under Various Abiotic Stresses: A Review. PLANTS (BASEL, SWITZERLAND) 2022; 12:44. [PMID: 36616173 PMCID: PMC9824017 DOI: 10.3390/plants12010044] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/06/2022] [Accepted: 12/19/2022] [Indexed: 06/17/2023]
Abstract
Plant growth is affected by various abiotic stresses, including water, temperature, light, salt, and heavy metals. Selenium (Se) is not an essential nutrient for plants but plays important roles in alleviating the abiotic stresses suffered by plants. This article summarizes the Se uptake and metabolic processes in plants and the functions of Se in response to water, temperature, light, salt, and heavy metal stresses in plants. Se promotes the uptake of beneficial substances, maintains the stability of plasma membranes, and enhances the activity of various antioxidant enzymes, thus alleviating adverse effects in plants under abiotic stresses. Future research directions on the relationship between Se and abiotic stresses in plants are proposed. This article will further deepen our understanding of the relationship between Se and plants.
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Affiliation(s)
- Haodong Liu
- School of Modern Industry for Selenium Science and Engineering, National R&D Center for Se-Rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan 430023, China
| | - Chunmei Xiao
- School of Modern Industry for Selenium Science and Engineering, National R&D Center for Se-Rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan 430023, China
| | - Tianci Qiu
- School of Modern Industry for Selenium Science and Engineering, National R&D Center for Se-Rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan 430023, China
| | - Jie Deng
- School of Modern Industry for Selenium Science and Engineering, National R&D Center for Se-Rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan 430023, China
| | - Hua Cheng
- School of Modern Industry for Selenium Science and Engineering, National R&D Center for Se-Rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan 430023, China
| | - Xin Cong
- School of Modern Industry for Selenium Science and Engineering, National R&D Center for Se-Rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan 430023, China
- Enshi Se-Run Material Engineering Technology Co., Ltd., Enshi 445000, China
| | - Shuiyuan Cheng
- School of Modern Industry for Selenium Science and Engineering, National R&D Center for Se-Rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan 430023, China
| | - Shen Rao
- School of Modern Industry for Selenium Science and Engineering, National R&D Center for Se-Rich Agricultural Products Processing Technology, Wuhan Polytechnic University, Wuhan 430023, China
| | - Yue Zhang
- Enshi Se-Run Material Engineering Technology Co., Ltd., Enshi 445000, China
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5
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Enhancing the Activity of Carboxymethyl Cellulase Enzyme Using Highly Stable Selenium Nanoparticles Biosynthesized by Bacillus paralicheniformis Y4. Molecules 2022; 27:molecules27144585. [PMID: 35889450 PMCID: PMC9324468 DOI: 10.3390/molecules27144585] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/03/2022] [Accepted: 07/13/2022] [Indexed: 02/01/2023] Open
Abstract
The inorganic selenium is absorbed and utilized inefficiently, and the range between toxicity and demand is narrow, so the application is strictly limited. Selenium nanoparticles have higher bioactivity and biosafety properties, including increased antioxidant and anticancer properties. Thus, producing and applying eco-friendly, non-toxic selenium nanoparticles in feed additives is crucial. Bacillus paralicheniformis Y4 was investigated for its potential ability to produce selenium nanoparticles and the activity of carboxymethyl cellulases. The selenium nanoparticles were characterized using zeta potential analyses, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). Additionally, evaluations of the anti-α-glucosidase activity and the antioxidant activity of the selenium nanoparticles and the ethyl acetate extracts of Y4 were conducted. B. paralicheniformis Y4 exhibited high selenite tolerance of 400 mM and the selenium nanoparticles had an average particle size of 80 nm with a zeta potential value of −35.8 mV at a pH of 7.0, suggesting that the particles are relatively stable against aggregation. After 72 h of incubation with 5 mM selenite, B. paralicheniformis Y4 was able to reduce it by 76.4%, yielding red spherical bio-derived selenium nanoparticles and increasing the carboxymethyl cellulase activity by 1.49 times to 8.96 U/mL. For the first time, this study reports that the carboxymethyl cellulase activity of Bacillus paralicheniforis was greatly enhanced by selenite. The results also indicated that B. paralicheniformis Y4 could be capable of ecologically removing selenite from contaminated sites and has great potential for producing selenium nanoparticles as feed additives to enhance the added value of agricultural products.
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6
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Abejón R. A Bibliometric Analysis of Research on Selenium in Drinking Water during the 1990-2021 Period: Treatment Options for Selenium Removal. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:5834. [PMID: 35627373 PMCID: PMC9140891 DOI: 10.3390/ijerph19105834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/01/2022] [Accepted: 05/04/2022] [Indexed: 02/01/2023]
Abstract
A bibliometric analysis based on the Scopus database was carried out to summarize the global research related to selenium in drinking water from 1990 to 2021 and identify the quantitative characteristics of the research in this period. The results from the analysis revealed that the number of accumulated publications followed a quadratic growth, which confirmed the relevance this research topic is gaining during the last years. High research efforts have been invested to define safe selenium content in drinking water, since the insufficient or excessive intake of selenium and the corresponding effects on human health are only separated by a narrow margin. Some important research features of the four main technologies most frequently used to remove selenium from drinking water (coagulation, flocculation and precipitation followed by filtration; adsorption and ion exchange; membrane-based processes and biological treatments) were compiled in this work. Although the search of technological options to remove selenium from drinking water is less intensive than the search of solutions to reduce and eliminate the presence of other pollutants, adsorption was the alternative that has received the most attention according to the research trends during the studied period, followed by membrane technologies, while biological methods require further research efforts to promote their implementation.
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Affiliation(s)
- Ricardo Abejón
- Departamento de Ingeniería Química, Universidad de Santiago de Chile (USACH), Av. Libertador Bernardo O'Higgins 3363, Estación Central, Santiago 9170019, Chile
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7
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Huang J, Jiang D, Wang M, Huang X. Highly Selenite-Tolerant Strain Proteus mirabilis QZB-2 Rapidly Reduces Selenite to Selenium Nanoparticles in the Cell Membrane. Front Microbiol 2022; 13:862130. [PMID: 35479612 PMCID: PMC9037631 DOI: 10.3389/fmicb.2022.862130] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/14/2022] [Indexed: 12/02/2022] Open
Abstract
The application of biosynthesized nano-selenium fertilizers to crops can improve their nutrient levels by increasing their selenium content. However, microorganisms with a high selenite tolerance and rapid reduction rate accompanied with the production of selenium nanoparticles (SeNPs) at the same time have seldom been reported. In this study, a bacterial strain showing high selenite resistance (up to 300 mM) was isolated from a lateritic red soil and identified as Proteus mirabilis QZB-2. This strain reduced nearly 100% of 1.0 and 2.0 mM selenite within 12 and 18 h, respectively, to produce SeNPs. QZB-2 isolate reduced SeO32– to Se0 in the cell membrane with NADPH or NADH as electron donors. Se0 was then released outside of the cell, where it formed spherical SeNPs with an average hydrodynamic diameter of 152.0 ± 10.2 nm. P. mirabilis QZB-2 could be used for SeNPs synthesis owing to its simultaneously high SeO32– tolerance and rapid reduction rate.
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Affiliation(s)
- JinLan Huang
- Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Guangxi University, Nanning, China
| | - DaiHua Jiang
- Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Guangxi University, Nanning, China
| | - MingShi Wang
- Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Guangxi University, Nanning, China
| | - XueJiao Huang
- Guangxi Colleges and Universities Key Laboratory of Crop Cultivation and Tillage, Guangxi University, Nanning, China
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8
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Zhou C, Wang ZJ, Huang JC, Zheng L, Gan X, Zhang M, He S, Zhou W. Se transformation and removal by a cattail litter treatment system inoculated with sulfur-based denitrification sludge: Role of the microbial community composition under various temperature and aeration conditions. JOURNAL OF HAZARDOUS MATERIALS 2021; 420:126617. [PMID: 34271446 DOI: 10.1016/j.jhazmat.2021.126617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 06/17/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
With a narrow margin between deficiency and toxicity, rising levels of selenium (Se) are threatening aquatic ecosystems. To investigate the role of microorganisms in Se bioremediation, a cattail litter system inoculated with the sulfur-based denitrification sludge was conducted. The results show the litter, as a carrier and nutrient source for bacteria, efficiently removed Se by ~ 97.0% during a 12-d treatment with water circulating. As the major removal pathways, immobilization rates of selenite were ~ 2.9-fold higher than selenate, and the volatilization, contributing to ~ 87.7% of the total Se removal, was significantly correlated with temperature (positively) and oxidation-reduction potential (ORP; negatively). Using X-ray absorption spectroscopy to speciate litter-borne Se, more Se0 formed without aeration due to abundant Se-reducing bacteria, among which Azospira and Azospirillum were highly related to the removal of both Se oxyanions, while Desulfovibrio, Azoarcus, Sulfurospirillum, Thauera, Geobacter, Clostridium, and Pediococcus were the major contributors to selenate removal. Overall, our study suggests microbial Se metabolism in the litter system was significantly affected by temperature and ORP, which could be manipulated to enhance Se removal efficiency and the transformation of selenate/selenite into low toxic Se0 and volatile Se, reducing risks posed by the residual Se in the system.
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Affiliation(s)
- Chuanqi Zhou
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zi-Jing Wang
- Department of Environmental Engineering, National Cheng Kung University, Tainan City 701, Taiwan, ROC
| | - Jung-Chen Huang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Department of Environmental Engineering, National Cheng Kung University, Tainan City 701, Taiwan, ROC.
| | - Lixin Zheng
- Department of Environmental Science and Engineering, Fudan University, Shanghai 200438, China
| | - Xinyu Gan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Manping Zhang
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shengbing He
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Weili Zhou
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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9
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Li L, Zhang B, He C, Zhang H. Hydrodynamics- and hydrochemistry-affected microbial selenate reduction in aquifer: Performance and mechanisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 768:145331. [PMID: 33736316 DOI: 10.1016/j.scitotenv.2021.145331] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/15/2021] [Accepted: 01/17/2021] [Indexed: 06/12/2023]
Abstract
Selenate [Se(VI)] with higher content in groundwater will be harmful for human beings. Hence, effective treatment for Se(VI) in aquifer should be conducted reasonably. Microbial reduction of Se(VI) to elemental selenium with weak movability and toxicity has attracted significant attention due to its high efficiency and no secondary contamination. However, hydrodynamic and hydrochemical influences with corresponding mechanisms during Se(VI) bioreduction are still not clear. In this study, influences of flow rate, initial Se(VI) and organic concentrations, coexisting nitrate were evaluated. Se(VI) removal efficiency and capacity reached 96.42 ± 6.82% and 41.28 ± 3.41 (g/m3·d) with flow rate of 0.56 mL/min, initial Se(VI) and chemical organic demand concentrations of 10 mg/L and 400 mg/L. Dechloromonas and Pseudomonas were presumably contributed to Se(VI) reduction, with upregulated serA and tatC genes. Solid Se0 was identified as the final product from Se(VI) reduction. These results will be beneficial for the further comprehending of Se(VI) remediation in aquifer.
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Affiliation(s)
- Liuliu Li
- School of Water Resources and Environment, Key Laboratory of Groundwater Circulation and Environmental Evolution (China University of Geosciences Beijing), Ministry of Education, Beijing 100083, China
| | - Baogang Zhang
- School of Water Resources and Environment, Key Laboratory of Groundwater Circulation and Environmental Evolution (China University of Geosciences Beijing), Ministry of Education, Beijing 100083, China.
| | - Chao He
- School of Water Resources and Environment, Key Laboratory of Groundwater Circulation and Environmental Evolution (China University of Geosciences Beijing), Ministry of Education, Beijing 100083, China
| | - Han Zhang
- School of Water Resources and Environment, Key Laboratory of Groundwater Circulation and Environmental Evolution (China University of Geosciences Beijing), Ministry of Education, Beijing 100083, China
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10
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Wadgaonkar SL, Nancharaiah YV, Jacob C, Esposito G, Lens PNL. Microbial transformation of Se oxyanions in cultures of Delftia lacustris grown under aerobic conditions. J Microbiol 2019; 57:362-371. [PMID: 30900147 DOI: 10.1007/s12275-019-8427-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/20/2018] [Accepted: 11/26/2018] [Indexed: 12/29/2022]
Abstract
Delftia lacustris is reported for the first time as a selenate and selenite reducing bacterium, capable of tolerating and growing in the presence of ≥ 100 mM selenate and 25 mM selenite. The selenate reduction profiles of D. lacustris were investigated by varying selenate concentration, inoculum size, concentration and source of organic electron donor in minimal salt medium. Interestingly, the bacterium was able to reduce both selenate and selenite under aerobic conditions. Although considerable removal of selenate was observed at all concentrations investigated, D. lacustris was able to completely reduce 0.1 mM selenate within 96 h using lactate as the carbon source. Around 62.2% unaccounted selenium (unidentified organo-selenium compounds), 10.9% elemental selenium and 26.9% selenite were determined in the medium after complete reduction of selenate. Studies of the enzymatic activity of the cell fractions show that the selenite/selenate reducing enzymes were intracellular and independent of NADPH availability. D. lacustris shows an unique metabolism of selenium oxyanions to form elemental selenium and possibly also selenium ester compounds, thus a potential candidate for the remediation of selenium-contaminated wastewaters in aerobic environments. This novel finding will advance the field of bioremediation of selenium-contaminated sites and selenium bio-recovery and the production of potentially beneficial organic and inorganic reactive selenium species.
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Affiliation(s)
| | - Yarlagadda V Nancharaiah
- Biofouling and Biofilm Processes Section of Water and Steam Chemistry Division, Bhabha Atomic Research Centre, 603 102, Kalpakkam, Tamil Nadu, India
- Homi Bhabha National Institute, Anushakti Nagar Complex, Mumbai, 400 094, India
| | - Claus Jacob
- Division of Bioorganic Chemistry, School of Pharmacy, Saarland University, Campus B2, Saarland, Germany
| | - Giovanni Esposito
- Department of Civil, Architectural and Environmental Engineering, University of Napoli "Federico II", 80125, Napoli, Italy
| | - Piet N L Lens
- UNESCO IHE Institute for water Education, Delft, DA 2601, The Netherlands
- National University of Ireland Galway, Galway, H91 TK33, Ireland
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11
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Nitrate Reductases Are Relocalized to the Nucleus by AtSIZ1 and Their Levels Are Negatively Regulated by COP1 and Ammonium. Int J Mol Sci 2018; 19:ijms19041202. [PMID: 29662028 PMCID: PMC5979280 DOI: 10.3390/ijms19041202] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/11/2018] [Accepted: 04/11/2018] [Indexed: 01/18/2023] Open
Abstract
Nitrate reductases (NRs) catalyze the first step in the reduction of nitrate to ammonium. NR activity is regulated by sumoylation through the E3 ligase activity of AtSIZ1. However, it is not clear how NRs interact with AtSIZ1 in the cell, or how nitrogen sources affect NR levels and their cellular localization. Here, we show that the subcellular localization of NRs is modulated by the E3 SUMO (Small ubiquitin-related modifier) ligase AtSIZ1 and that NR protein levels are regulated by nitrogen sources. Transient expression analysis of GFP fusion proteins in onion epidermal cells showed that the NRs NIA1 and NIA2 localize to the cytoplasmic membrane, and that AtSIZ1 localizes to the nucleoplasm, including nuclear bodies, when expressed separately, whereas NRs and AtSIZ1 localize to the nucleus when co-expressed. Nitrate did not affect the subcellular localization of the NRs, but it caused AtSIZ1 to move from the nucleus to the cytoplasm. NRs were not detected in ammonium-treated cells, whereas the localization of AtSIZ1 was not altered by ammonium treatment. NR protein levels increased in response to nitrate but decreased in response to ammonium. In addition, NR protein levels increased in response to a 26S proteasome inhibitor and in cop1-4 and DN-COP1-overexpressing transgenic plants. NR protein degradation occurred later in cop1-4 than in the wild-type, although the NR proteins did not interact with COP1. Therefore, AtSIZ1 controls nuclear localization of NR proteins, and ammonium negatively regulates their levels. The function and stability of NR proteins might be post-translationally modulated by ubiquitination.
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12
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Characterization and Potential Applications of a Selenium Nanoparticle Producing and Nitrate Reducing Bacterium Bacillus oryziterrae sp. nov. Sci Rep 2016; 6:34054. [PMID: 27677458 PMCID: PMC5039721 DOI: 10.1038/srep34054] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 09/02/2016] [Indexed: 01/29/2023] Open
Abstract
A novel nitrate- and selenite reducing bacterium strain ZYKT was isolated from a rice paddy soil in Dehong, Yunnan, China. Strain ZYKT is a facultative anaerobe and grows in up to 150, 000 ppm O2. The comparative genomics analysis of strain ZYKT implies that it shares more orthologues with B. subtilis subsp. subtilis NCIB 3610T (ANIm values, 85.4–86.7%) than with B. azotoformans NBRC 15712T (ANIm values, 84.4–84.7%), although B. azotoformans NBRC 15712T (96.3% 16S rRNA gene sequence similarity) is the closest Bacillus species according to 16S rRNA gene comparison. The major cellular fatty acids of strain ZYKT were iso-C14:0 (17.8%), iso-C15:0 (17.8%), and C16:0 (32.0%). The polar lipid profile consisted of phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol and an unidentified aminophospholipid. Based on physiological, biochemical and genotypic properties, the strain was considered to represent a novel species of the genus Bacillus, for which the name Bacillus oryziterrae sp. nov. is proposed. The type strain is ZYKT (=DSM 26460T =CGMCC 1.5179T). Strain ZYKT can reduce nitrate to nitrite and ammonium and possesses metabolic genes for nitrate reduction including nar, nap and nrf. Biogenic selenium nanoparticles of strain ZYKT show a narrow size distribution and agree with the gaussian distribution. These selenium nanoparticles show significant dose-dependent inhibition of the lung cancer cell line H157, which suggests potential for application in cancer therapy.
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13
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Gonzalez-Gil G, Lens PNL, Saikaly PE. Selenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres. Front Microbiol 2016; 7:571. [PMID: 27199909 PMCID: PMC4844624 DOI: 10.3389/fmicb.2016.00571] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 04/05/2016] [Indexed: 12/22/2022] Open
Abstract
Certain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se(0)), insights into the microbial community structure and synthesis of Se(0) within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20%) and Pseudomonadaceae (c.a.10%) were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (∼200 μm) of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se(0) (nano)spheres, with some cells having high numbers of intracellular Se(0) spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se(0) spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS) analysis of extracted Se(0) spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se(0) spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se(0) spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se(0) spheres. In view of these and previous findings, a schematic model for the synthesis of Se(0) spheres by the microorganisms inhabiting the granular sludge is proposed.
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Affiliation(s)
- Graciela Gonzalez-Gil
- Division of Biological and Environmental Sciences and Engineering, Water Desalination and Reuse Center, King Abdullah University of Science and TechnologyThuwal, Saudi Arabia; Department of Environmental Engineering and Water Technology, UNESCO-IHE Institute for Water EducationDelft, Netherlands
| | - Piet N L Lens
- Department of Environmental Engineering and Water Technology, UNESCO-IHE Institute for Water Education Delft, Netherlands
| | - Pascal E Saikaly
- Division of Biological and Environmental Sciences and Engineering, Water Desalination and Reuse Center, King Abdullah University of Science and Technology Thuwal, Saudi Arabia
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14
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Abstract
In nature, selenium is actively cycled between oxic and anoxic habitats, and this cycle plays an important role in carbon and nitrogen mineralization through bacterial anaerobic respiration. Selenium-respiring bacteria (SeRB) are found in geographically diverse, pristine or contaminated environments and play a pivotal role in the selenium cycle. Unlike its structural analogues oxygen and sulfur, the chalcogen selenium and its microbial cycling have received much less attention by the scientific community. This review focuses on microorganisms that use selenate and selenite as terminal electron acceptors, in parallel to the well-studied sulfate-reducing bacteria. It overviews the significant advancements made in recent years on the role of SeRB in the biological selenium cycle and their ecological role, phylogenetic characterization, and metabolism, as well as selenium biomineralization mechanisms and environmental biotechnological applications.
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Affiliation(s)
- Y V Nancharaiah
- Environmental Engineering and Water Technology Department, UNESCO-IHE Institute for Water Education, Delft, The Netherlands Biofouling and Biofilm Processes Section, Water and Steam Chemistry Division, Bhabha Atomic Research Centre, Kalpakkam, Tamil Nadu, India
| | - P N L Lens
- Environmental Engineering and Water Technology Department, UNESCO-IHE Institute for Water Education, Delft, The Netherlands
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15
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Transcriptional Response of Selenopolypeptide Genes and Selenocysteine Biosynthesis Machinery Genes in Escherichia coli during Selenite Reduction. Int J Microbiol 2014; 2014:394835. [PMID: 24839442 PMCID: PMC4009273 DOI: 10.1155/2014/394835] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Revised: 02/28/2014] [Accepted: 03/16/2014] [Indexed: 01/05/2023] Open
Abstract
Bacteria can reduce toxic selenite into less toxic, elemental selenium (Se0), but the mechanism on how bacterial cells reduce selenite at molecular level is still not clear. We used Escherichia coli strain K12, a common bacterial strain, as a model to study its growth response to sodium selenite (Na2SeO3) treatment and then used quantitative real-time PCR (qRT-PCR) to quantify transcript levels of three E. coli selenopolypeptide genes and a set of machinery genes for selenocysteine (SeCys) biosynthesis and incorporation into polypeptides, whose involvements in the selenite reduction are largely unknown. We determined that 5 mM Na2SeO3 treatment inhibited growth by ∼50% while 0.001 to 0.01 mM treatments stimulated cell growth by ∼30%. Under 50% inhibitory or 30% stimulatory Na2SeO3 concentration, selenopolypeptide genes (fdnG, fdoG, and fdhF) whose products require SeCys but not SeCys biosynthesis machinery genes were found to be induced ≥2-fold. In addition, one sulfur (S) metabolic gene iscS and two previously reported selenite-responsive genes sodA and gutS were also induced ≥2-fold under 50% inhibitory concentration. Our findings provide insight about the detoxification of selenite in E. coli via induction of these genes involved in the selenite reduction process.
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16
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Bao P, Su JQ, Hu ZY, Häggblom MM, Zhu YG. Genome sequence of the anaerobic bacterium Bacillus sp. strain ZYK, a selenite and nitrate reducer from paddy soil. Stand Genomic Sci 2014; 9:646-54. [PMID: 25197451 PMCID: PMC4148952 DOI: 10.4056/sigs.3817480] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Bacillus sp. strain ZYK, a member of the phylum Firmicutes, is of interest for its ability to reduce nitrate and selenite and for its resistance to arsenic under anaerobic conditions. Here we describe some key features of this organism, together with the complete genome sequence and annotation. The 3,575,797 bp long chromosome with its 3,454 protein-coding and 70 RNA genes, and the information gained from its sequence will be relevant to the elucidation of microbially-mediated transformations of nitrogen, selenium and arsenic in paddy soil.
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Affiliation(s)
- Peng Bao
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, P. R. China
| | - Jian-Qiang Su
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, P. R. China
| | - Zheng-Yi Hu
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Max M Häggblom
- Rutgers University, Department of Biochemistry and Microbiology, School of Environmental and Biological Sciences, New Brunswick, NJ, USA
| | - Yong-Guan Zhu
- State Key Lab of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, P. R. China ; Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, P. R. China
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