1
|
Wang Q, Zhang C, Song J, Bamanu B, Zhao Y. Inhibitory mechanism of Cr(VI) on sulfur-based denitrification: Bio-toxicity, bio-electron characteristics, and microbial evolution. JOURNAL OF HAZARDOUS MATERIALS 2024; 472:134447. [PMID: 38692000 DOI: 10.1016/j.jhazmat.2024.134447] [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: 02/09/2024] [Revised: 03/24/2024] [Accepted: 04/25/2024] [Indexed: 05/03/2024]
Abstract
Sulfur-based denitrification is a promising technology for efficient nitrogen removal in low-carbon wastewater, while it is easily affected by toxic substances. This study revealed the inhibitory mechanism of Cr(VI) on thiosulfate-based denitrification, including bio-toxicity and bio-electron characteristics response. The activity of nitrite reductase (NIR) was more sensitive to Cr(VI) than that of nitrate reductase (NAR), and NIR was inhibited by 21.32 % and 19.86 % under 5 and 10 mg/L Cr(VI), resulting in 10.12 and 15.62 mg/L of NO2--N accumulation. The biofilm intercepted 36.57 % of chromium extracellularly by increasing 25.78 % of extracellular polymeric substances, thereby protecting microbes from bio-toxicity under 5 mg/L Cr(VI). However, it was unable to resist 20-30 mg/L of Cr(VI) bio-toxicity as 19.95 and 14.29 mg Cr/(g volatile suspended solids) invaded intracellularly, inducing the accumulation of reactive oxygen species by 165.98 % and 169.12 %, which triggered microbial oxidative-stress and damaged the cells. In terms of electron transfer, S2O32- oxidation was inhibited, and parts of electrons were redirected intracellularly to maintain microbial activity, resulting in insufficient electron donors. Meanwhile, the contents of flavin adenine dinucleotide and cytochrome c decreased under 5-30 mg/L Cr(VI), reducing the electron acquisition rate of denitrification. Thermomonas (the dominant genus) possessed denitrification and Cr(VI) resistance abilities, playing an important role in antioxidant stress and biofilm formation. ENVIRONMENTAL IMPLICATION: Sulfur-based denitrification (SBD) is a promising method for nitrate removal in low-carbon wastewater, while toxic heavy metals such as Cr(VI) negatively impair denitrification. This study elucidated Cr(VI) inhibitory mechanisms on SBD, including bio-toxicity response, bio-electron characteristics, and microbial community structure. Higher concentrations Cr(VI) led to intracellular invasion and oxidative stress, evidenced by ROS accumulation. Moreover, Cr(VI) disrupted electron flow by inhibiting thiosulfate oxidation and affecting electron acquisition by denitrifying enzymes. This study provided valuable insights into Cr(VI) toxicity, which is of great significance for improving wastewater treatment technologies and maintaining efficient and stable operation of SBD in the face of complex environmental challenges.
Collapse
Affiliation(s)
- Qian Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Chenggong Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Jinxin Song
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Bibek Bamanu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China.
| |
Collapse
|
2
|
Zhao Y, Zhang J, Chen Z, Wang Q. Bio-promoter mediated denitrification recovery from Cd(II) stress: Microbial activity resilience, electron behavior enhancement and microbial community evolution. BIORESOURCE TECHNOLOGY 2024; 402:130780. [PMID: 38703963 DOI: 10.1016/j.biortech.2024.130780] [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: 02/14/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/06/2024]
Abstract
Denitrification is fragile to toxic substances, while currently there are few regulation strategies for toxic substance-stressed denitrification. This study proposed a combined bio-promoter composed of basic bio-promoter (cytokinin, biotin, L-cysteine, and flavin adenine dinucleotide) and phosphomolybdic acid (PMo12) to recover cadmium(II) (Cd(II)) stressed denitrification. By inhibiting 58.02% and 48.84% of nitrate reductase and nitrite reductase activities, Cd(II) caused all the influent nitrogen to accumulate as NO3--N and NO2--N. Combined bio-promoter shortened the recovery time by 21 cycles and improved nitrogen removal efficiency by 10% as the synergistic effect of basic bio-promoter and PMo12. Basic bio-promoter enhanced antioxidant enzyme activities for reactive oxygen species clearance and recovered 23.30% of nicotinamide adenine dinucleotide for sufficient electron donors. Meanwhile, PMo12 recovered electron carriers contents, increasing the electron transfer activity by 60.81% compared with self-recovery. Bio-promoters enhanced the abundance of denitrifiers Seminibacterium and Dechloromonas, which was positively correlated with rapid recovery of denitrification performance.
Collapse
Affiliation(s)
- Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Jinshuang Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Zhihui Chen
- China Water Resources Bei Fang Investigation, Design & Research CO.LTD, China
| | - Qian Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China.
| |
Collapse
|
3
|
Wu M, Xu Y, Zhao C, Huang H, Liu C, Duan X, Zhang X, Zhao G, Chen Y. Efficient nitrate and Cr(VI) removal by denitrifier: The mechanism of S. oneidensis MR-1 promoting electron production, transportation and consumption. JOURNAL OF HAZARDOUS MATERIALS 2024; 469:133675. [PMID: 38508109 DOI: 10.1016/j.jhazmat.2024.133675] [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: 12/18/2023] [Revised: 01/21/2024] [Accepted: 01/29/2024] [Indexed: 03/22/2024]
Abstract
When Cr(VI) and nitrate coexist, the efficiency of both bio-denitrification and Cr(VI) bio-reduction is poor because chromate hinders bacterial normal functions (i.e., electron production, transportation and consumption). Moreover, under anaerobic condition, the method about efficient nitrate and Cr(VI) removal remained unclear. In this paper, the addition of Shewanella oneidensis MR-1 to promote the electron production, transportation and consumption of denitrifier and cause an increase in the removal of nitrate and Cr(VI). The efficiency of nitrate and Cr(VI) removal accomplished by P. denitrificans as a used model denitrifier increased respectively from 51.3% to 96.1% and 34.3% to 99.8% after S. oneidensis MR-1 addition. The mechanism investigations revealed that P. denitrificans provided S. oneidensis MR-1 with lactate, which was utilized to secreted riboflavin and phenazine by S. oneidensis MR-1. The riboflavin served as coenzymes of cellular reductants (i.e., thioredoxin and glutathione) in P. denitrificans, which created favorable intracellular microenvironment conditions for electron generation. Meanwhile, phenazine promoted biofilm formation, which increased the adsorption of Cr(VI) on the cell surface and accelerated the Cr(VI) reduction by membrane bound chromate reductases thereby reducing damage to other enzymes respectively. Overall, this strategy reduced the negative effect of chromate, thus improved the generation, transportation, and consumption of electrons. SYNOPSIS: The presence of S. oneidensis MR-1 facilitated nitrate and Cr(VI) removal by P. denitrificans through decreasing the negative effect of chromate due to the metabolites' secretion.
Collapse
Affiliation(s)
- Meirou Wu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yanan Xu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Chunxia Zhao
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Haining Huang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Chao Liu
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xu Duan
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xuemeng Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Guohua Zhao
- School of Chemical Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
| |
Collapse
|
4
|
Wang Q, Zhao Y, Liu Y, Zhang C, Bamanu B, Wu Y, Chao C, Liu Y, Tong Y, Nuramkhaan M. Recovery mechanism of bio-promoters on Cr(VI) suppressed denitrification: Toxicity remediation and enhanced electron transmission. WATER RESEARCH 2024; 252:121230. [PMID: 38330714 DOI: 10.1016/j.watres.2024.121230] [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: 09/18/2023] [Revised: 12/31/2023] [Accepted: 01/28/2024] [Indexed: 02/10/2024]
Abstract
Although the biotoxicity of heavy metals has been widely studied, there are few reports on the recovery strategy of the inhibited bio-system. This study proposed a combined promoter-I (Primary promoter: l-cysteine, biotin, and cytokinin + Electron-shuttle: PMo12) to recover the denitrification suppressed by Cr(VI). Compared with self-recovery, combined promoter-I shortened the recovery time of 28 cycles, and the recovered reactor possessed more stable long-term operation performance with >95 % nitrogen removal. The biomass increased by 7.07 mg VSS/(cm3 carrier) than self-recovery due to the promoted bacterial reproduction, thereby reducing the toxicity load of chromium per unit biomass. The combined promoter-I strengthened the toxicity remediation by promoting 92.84 % of the intracellular chromium release and rapidly activating anti-oxidative stress response. During toxicity remediation, ROS content quickly decreased, and the PN/PS value was 2.27 times that of self-recovery. PMo12 relieved Cr(VI) inhibition on NO3--N reduction by increasing NAR activity. The enhanced intracellular and intercellular electron transmission benefited from the stimulated NADH, FMN, and Cyt.c secretion by the primary promoter and the improved transmembrane electron transmission by Mo. PMo12 and the primary promoter synergized in regulating community structure and improving microbial richness. This study provided practical approaches for microbial toxicity remediation and maintaining high-efficiency denitrification.
Collapse
Affiliation(s)
- Qian Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China.
| | - Yinuo Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Chenggong Zhang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Bibek Bamanu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Yichen Wu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Chunfang Chao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Yindong Tong
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300350, China
| | - Marjangul Nuramkhaan
- Laboratory of Microbiology, Institute of Biology, Mongolian Academy of Sciences, Peace avenue-54b, Ulaanbaatar, Mongolia
| |
Collapse
|
5
|
Rastkhah E, Fatemi F, Maghami P. Optimizing the Metal Bioreduction Process in Recombinant Shewanella azerbaijanica Bacteria: A Novel Approach via mtrC Gene Cloning and Nitrate-Reducing Pathway Destruction. Mol Biotechnol 2023:10.1007/s12033-023-00920-x. [PMID: 37917324 DOI: 10.1007/s12033-023-00920-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 09/22/2023] [Indexed: 11/04/2023]
Abstract
Environmental pollution is growing every day in terms of the increase in population, industrialization, and urbanization. Shewanella azerbaijanica is introduced as a highly potent bacterium in metal bioremediation. The mtrC gene was selected as a cloning target to improve electron flux chains in the EET (extracellular electron transfer) pathway. Using the SDM (site-directed mutagenesis) technique, the unique gene assembly featured the mtrC gene sandwiched between two napD/B genes to disrupt the nitrate reduction pathway, which serves as the primary metal reduction competitor. Shew-mtrC gene construction was transferred to expression plasmid pET28a (+) in the expression host bacteria (E. coli BL21 and S. azerbaijanica), in pUC57, cloning plasmid, which was transferred to the cloning host bacteria E. coli Top10 and S. azerbaijanica. All cloning procedures (i.e., synthesis, insertion, transformation, cloning, and protein expression) were verified and confirmed by precise tests. ATR-FTIR analysis, CD, western blotting, affinity chromatography, SDS-PAGE, and other techniques were used to confirm the expression and structure of the MtrC protein. The genome sequence and primers were designed according to the submitted Shewanella oneidensis MR-1 genome, the most similar bacteria to this native species. The performance of recombinant S. azerbaijanica bacterium in metal bioremediation, as sustainable strategy, has to be verified by more research.
Collapse
Affiliation(s)
- Elham Rastkhah
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Faezeh Fatemi
- Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.
| | - Parvaneh Maghami
- Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| |
Collapse
|
6
|
Wen Z, Liu Q, Yu C, Huang L, Liu Y, Xu S, Li Z, Liu C, Feng Y. The Difference between Rhizosphere and Endophytic Bacteria on the Safe Cultivation of Lettuce in Cr-Contaminated Farmland. TOXICS 2023; 11:371. [PMID: 37112598 PMCID: PMC10146757 DOI: 10.3390/toxics11040371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 06/19/2023]
Abstract
Chromium (Cr) is a major pollutant affecting the environment and human health and microbial remediation is considered to be the most promising technology for the restoration of the heavily metal-polluted soil. However, the difference between rhizosphere and endophytic bacteria on the potential of crop safety production in Cr-contaminated farmland is not clearly elucidated. Therefore, eight Cr-tolerant endophytic strains of three species: Serratia (SR-1~2), Lysinebacillus (LB-1~5) and Pseudomonas (PA-1) were isolated from rice and maize. Additionally, one Cr-tolerant strain of Alcaligenes faecalis (AF-1) was isolated from the rhizosphere of maize. A randomized group pot experiment with heavily Cr-contaminated (a total Cr concentration of 1020.18 mg kg-1) paddy clay soil was conducted and the effects of different bacteria on plant growth, absorption and accumulation of Cr in lettuce (Lactuca sativa var. Hort) were compared. The results show that: (i) the addition of SR-2, PA-1 and LB-5 could promote the accumulation of plant fresh weight by 10.3%, 13.5% and 14.2%, respectively; (ii) most of the bacteria could significantly increase the activities of rhizosphere soil catalase and sucrase, among which LB-1 promotes catalase activity by 224.60% and PA-1 increases sucrase activity by 247%; (iii) AF-1, SR-1, LB-1, SR-2, LB-2, LB-3, LB-4 and LB-5 strains could significantly decrease shoot the Cr concentration by 19.2-83.6%. The results reveal that Cr-tolerant bacteria have good potential to reduce shoot Cr concentration at the heavily contaminated soil and endophytic bacteria have the same or even better effects than rhizosphere bacteria; this suggests that bacteria in plants are more ecological friendly than bacteria in soil, thus aiming to safely produce crops in Cr-polluted farmland and alleviate Cr contamination from the food chain.
Collapse
Affiliation(s)
- Zheyu Wen
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Qizhen Liu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chao Yu
- Livestock Industrial Development Center of Shengzhou, Shaoxing 312400, China
| | - Lukuan Huang
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yaru Liu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Shun’an Xu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Zhesi Li
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chanjuan Liu
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Ying Feng
- MOE Key Laboratory of Environment Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China
| |
Collapse
|
7
|
Effects of UV stress on Shewanella azerbaijanica bioremediation response. RADIOCHIM ACTA 2022. [DOI: 10.1515/ract-2022-0059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Abstract
Shewanella azerbaijanica roles as a live electrode, passing electrons from electron donors to electron acceptors, to gain energy from the extracellular electron transfer (EET) pathway. The present study, considered the quantitative expressions of the major EET reductase genes (mtr cluster), together with uranium removal, live-cell counting, and spectrophotometry in UV-C treated bacteria (0, 60, 120 and 180 s). The simultaneous decline in the uranium removal and cell counting, along with major mtr gene expression patterns (mtrABDEF), approved the negative effects of UV-C radiation on uranium bioreduction in S. azerbaijanica. Uranium removal and cell counting decreased to 25.49% and 0.45 × 109 cells/mL in the 180s UV-C treated sample, respectively at 2 mM uranium concentration, while no decline trend found in 0.5 mM for the counted cells and uranium removal tests. No considerable expression of omcA and omcB (mtrC) genes were traced due to spontaneous mutagenesis during the in vitro serial passages, proposing a novel alternative EET pathway in S. azerbaijanica during uranium bioreduction process. The results could pave the way for further researches to modify the bioremediation process through genetic manipulation.
Collapse
|
8
|
Goff JL, Szink EG, Thorgersen MP, Putt AD, Fan Y, Lui LM, Nielsen TN, Hunt KA, Michael JP, Wang Y, Ning D, Fu Y, Van Nostrand JD, Poole FL, Chandonia J, Hazen TC, Stahl DA, Zhou J, Arkin AP, Adams MWW. Ecophysiological and genomic analyses of a representative isolate of highly abundant Bacillus cereus strains in contaminated subsurface sediments. Environ Microbiol 2022; 24:5546-5560. [PMID: 36053980 PMCID: PMC9805006 DOI: 10.1111/1462-2920.16173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 08/10/2022] [Indexed: 01/09/2023]
Abstract
Bacillus cereus strain CPT56D-587-MTF (CPTF) was isolated from the highly contaminated Oak Ridge Reservation (ORR) subsurface. This site is contaminated with high levels of nitric acid and multiple heavy metals. Amplicon sequencing of the 16S rRNA genes (V4 region) in sediment from this area revealed an amplicon sequence variant (ASV) with 100% identity to the CPTF 16S rRNA sequence. Notably, this CPTF-matching ASV had the highest relative abundance in this community survey, with a median relative abundance of 3.77% and comprised 20%-40% of reads in some samples. Pangenomic analysis revealed that strain CPTF has expanded genomic content compared to other B. cereus species-largely due to plasmid acquisition and expansion of transposable elements. This suggests that these features are important for rapid adaptation to native environmental stressors. We connected genotype to phenotype in the context of the unique geochemistry of the site. These analyses revealed that certain genes (e.g. nitrate reductase, heavy metal efflux pumps) that allow this strain to successfully occupy the geochemically heterogenous microniches of its native site are characteristic of the B. cereus species while others such as acid tolerance are mobile genetic element associated and are generally unique to strain CPTF.
Collapse
Affiliation(s)
- Jennifer L. Goff
- Department of Biochemistry and Molecular BiologyUniversity of GeorgiaAthensGeorgiaUSA
| | - Elizabeth G. Szink
- Department of Biochemistry and Molecular BiologyUniversity of GeorgiaAthensGeorgiaUSA
| | - Michael P. Thorgersen
- Department of Biochemistry and Molecular BiologyUniversity of GeorgiaAthensGeorgiaUSA
| | - Andrew D. Putt
- Earth and Planetary SciencesUniversity of TennesseeKnoxvilleTennesseeUSA
| | - Yupeng Fan
- Institute for Environmental GenomicsUniversity of OklahomaNormanOklahomaUSA
| | - Lauren M. Lui
- Environmental Genomics and Systems Biology DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - Torben N. Nielsen
- Environmental Genomics and Systems Biology DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - Kristopher A. Hunt
- Civil and Environmental EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | | | - Yajiao Wang
- Institute for Environmental GenomicsUniversity of OklahomaNormanOklahomaUSA
| | - Daliang Ning
- Institute for Environmental GenomicsUniversity of OklahomaNormanOklahomaUSA
| | - Ying Fu
- Institute for Environmental GenomicsUniversity of OklahomaNormanOklahomaUSA
| | | | - Farris L. Poole
- Department of Biochemistry and Molecular BiologyUniversity of GeorgiaAthensGeorgiaUSA
| | - John‐Marc Chandonia
- Environmental Genomics and Systems Biology DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA
| | - Terry C. Hazen
- Earth and Planetary SciencesUniversity of TennesseeKnoxvilleTennesseeUSA,Genome Sciences DivisionOak Ridge National LabOak RidgeTennesseeUSA,Department of Civil and Environmental EngineeringUniversity of TennesseeKnoxvilleTennesseeUSA
| | - David A. Stahl
- Civil and Environmental EngineeringUniversity of WashingtonSeattleWashingtonUSA
| | - Jizhong Zhou
- Institute for Environmental GenomicsUniversity of OklahomaNormanOklahomaUSA,Department of Microbiology and Plant BiologyUniversity of OklahomaNormanOklahomaUSA,School of Civil Engineering and Environmental SciencesUniversity of OklahomaNormanOklahomaUSA,Earth and Environmental SciencesLawrence Berkley National LaboratoryBerkeleyCaliforniaUSA
| | - Adam P. Arkin
- Environmental Genomics and Systems Biology DivisionLawrence Berkeley National LaboratoryBerkeleyCaliforniaUSA,Department of BioengineeringUniversity of California at BerkeleyBerkeleyCaliforniaUSA
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular BiologyUniversity of GeorgiaAthensGeorgiaUSA
| |
Collapse
|
9
|
Role of Exopolysaccharides of Pseudomonas in Heavy Metal Removal and Other Remediation Strategies. Polymers (Basel) 2022; 14:polym14204253. [PMID: 36297831 PMCID: PMC9609410 DOI: 10.3390/polym14204253] [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: 09/14/2022] [Revised: 10/05/2022] [Accepted: 10/07/2022] [Indexed: 11/30/2022] Open
Abstract
Pseudomonas biofilms have been studied intensively for several decades and research outcomes have been successfully implemented in various medical and agricultural applications. Research on biofilm synthesis and composition has also overlapped with the objectives of environmental sciences, since biofilm components show exceptional physicochemical properties applicable to remediation techniques. Especially, exopolysaccharides (ExPs) have been at the center of scientific interest, indicating their potential in solving the environmental issues of heavy metal land and water contamination via sorptive interactions and flocculation. Since exposure to heavy metal via contaminated water or soil poses an imminent risk to the environment and human health, ExPs provide an interesting and viable solution to this issue, alongside other effective and green remedial techniques (e.g., phytostabilization, implementation of biosolids, and biosorption using agricultural wastes) aiming to restore contaminated sites to their natural, pollution-free state, or to ameliorate the negative impact of heavy metals on the environment. Thus, we discuss the plausible role and performance of Pseudomonas ExPs in remediation techniques, aiming to provide the relevant available and comprehensive information on ExPs’ biosynthesis and their usage in heavy metal remediation or other environmental applications, such as wastewater treatment via bioflocculation and soil remediation.
Collapse
|
10
|
Shen L, Ding W, Li X, Zhang Y, Cong Y. Fabrication of 3D self-supported MoS 2-Co-P/nickel foam electrode for adsorption-electrochemical removal of Cr(Ⅵ). CHEMOSPHERE 2022; 304:135209. [PMID: 35667509 DOI: 10.1016/j.chemosphere.2022.135209] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/10/2022] [Accepted: 05/31/2022] [Indexed: 06/15/2023]
Abstract
Electrochemistry is considered to be one of the most efficient and environment-friendly methods for removing highly toxic Cr (Ⅵ). In this study, a 3D self-supported MoS2-Co-P/nickel foam (NF) electrode was prepared via a calcination-hydrothermal process to remove the Cr (Ⅵ) in aqueous medium. Scanning electron microscope (SEM) analysis indicated that the pine-needle-like Co2P nanoneedle and flower-like MoS2 nanosheets were successfully loaded on the three-dimensional (3D) framework of NF, which provided abundant active sites. The electrode modified by Co, P and MoS2 exhibited high removal efficiency of Cr (Ⅵ) (96.9%) at pH 3.0, current of 0.128 mA and voltage of 2.5 V. Co, P and MoS2 have the synergistic promotion on the catalytic performance of electrodes, and the reduction efficiency of Cr (Ⅵ) was greatly improved by 127.5 times relative to pure NF. The enhanced removal of Cr (Ⅵ) was related to the coupling effect of adsorption and electrocatalytic reduction. The mechanism study indicated that electron (e-) is the active species of Cr (Ⅵ) reduction. The Cr (Ⅵ) removal rate was maintained at 90 ± 1% after five successive cycle experiments, demonstrating good stability and potential industrial applications of MoS2-Co-P/NF.
Collapse
Affiliation(s)
- Lidong Shen
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Wenchen Ding
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Xuchun Li
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Yi Zhang
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China
| | - Yanqing Cong
- School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China.
| |
Collapse
|
11
|
Murthy MK, Khandayataray P, Samal D. Chromium toxicity and its remediation by using endophytic bacteria and nanomaterials: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 318:115620. [PMID: 35772275 DOI: 10.1016/j.jenvman.2022.115620] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/13/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Chromium (Cr) is a crucial element for all life forms. Various anthropogenic activities have been responsible for environmental contamination with Cr (VI) in recent years. For this review, articles were collected using electronic databases such as Web of Science, Pubmed, ProQuest, and Google Scholar as per the guidelines of PRISMA-2015, applying the Boolean search methods. Chromium can cause severe health complications in humans and animals and threatens the surrounding environment, with negative impacts on crop yield, development, and quality. Hence, monitoring Cr contamination is essential, and various remediation technologies have emerged in the past 50 years to reduce the amount of Cr in the environment. This review focuses on chromium exposure and the associated environmental health risks. We also reviewed sustainable remediation processes, with emphasis on nanoparticle and endophytic remediation processes.
Collapse
Affiliation(s)
| | | | - Dibyaranjan Samal
- Department of Biotechnology, Academy of Management and Information Technology, VidyaVihar, IID Center, Khordha, Odisha, India
| |
Collapse
|
12
|
Ashun E, Kang W, Thapa BS, Gurung A, Rahimnejad M, Jang M, Jeon BH, Kim JR, Oh SE. A novel gas production bioassay of thiosulfate utilizing denitrifying bacteria (TUDB) for the toxicity assessment of heavy metals contaminated water. CHEMOSPHERE 2022; 303:134902. [PMID: 35561773 DOI: 10.1016/j.chemosphere.2022.134902] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/25/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
This study reports for the first-time the possibility of deploying gas production by thiosulfate utilizing denitrifying bacteria (TUDB) as a proxy to evaluate water toxicity. The test relies on gas production by TUDB due to inhibited metabolic activity in the presence of toxicants. Gas production was measured using a bubble-type respirometer. Optimization studies indicated that 300 mg NO3--N/L, 0.5 mL acclimated culture, and 2100 mg S2O32-/L were the ideal conditions facilitating the necessary volume of gas production for sensitive data generation. Determined EC50 values of the selected heavy metals were: Cr6+, 0.51 mg/L; Ag+, 2.90 mg/L; Cu2+, 2.90 mg/L; Ni2+, 3.60 mg/L; As3+, 4.10 mg/L; Cd2+, 5.56 mg/L; Hg2+, 8.06 mg/L; and Pb2+, 19.3 mg/L. The advantages of this method include operational simplicity through the elimination of cumbersome preprocessing procedures which are used to eliminate interferences caused by turbidity when the toxicity of turbid samples is determined via spectrophotometry.
Collapse
Affiliation(s)
- Ebenezer Ashun
- Department of Biological Environment, Kangwon National University, 192-1 Hyoja-dong, Gangwon-do, Chuncheon-si, 200-701, Republic of Korea
| | - Woochang Kang
- Department of Biological Environment, Kangwon National University, 192-1 Hyoja-dong, Gangwon-do, Chuncheon-si, 200-701, Republic of Korea
| | - Bhim Sen Thapa
- Department of Biological Environment, Kangwon National University, 192-1 Hyoja-dong, Gangwon-do, Chuncheon-si, 200-701, Republic of Korea
| | - Anup Gurung
- Department of Biological Environment, Kangwon National University, 192-1 Hyoja-dong, Gangwon-do, Chuncheon-si, 200-701, Republic of Korea
| | - Mostafa Rahimnejad
- Biofuel and Renewable Energy Research Center, Chemical Engineering Department, Babol Noshirvani University of Technology, Babol, Islamic Republic of Iran
| | - Min Jang
- Department of Environmental Engineering, Kwangwoon University, 20 Kwangwoon-Ro, Nowon-Gu, Seoul 01897, Republic of Korea
| | - Byong-Hun Jeon
- Department of Earth Resources and Environmental Engineering, Hanyang University, Seoul 04763, Republic of Korea
| | - Jung Rae Kim
- School of Chemical Engineering, Pusan National University, 63 Busandeahak-ro, Geumjeong-Gu, Busan 46241, Republic of Korea
| | - Sang-Eun Oh
- Department of Biological Environment, Kangwon National University, 192-1 Hyoja-dong, Gangwon-do, Chuncheon-si, 200-701, Republic of Korea.
| |
Collapse
|
13
|
Applying the Nernst Equation to Control ORP in Denitrification Process for Uranium-Containing Nuclear Effluent with High Loads of Nitrogen and COD. WATER 2022. [DOI: 10.3390/w14142227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Several reviews of denitrification have shown it to be an efficient process for treating high nitrate-loaded effluents from nuclear industries. However, stressful conditions adversely affect biological kinetic parameters and performance. Additionally, actual nuclear effluents contain multiple pollutants and radioactive emissions that could render implementation difficult. The objective of this study was to treat and recycle water from nuclear industries by using a mixture of blended real nuclear wastewater (BRNW). The process was carried out under physicochemical parameters control in a biological model to established a technical setup and to model the denitrification process in a real nuclear wastewater effluent. Denitrification processes were carried out in the wastewater sample under controlled ORP conditions by the Hill model to establish the kinetic model. The results show a complete elimination of nitrate by the bacteria. Indicators of biochemical reactions were used to obtain a model based on Monod and controlled ORP. The good fit of the proposed model was verified under empirical and simulated conditions. To establish optimal performance, it was necessary to add 3% v/v of methanol, as a carbon source, to remove the nitrate in BRNW. Isolation techniques confirmed that Pseudomonas spp. was the dominant bacteria. Gene expression demonstrated the lack of inhibition of the NosZ gene responsible for the reduction in nitric oxide, a “greenhouse gas”. Finally, COD and uranium were removed from the liquid by precipitation. At the end of the process, the treated effluent could potentially be reused in industrial processes, recycling most of the wastewater effluents.
Collapse
|
14
|
Study of the performance of a bloom-forming cyanobacterium (Microcystis aeruginosa) on the biosorption of uranium. J Radioanal Nucl Chem 2022. [DOI: 10.1007/s10967-022-08384-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
15
|
The Interplay of Iron Minerals and Microflora to Accelerate Cr (VI) Reduction. MINERALS 2022. [DOI: 10.3390/min12040460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Widespread hexavalent chromium (Cr (VI)) in the environment has become a worldwide problem, and economical and efficient treatment is urgently needed. In this paper, the treatment method of Cr (VI) by microorganisms and iron minerals (pyrite and magnetite) under anaerobic conditions was investigated. Furthermore, the influence of Cr (VI) on the microbial community structure was explored. The reduction test demonstrated that the removal rate of Cr (VI) in a single biological group was 54.96%; however, in the pyrite and biological groups and magnetite and biological groups, the removal rates of Cr (VI) increased to 83.06% and 78.23%, respectively. Microorganisms and iron minerals work together to produce a better removal effect on the removal rate of Cr (VI). Mechanistic studies have found that in the process of Cr (VI) reduction, a passivation layer is formed on the surface of the mineral that hinders the progress of the reaction. The addition of bacteria can reduce the negative impact of the passivation layer. At the same time, iron minerals have better electron-receiving and -conducting ability and can be used as electron carriers for bacteria to reduce Cr (VI). In addition, iron minerals and the disappearance of Cr (VI) will change the structure of the community and affect the expression of its functions, which is more conducive to reducing Cr (VI). This work sheds new light on the treatment of heavy metal pollution and the understanding of the synergistic reduction mechanism of Cr (VI).
Collapse
|
16
|
Deciphering Microbial Metal Toxicity Responses via Random Bar Code Transposon Site Sequencing and Activity-Based Metabolomics. Appl Environ Microbiol 2021; 87:e0103721. [PMID: 34432491 DOI: 10.1128/aem.01037-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To uncover metal toxicity targets and defense mechanisms of the facultative anaerobe Pantoea sp. strain MT58 (MT58), we used a multiomic strategy combining two global techniques, random bar code transposon site sequencing (RB-TnSeq) and activity-based metabolomics. MT58 is a metal-tolerant Oak Ridge Reservation (ORR) environmental isolate that was enriched in the presence of metals at concentrations measured in contaminated groundwater at an ORR nuclear waste site. The effects of three chemically different metals found at elevated concentrations in the ORR contaminated environment were investigated: the cation Al3+, the oxyanion CrO42-, and the oxycation UO22+. Both global techniques were applied using all three metals under both aerobic and anaerobic conditions to elucidate metal interactions mediated through the activity of metabolites and key genes/proteins. These revealed that Al3+ binds intracellular arginine, CrO42- enters the cell through sulfate transporters and oxidizes intracellular reduced thiols, and membrane-bound lipopolysaccharides protect the cell from UO22+ toxicity. In addition, the Tol outer membrane system contributed to the protection of cellular integrity from the toxic effects of all three metals. Likewise, we found evidence of regulation of lipid content in membranes under metal stress. Individually, RB-TnSeq and metabolomics are powerful tools to explore the impact various stresses have on biological systems. Here, we show that together they can be used synergistically to identify the molecular actors and mechanisms of these pertubations to an organism, furthering our understanding of how living systems interact with their environment. IMPORTANCE Studying microbial interactions with their environment can lead to a deeper understanding of biological molecular mechanisms. In this study, two global techniques, RB-TnSeq and activity metabolomics, were successfully used to probe the interactions between a metal-resistant microorganism, Pantoea sp. strain MT58, and metals contaminating a site where the organism can be located. A number of novel metal-microbe interactions were uncovered, including Al3+ toxicity targeting arginine synthesis, which could lead to a deeper understanding of the impact Al3+ contamination has on microbial communities as well as its impact on higher-level organisms, including plants for whom Al3+ contamination is an issue. Using multiomic approaches like the one described here is a way to further our understanding of microbial interactions and their impacts on the environment overall.
Collapse
|
17
|
Syed A, Zeyad MT, Shahid M, Elgorban AM, Alkhulaifi MM, Ansari IA. Heavy Metals Induced Modulations in Growth, Physiology, Cellular Viability, and Biofilm Formation of an Identified Bacterial Isolate. ACS OMEGA 2021; 6:25076-25088. [PMID: 34604686 PMCID: PMC8482775 DOI: 10.1021/acsomega.1c04396] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 09/07/2021] [Indexed: 05/17/2023]
Abstract
The release of untreated tannery effluents comprising biotoxic heavy metal (HM) compounds into the ecosystem is one of our society's most serious environmental and health issues. After discharge, HM-containing industrial effluents reach agricultural soils and thus negatively affect the soil microbial diversity. Considering these, we assessed the effect of HMs on identified soil beneficial bacteria. Here, the effects of four heavy metals (HMs), viz., chromium (Cr), cadmium (Cd), nickel (Ni), and lead (Pb), on cellular growth, physiology, cell permeability, and biofilm formation of Enterobacter cloacae MC9 (accession no.: MT672587) were evaluated. HMs in a concentration range of 25-200 μg mL-1 were used throughout the study. Among HMs, Cd in general had the maximum detrimental effect on bacterial physiology. With increasing concentrations of HMs, bacterial activities consistently decreased. For instance, 200 μgCr mL-1 concentration greatly and significantly (p ≤ 0.05) reduced the synthesis of indole-3-acetic acid (IAA) by 70% over control. Furthermore, 200 μg mL-1 Cd maximally and significantly (p ≤ 0.05) reduced the synthesis of 2,3-dihydroxybenzoic acid (2,3-DHBA), salicylic acid (SA), 1-aminocyclopropane 1-carboxylate (ACC) deaminase, and extra polymeric substances (EPSs) of E. cloacae MC9 by 80, 81, 77, and 59%, respectively, over control. While assessing the toxic effect of HMs on the P-solubilizing activity of E. cloacae, the toxicity pattern followed the order Cr (mean value = 94.6 μg mL-1) > Cd (mean value = 127.2 μg mL-1) > Pb (mean value = 132.4 μg mL-1) > Ni (mean value = 140.4 μg mL-1). Furthermore, the colony-forming unit (CFU) count (Log10) of strain MC9 was completely inhibited at 150, 175, and 200 μg mL-1 concentrations of Cr and Cd. The confocal laser scanning microscopic (CLSM) analysis of HM-treated bacterial cells showed an increased number of red-colored dead cells as the concentration of HMs increased from 25 to 200 μg mL-1. Likewise, the biofilm formation ability of strain MC9 was maximally (p ≤ 0.05) inhibited at higher concentrations of Cd. In summary, the present investigation undoubtedly suggests that E. cloacae strain MC9 recovered from the HM-contaminated rhizosphere endowed with multiple activities could play an important role in agricultural practices to augment crop productivity in soils contaminated with HMs. Also, there is an urgent need to control the direct discharge of industrial waste into running water to minimize heavy metal pollution. Furthermore, before the application of HMs in agricultural fields, their appropriate field dosages must be carefully monitored.
Collapse
Affiliation(s)
- Asad Syed
- Department
of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Mohammad Tarique Zeyad
- Department
of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh, India
| | - Mohammad Shahid
- Department
of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, Uttar Pradesh, India
| | - Abdallah M. Elgorban
- Department
of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Manal M. Alkhulaifi
- Department
of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia
| | - Irfan Aamer Ansari
- Department
of Drug Science and Technology, University
of Turin, Turin 10124, Italy
| |
Collapse
|
18
|
Pushkar B, Sevak P, Parab S, Nilkanth N. Chromium pollution and its bioremediation mechanisms in bacteria: A review. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 287:112279. [PMID: 33706095 DOI: 10.1016/j.jenvman.2021.112279] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 02/10/2021] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
Environment pollution is at its peak and is creating havoc for living beings. Industrial wastes containing toxic pollutants have contributed to a great extent in this disastrous environment pollution. Chromium (Cr3+/Cr6+) is highly toxic and one of the most common environmental pollutants because of its extensive use in industries especially tanneries. Lack of efficient treatment methods has resulted in extensive chromium pollution. Bioremediation of chromium using bacteria is very thoughtful due to its eco-friendly and cost-effective outcome. Bacteria possess numerous mechanisms such as biosorption, reduction, efflux or bioaccumulation, naturally or acquired to counter the toxicity of chromium. This review focuses on the bacterial responses against chromium toxicity and scope for their application in bioremediation. The differences and similarities between Gram negative and positive bacteria against chromium are also highlighted. Further, the knowledge gap and future prospects are also discussed in order to fill these gaps and overcome the problem associated with real-time applicability of bacterial bioremediation.
Collapse
Affiliation(s)
- Bhupendra Pushkar
- Department of Biotechnology, University of Mumbai, Kalina, Santacruz (E), Mumbai, 400098, Maharashtra, India; Global Biotech Forum, Maharashtra, India.
| | - Pooja Sevak
- Department of Biotechnology, University of Mumbai, Kalina, Santacruz (E), Mumbai, 400098, Maharashtra, India; Society for Innovations in Biosciences, Maharashtra, India
| | - Sejal Parab
- Department of Biotechnology, University of Mumbai, Kalina, Santacruz (E), Mumbai, 400098, Maharashtra, India
| | - Nikita Nilkanth
- Department of Biotechnology, University of Mumbai, Kalina, Santacruz (E), Mumbai, 400098, Maharashtra, India
| |
Collapse
|
19
|
Burger A, Weidinger M, Baumann N, Vesely A, Lichtscheidl I. The response of the accumulator plants Noccaea caerulescens, Noccaea goesingense and Plantago major towards the uranium. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 229-230:106544. [PMID: 33556790 DOI: 10.1016/j.jenvrad.2021.106544] [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: 08/04/2020] [Revised: 01/21/2021] [Accepted: 01/23/2021] [Indexed: 06/12/2023]
Abstract
Uranium (U) is a naturally occurring metal; its environmental levels can be increased due to processes in the nuclear industry and fertilizer production. The transfer of U in the food chain from plants is associated with deleterious chemical and radiation effects. To date, limited information is available about U toxicity on plant physiology. This study investigates the responses of metal-accumulating plants to different concentrations of U. The plants Noccaea caerulescens and Noccaea goesingense are known as metal hyperaccumulators and therefore could serve as candidates for the phytoremediation of radioactive hotspots; Plantago major is a widely used pharmaceutical plant that pioneers polluted grounds and therefore should not contain high concentrations of toxic elements. The experimental plants were grown hydroponically at U concentrations between 1 μM and 10 mM. The content of U and essential elements was analyzed in roots and leaves by ICP-MS. The amount of accumulated U was influenced by its concentration in the hydroponics. Roots contained most of the metal, whereas less was transported up to the leaves, with the exception of N. goesingense in a medium concentration of U. U also influenced the nutrient profile of the plants. We localized the U in plant tissues using EDX in the SEM. U was evenly distributed in roots and leaves of Noccaea species, with one exception in the roots of N. goesingense, where the central cylinder contained more U than the cortex. The toxicity of U was assessed by measuring growth and photosynthetic parameters. While root biomass of N. caerulescens was not affected by U, root biomass of N. goesingense decreased significantly at high U concentrations of 0.1 and 10 mM and root biomass of P. major decreased at 10 mM U. Dry weight of leaves was decreased at different U concentrations in the three plant species; a promotive effect was observed in N. caerulescens at lowest concentration offered. Chlorophyll a fluorescence was not affected or negatively affected by U in both Noccaea species, whereas in Plantago also positive effects were observed. Our results show that the impact of U on Plantago and Noccaea relates to its external concentration and to the plant species. When growing in contaminated areas, P. major should not be used for medicinal purpose. Noccaea species and P. major could immobilize U in their rhizosphere in hotspots contaminated by U, and they could extract limited amounts of U into their leaves.
Collapse
Affiliation(s)
- Anna Burger
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstraße 14, 1090, Vienna, Austria.
| | - Marieluise Weidinger
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstraße 14, 1090, Vienna, Austria
| | - Nils Baumann
- Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstraße 400, 01328, Dresden, Germany
| | - Andreas Vesely
- Nuclear Engineering Seibersdorf GmbH, 2444, Seibersdorf, Austria
| | - Irene Lichtscheidl
- Cell Imaging and Ultrastructure Research, University of Vienna, Althanstraße 14, 1090, Vienna, Austria
| |
Collapse
|
20
|
Wang B, Li Y, Zheng J, Hu Y, Wang X, Hu B. Efficient removal of U(VI) from aqueous solutions using the magnetic biochar derived from the biomass of a bloom-forming cyanobacterium (Microcystis aeruginosa). CHEMOSPHERE 2020; 254:126898. [PMID: 32957293 DOI: 10.1016/j.chemosphere.2020.126898] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/22/2020] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
The utilization of Microcystis biomass is an urgent issue in the mitigation of cyanobacterial bloom. In this study, Microcystis-derived biochar (MB) and Fe3O4-modified biochar (Fe3O4/MB) were fabricated for the U(VI) elimination. The results showed that U(VI) sorption process by either MB or Fe3O4/MB was pH-dependent and ionic strength-independent. The maximum sorption capacity of MB was higher than that of Fe3O4/MB. According to the analysis of X-ray photoelectron spectroscopy, U(VI) sorption on both MB and Fe3O4/MB was mainly ascribed to the surface complexation between U(VI) and oxygen-containing functional groups on the surface of MB. Fe3O4 particles on the surface of MB didn't provide extra active sites for the sorption of U(VI), but it enabled the adsorbent to be magnetically separated. Five consecutive sorption/desorption cycles verified the good reusability of Fe3O4/MB in this study. Therefore, the investigation is not only meaningful for the utilization of nuisance biomass from cyanobacterial blooms, but also provides novel adsorbents for the U(VI) removal from aqueous solutions.
Collapse
Affiliation(s)
- Binliang Wang
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing, 312000, PR China
| | - Yingying Li
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing, 312000, PR China
| | - Junli Zheng
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing, 312000, PR China
| | - Yiwei Hu
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing, 312000, PR China
| | - Xiaojun Wang
- Department of Mathematics, Shaoxing University, Huancheng West Road 508, Shaoxing, 312000, PR China.
| | - Baowei Hu
- School of Life Science, Shaoxing University, Huancheng West Road 508, Shaoxing, 312000, PR China.
| |
Collapse
|
21
|
Shyntum DY, Nkomo NP, Shingange NL, Gricia AR, Bellieny-Rabelo D, Moleleki LN. The Impact of Type VI Secretion System, Bacteriocins and Antibiotics on Bacterial Competition of Pectobacterium carotovorum subsp. brasiliense and the Regulation of Carbapenem Biosynthesis by Iron and the Ferric-Uptake Regulator. Front Microbiol 2019; 10:2379. [PMID: 31681235 PMCID: PMC6813493 DOI: 10.3389/fmicb.2019.02379] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 09/30/2019] [Indexed: 12/17/2022] Open
Abstract
The complexity of plant microbial communities provides a rich model for investigating biochemical and regulatory strategies involved in interbacterial competition. Within these niches, the soft rot Enterobacteriaceae (SRE) represents an emerging group of plant-pathogens causing soft rot/blackleg diseases resulting in economic losses worldwide in a variety of crops. A preliminary screening using next-generation sequencing of 16S rRNA comparatively analyzing healthy and diseased potato tubers, identified several taxa from Proteobacteria to Firmicutes as potential potato endophytes/plant pathogens. Subsequent to this, a range of molecular and computational techniques were used to determine the contribution of antimicrobial factors such as bacteriocins, carbapenem and type VI secretion system (T6SS), found in an aggressive SRE (Pectobacterium carotovorum subsp. brasiliense strain PBR1692 - Pcb1692) against these endophytes/plant pathogens. The results showed growth inhibition of several Proteobacteria by Pcb1692 depends either on carbapenem or pyocin production. Whereas for targeted Firmicutes, only the Pcb1692 pyocin seems to play a role in growth inhibition. Furthermore, production of carbapenem by Pcb1692 was observably dependent on the presence of environmental iron and oxygen. Additionally, upon deletion of fur, slyA and expI regulators, carbapenem production ceased, implying a complex regulatory mechanism involving these three genes. Finally, the results demonstrated that although T6SS confers no relevant advantage during in vitro competition, a significant attenuation in competition by the mutant strain lacking a functional T6SS was observed in planta. IMPORTANCE Soft rot Enterobacteriaceae (SRE) represents important phytopathogens causing soft rot/blackleg diseases in a variety of crops leading to huge economic losses worldwide. These pathogens have been isolated alongside other bacteria from different environments such as potato tubers, stems, roots and from the soil. In these environments, SREs coexist with other bacteria where they have to compete for scarce nutrients and other resources. In this report, we show that Pectobacterium carotovorum subsp. brasiliense strain PBR1692 - Pcb1692, which represents one of the SREs, inhibits growth of several different bacteria by producing different antimicrobial compounds. These antimicrobial compounds can be secreted inside or outside the plant host, allowing Pcb1692 to effectively colonize different types of ecological niches. By analyzing the genome sequences of several SREs, we show that other SREs likely deploy similar antimicrobials to target other bacteria.
Collapse
Affiliation(s)
- Divine Yufetar Shyntum
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Forestry, Agriculture and Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Ntombikayise Precious Nkomo
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Forestry, Agriculture and Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Ntwanano Luann Shingange
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
| | - Alessandro Rino Gricia
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Forestry, Agriculture and Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Daniel Bellieny-Rabelo
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Forestry, Agriculture and Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Lucy Novungayo Moleleki
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Forestry, Agriculture and Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| |
Collapse
|
22
|
Nitrate-Utilizing Microorganisms Resistant to Multiple Metals from the Heavily Contaminated Oak Ridge Reservation. Appl Environ Microbiol 2019; 85:AEM.00896-19. [PMID: 31253673 DOI: 10.1128/aem.00896-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/20/2019] [Indexed: 11/20/2022] Open
Abstract
Contamination of environments with nitrate generated by industrial processes and the use of nitrogen-containing fertilizers is a growing problem worldwide. While nitrate can be removed from contaminated areas by microbial denitrification, nitrate frequently occurs with other contaminants, such as heavy metals, that have the potential to impede the process. Here, nitrate-reducing microorganisms were enriched and isolated from both groundwater and sediments at the Oak Ridge Reservation (ORR) using concentrations of nitrate and metals (Al, Mn, Fe, Co, Ni, Cu, Cd, and U) similar to those observed in a contaminated environment at ORR. Seven new metal-resistant, nitrate-reducing strains were characterized, and their distribution across both noncontaminated and contaminated areas at ORR was examined. While the seven strains have various pH ranges for growth, carbon source preferences, and degrees of resistance to individual and combinations of metals, all were able to reduce nitrate at similar rates both in the presence and absence of the mixture of metals found in the contaminated ORR environment. Four strains were identified in groundwater samples at different ORR locations by exact 16S RNA sequence variant analysis, and all four were found in both noncontaminated and contaminated areas. By using environmentally relevant metal concentrations, we successfully isolated multiple organisms from both ORR noncontaminated and contaminated environments that are capable of reducing nitrate in the presence of extreme mixed-metal contamination.IMPORTANCE Nitrate contamination is a global issue that affects groundwater quality. In some cases, cocontamination of groundwater with nitrate and mixtures of heavy metals could decrease microbially mediated nitrate removal, thereby increasing the duration of nitrate contamination. Here, we used metal and nitrate concentrations that are present in a contaminated site at the Oak Ridge Reservation to isolate seven metal-resistant strains. All were able to reduce nitrate in the presence of high concentrations of a mixture of heavy metals. Four of seven strains were located in pristine as well as contaminated sites at the Oak Ridge Reservation. Further study of these nitrate-reducing strains will uncover mechanisms of resistance to multiple metals that will increase our understanding of the effect of nitrate and metal contamination on groundwater microbial communities.
Collapse
|
23
|
Chai L, Ding C, Li J, Yang Z, Shi Y. Multi-omics response of Pannonibacter phragmitetus BB to hexavalent chromium. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 249:63-73. [PMID: 30878863 DOI: 10.1016/j.envpol.2019.03.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/25/2019] [Accepted: 03/03/2019] [Indexed: 05/27/2023]
Abstract
The release of hexavalent chromium [Cr(VI)] into water bodies poses a major threat to the environment and human health. However, studies of the biological response to Cr(VI) are limited. In this study, a toxic bacterial mechanism of Cr(VI) was investigated using Pannonibacter phragmitetus BB (hereafter BB), which was isolated from chromate slag. The maximum Cr(VI) concentrations with respect to the resistance and reduction by BB are 4000 mg L-1 and 2500 mg L-1, respectively. In the BB genome, more genes responsible for Cr(VI) resistance and reduction are observed compared with other P. phragmitetus strains. A total of 361 proteins were upregulated to respond to Cr(VI) exposure, including enzymes for Cr(VI) uptake, intracellular reduction, ROS detoxification, DNA repair, and Cr(VI) efflux and proteins associated with novel mechanisms involving extracellular reduction mediated by electron transfer, quorum sensing, and chemotaxis. Based on metabolomic analysis, 174 metabolites were identified. Most of the upregulated metabolites are involved in amino acid, glucose, lipid, and energy metabolisms. The results show that Cr(VI) induces metabolite production, while metabolites promote Cr(VI) reduction. Overall, multi-enzyme expression and metabolite production by BB contribute to its high ability to resist/reduce Cr(VI). This study provides details supporting the theory of Cr(VI) reduction and a theoretical basis for the efficient bioremoval of Cr(VI) from the environment.
Collapse
Affiliation(s)
- Liyuan Chai
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; National Engineering Research Center for Heavy Metals Pollution Control and Treatment, 410083, Changsha, China
| | - Chunlian Ding
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China
| | - Jiawei Li
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China
| | - Zhihui Yang
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; National Engineering Research Center for Heavy Metals Pollution Control and Treatment, 410083, Changsha, China
| | - Yan Shi
- Institute of Environmental Science and Engineering, School of Metallurgy and Environment, Central South University, 410083, Changsha, China; National Engineering Research Center for Heavy Metals Pollution Control and Treatment, 410083, Changsha, China.
| |
Collapse
|
24
|
Banerjee S, Misra A, Chaudhury S, Dam B. A Bacillus strain TCL isolated from Jharia coalmine with remarkable stress responses, chromium reduction capability and bioremediation potential. JOURNAL OF HAZARDOUS MATERIALS 2019; 367:215-223. [PMID: 30594722 DOI: 10.1016/j.jhazmat.2018.12.038] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/10/2018] [Accepted: 12/12/2018] [Indexed: 06/09/2023]
Abstract
Microbial reduction of Cr(VI) to Cr(III) can mitigate environmental chromium toxicity. A chromium, cadmium and nickel tolerating strain TCL with 97% 16S rRNA gene sequence homology to Bacillus cereus was isolated from a derelict open-cast, Tasra Coalmine Lake of Jharia, India. It could tolerate up to Cr2000 [2,000 mg L-1 Cr(VI)] and completely reduce Cr200 within 16 h under heterotrophic condition. TCL grown in ≥ Cr500 exhibited multifarious stress responses particularly in its prolonged lag-phase, like cell aggregation, up to two-fold elongation, increased exopolysaccharide production, and stress enzyme activities. These were relieved by increasing inoculum size or nutrient content. Chromium reduction was constitutive, with maximum activities detected in loosely-bound exopolysaccharides and membrane fractions, followed by cytoplasm and spent media. Cr(VI) was efficiently reduced to Cr(III) and >90% was released in spent media. Cells also expressed Cr-induced active efflux pumps. Growing cells or its crude enzyme extracts could efficiently reduce Cr(VI) in diverse temperatures (15-45 °C), pH (5-9); and in presence of other metals (Cd, Cu, Mo, Ni, Pb), oxyanions (SO4-2, NO2-), and metabolic inhibitors (phenol, NaN3, EDTA). Growth and reduction were also detected in nutrient-limited minimal salt media, and contaminated leather industry effluent thereby making TCL a potential candidate for bioremediation.
Collapse
Affiliation(s)
- Sohini Banerjee
- Microbiology Laboratory, Department of Botany (DST-FIST and UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal 731235, India; Department of Environmental Studies, Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal 731235, India
| | - Arijit Misra
- Microbiology Laboratory, Department of Botany (DST-FIST and UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal 731235, India
| | - Shibani Chaudhury
- Department of Environmental Studies, Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal 731235, India
| | - Bomba Dam
- Microbiology Laboratory, Department of Botany (DST-FIST and UGC-DRS Funded), Institute of Science, Visva-Bharati (A Central University), Santiniketan, West Bengal 731235, India.
| |
Collapse
|
25
|
Carlson HK, Price MN, Callaghan M, Aaring A, Chakraborty R, Liu H, Kuehl JV, Arkin AP, Deutschbauer AM. The selective pressures on the microbial community in a metal-contaminated aquifer. ISME JOURNAL 2018; 13:937-949. [PMID: 30523276 PMCID: PMC6461962 DOI: 10.1038/s41396-018-0328-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/12/2018] [Accepted: 11/22/2018] [Indexed: 12/25/2022]
Abstract
In many environments, toxic compounds restrict which microorganisms persist. However, in complex mixtures of inhibitory compounds, it is challenging to determine which specific compounds cause changes in abundance and prevent some microorganisms from growing. We focused on a contaminated aquifer in Oak Ridge, Tennessee, USA that has large gradients of pH and widely varying concentrations of uranium, nitrate, and many other inorganic ions. In the most contaminated wells, the microbial community is enriched in the Rhodanobacter genus. Rhodanobacter abundance is positively correlated with low pH and high concentrations of uranium and 13 other ions and we sought to determine which of these ions are selective pressures that favor the growth of Rhodanobacter over other taxa. Of these ions, low pH and high UO22+, Mn2+, Al3+, Cd2+, Zn2+, Co2+, and Ni2+ are both (a) selectively inhibitory of a Pseudomonas isolate from an uncontaminated well vs. a Rhodanobacter isolate from a contaminated well, and (b) reach toxic concentrations (for the Pseudomonas isolate) in the Rhodanobacter-dominated wells. We used mixtures of ions to simulate the groundwater conditions in the most contaminated wells and verified that few isolates aside from Rhodanobacter can tolerate these eight ions. These results clarify which ions are likely causal factors that impact the microbial community at this field site and are not merely correlated with taxonomic shifts. Furthermore, our general high-throughput approach can be applied to other environments, isolates, and conditions to systematically help identify selective pressures on microbial communities.
Collapse
Affiliation(s)
- Hans K Carlson
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
| | - Morgan N Price
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Mark Callaghan
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Alex Aaring
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Romy Chakraborty
- Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Hualan Liu
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Jennifer V Kuehl
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Adam P Arkin
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.,Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
| | - Adam M Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA. .,Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA.
| |
Collapse
|
26
|
Otwell AE, López García de Lomana A, Gibbons SM, Orellana MV, Baliga NS. Systems biology approaches towards predictive microbial ecology. Environ Microbiol 2018; 20:4197-4209. [DOI: 10.1111/1462-2920.14378] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 08/14/2018] [Indexed: 01/17/2023]
Affiliation(s)
| | | | - Sean M. Gibbons
- Institute for Systems Biology Seattle WA USA
- eScience Institute, University of Washington Seattle WA USA
- Molecular and Cellular Biology Program University of Washington Seattle WA USA
| | - Mónica V. Orellana
- Institute for Systems Biology Seattle WA USA
- Polar Science Center Applied Physics Lab, University of Washington Seattle WA
| | - Nitin S. Baliga
- Institute for Systems Biology Seattle WA USA
- Molecular and Cellular Biology Program University of Washington Seattle WA USA
- Departments of Biology and Microbiology University of Washington Seattle WA USA
- Lawrence Berkeley National Lab Berkeley CA USA
| |
Collapse
|
27
|
Gan M, Li J, Sun S, Ding J, Zhu J, Liu X, Qiu G. Synergistic effect between sulfide mineral and acidophilic bacteria significantly promoted Cr(VI) reduction. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2018; 219:84-94. [PMID: 29730593 DOI: 10.1016/j.jenvman.2018.04.118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 04/19/2018] [Accepted: 04/30/2018] [Indexed: 06/08/2023]
Abstract
Natural pyrite was an economical choice for efficient Cr(VI) remediation, while its deep utilization was inhibited due to the passivation effect. In this study, pyrite passivation/dissolution and active sites regeneration mechanism under the activity of acidophilic bacteria with different energy metabolism characteristic in Cr(VI) reduction have been investigated. The reduction capacity was in the order of Acidithiobacillus thiooxidans, Acidithiobacillus ferrooxidans(S), Acidithiobacillus ferrooxidans(Fe), Leptospirillum ferrooxidans and chemical control. The maximal reduction efficiency was achieved in A. thiooxidans system, which is 4.5 times higher than the L. ferrooxidans system. In chemical system, sulfur and Fe(III)/Cr(III)-oxyhydroxysulphate accumulation would result in pyrite passivation. A. thiooxidans attached on pyrite surface and exerted synergistic effect on pyrite corrosion coupled with Cr(VI). Sulfur oxidation promoted proton regeneration, pyrite lattice Fe(II) dissolution and active sites regeneration, which were beneficial to sustainable Cr(VI) reduction. Secondary iron mineral formation on pyrite was accelerated with the iron oxidation bacteria activity increasing. Excessive oxidation to surface sites Fe(II) and the accumulation of S0/Sn2- led to the passivation effect in L. ferrooxidans system. Cr(VI) acquired electron from Fe(II) and disulfide and resulted in the bond break between them. The combined effect of specific sulfur oxidizing bacteria activity and Cr(VI) oxidation efficient promoted pyrite dissolution and active sites regeneration. The interaction between acidophilic bacteria and pyrite significantly enhanced Cr(VI) reduction efficiency.
Collapse
Affiliation(s)
- Min Gan
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Jiayu Li
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Shengjie Sun
- Advanced Water Management Centre, Building 60, Research Road, The University of Queensland, St Lucia, Brisbane, QLD 4072, Australia
| | - Jijuan Ding
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Jianyu Zhu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China.
| | - Xinxing Liu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| | - Guanzhou Qiu
- School of Minerals Processing and Bioengineering, Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, China
| |
Collapse
|