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Huang X, Song W, Yang Z, Wu Z, Chen L, Liang Q, Li J, Tu C, Zheng G, Zhou W, Zhang X. The important role of EPS in mediated biosynthesis of CdS QDs: Comparative study of EPS-intact and EPS-free. JOURNAL OF HAZARDOUS MATERIALS 2024; 474:134760. [PMID: 38820746 DOI: 10.1016/j.jhazmat.2024.134760] [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: 04/21/2024] [Revised: 05/11/2024] [Accepted: 05/28/2024] [Indexed: 06/02/2024]
Abstract
In this study, we investigated the adsorption of Cd(II) and the biosynthesis of CdS quantum dots (QDs) mediated by cells of sulfate-reducing bacteria before and after the removal of EPS to determine whether EPS or the cell wall plays a major role. Potentiometric titration revealed that the concentration of proton-active binding sites on cells with EPS (EPS-intact) was notably higher than that on cells without EPS (EPS-free) and that the sites were predominantly carboxyl, phosphoryl, hydroxyl, and amine groups. The protein content in EPS-intact cells was higher, and thus the Cd(II) adsorption capacity was stronger. The CdS QDs biosynthesized using EPS-intact possessed better properties, including uniform size distribution, good crystallinity, small particle size, high fluorescence, and strong antimicrobial activity, and the yields were significantly higher than those of EPS-free by a factor of about 1.5-3.7. Further studies revealed that alkaline amino acids in EPS play a major role and serve as templates in the biosynthesis of QDs, whereas they were rarely detected in the cell wall. This study emphasizes the important role of EPS in the bacterial binding of metals and efficient recycling of hazardous waste in water.
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Affiliation(s)
- Xiangwu Huang
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Weifeng Song
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China.
| | - Zuoyi Yang
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China.
| | - Zhixin Wu
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Liyao Chen
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Qiantong Liang
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Jinfu Li
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Chuanying Tu
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Guangwen Zheng
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Wenbin Zhou
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Xiangdan Zhang
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
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Huang X, Yang Z, Dai W, Song W, Gan Y, Lian Z, Zhou W, Wu Z, Chen L, Bai X. Mediated biosynthesis of CdS QDs by EPS from Desulfovibrio desulfuricans sub sp. under carbon source-induced reinforcement. JOURNAL OF HAZARDOUS MATERIALS 2023; 459:132146. [PMID: 37499495 DOI: 10.1016/j.jhazmat.2023.132146] [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: 05/30/2023] [Revised: 07/18/2023] [Accepted: 07/23/2023] [Indexed: 07/29/2023]
Abstract
This paper describes a unique molecular mechanism for the EPS-mediated synthesis of CdS QDs by sulfate-reducing bacteria (SRB) under carbon source-induced reinforcement. Under the induced by carbon sources (HCOONa, CH3COONa and C6H12O6), there was a significant increase in EPS production of SRB, particularly in protein, and the capacity of Cd(II) adsorption was further enhanced. CdS QDs were extracellularly synthesized by adding S2- after Cd(II) adsorption. The results showed that CdS QDs were wrapped or adhered by EPS, and the most significant increase in Arg and Lys among basic amino acids in EPS after HCOONa-induced was 133.34% and 63.89%, respectively. This may serve as a biological template for QD synthesis, producing protein gels with a large number of microcavities and controlling the nucleation of CdS QDs. The highest yield of HCOONa-CdS was achieved after induction, with 23.59 g/g biomass per unit strain, which was 447.34% higher than that before induction and was at a high level in previous studies. The synthesized CdS QDs were uniform in size distribution and had higher luminescence activity and a larger specific surface area than those synthesized by the chemical synthesis route, provides a new idea for EPS treatment of heavy metal wastewater and metal biorecovery.
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Affiliation(s)
- Xiangwu Huang
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Zuoyi Yang
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Wencan Dai
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China.
| | - Weifeng Song
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China.
| | - Yu Gan
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Zeyang Lian
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Wenbin Zhou
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Zhixin Wu
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Liyao Chen
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
| | - Xiaoyan Bai
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, Guangdong 510006, China
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Yang L, Chen Z, Zhang Y, Lu F, Liu Y, Cao M, He N. Hyperproduction of extracellular polymeric substance in Pseudomonas fluorescens for efficient chromium (VI) absorption. BIORESOUR BIOPROCESS 2023; 10:17. [PMID: 38647825 PMCID: PMC10992911 DOI: 10.1186/s40643-023-00638-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 02/13/2023] [Indexed: 04/25/2024] Open
Abstract
A novel extracellular polymeric substance (EPS) with flocculating activity produced by Pseudomonas fluorescein isolated from soil was studied in this paper. Firstly, atmospheric and room temperature plasma (ARTP) was applied to get a mutant of P. fluorescein with higher EPS production. A mutant T4-2 exhibited a 106.48% increase in flocculating activity compared to the original strain. The maximum EPS yield from T4-2 was enhanced up to 6.42 g/L, nearly 10 times higher than the original strain on a 3.6-L bioreactor with optimized fermentation conditions. Moreover, the flocculating activity of the mutant reached 3023.4 U/mL, 10.96-fold higher than that of T4. Further identification showed that EPS from mutant T4-2 was mainly composed of polysaccharide (76.67%) and protein (15.8%) with a molecular weight of 1.17 × 105 Da. The EPS showed excellent adsorption capacities of 80.13 mg/g for chromium (VI), which was much higher than many reported adsorbents such as chitosan and cellulose. The adsorption results were described by Langmuir isotherm and pseudo-second-order kinetic model. The thermodynamic parameters (ΔG0, ΔH0 and ΔS0) revealed that the adsorption process was spontaneous and exothermic. Adsorption mechanisms were speculated to be electrostatic interaction, reduction, and chelation.
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Affiliation(s)
- Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Zhen Chen
- College of Life Science, Xinyang Normal University, Xinyang, 464000, People's Republic of China
| | - Ying Zhang
- Shandong Institute of Commerce and Technology, Jinan, 251000, People's Republic of China
| | - Fuping Lu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China
| | - Yihan Liu
- Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education, Tianjin Key Laboratory of Industrial Microbiology, The College of Biotechnology, Tianjin University of Science and Technology, Tianjin, 300457, People's Republic of China.
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, People's Republic of China.
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, 361005, People's Republic of China.
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4
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Hasani Zadeh P, Fermoso FG, Collins G, Serrano A, Mills S, Abram F. Impacts of metal stress on extracellular microbial products, and potential for selective metal recovery. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 252:114604. [PMID: 36758509 DOI: 10.1016/j.ecoenv.2023.114604] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Harnessing microbial capabilities for metal recovery from secondary waste sources is an eco-friendly and sustainable approach for the management of metal-containing wastes. Soluble microbial products (SMP) and extracellular polymeric substances (EPS) are the two main groups of extracellular compounds produced by microorganisms in response to metal stress that are of great importance for remediation and recovery of metals. These include various high-, and low, molecular weight components, which serve various functional and structural roles. These compounds often contain functional groups with metal binding potential that can attenuate metal stress by sequestering metal ions, making them less bioavailable. Microorganisms can regulate the content and composition of EPS and SMP in response to metal stress in order to increase the compounds specificity and capacity for metal binding. Thus, EPS and SMP represent ideal candidates for developing technologies for selective metal recovery from complex wastes. To discover highly metal-sorptive compounds with specific metal binding affinity for metal recovery applications, it is necessary to investigate the metal binding affinity of these compounds, especially under metal stressed conditions. In this review we critically reviewed microbial EPS and SMP production as a response to metal stress with a particular emphasis on the metal binding properties of these compounds and their role in altering metal bioavailability. Furthermore, for the first time, we compiled the available data on potential application of these compounds for selective metal recovery from waste streams.
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Affiliation(s)
- Parvin Hasani Zadeh
- Bioprocesses for the Circular Economy Group, Instituto de la Grasa, Spanish National Research Council (CSIC), Seville, Spain; Microbiology, School of Biological and Chemical Sciences, National University of Ireland Galway, Galway, Ireland.
| | - Fernando G Fermoso
- Bioprocesses for the Circular Economy Group, Instituto de la Grasa, Spanish National Research Council (CSIC), Seville, Spain
| | - Gavin Collins
- Microbiology, School of Biological and Chemical Sciences, National University of Ireland Galway, Galway, Ireland
| | - Antonio Serrano
- Institute of Water Research, University of Granada, Granada 18071, Spain; Department of Microbiology, Pharmacy Faculty, University of Granada, Campus de Cartuja s/n, Granada 18071, Spain
| | - Simon Mills
- Microbiology, School of Biological and Chemical Sciences, National University of Ireland Galway, Galway, Ireland
| | - Florence Abram
- Microbiology, School of Biological and Chemical Sciences, National University of Ireland Galway, Galway, Ireland
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5
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Chen Z, Huang Z, Liu H, Wang H, Wei Z. Pb 0 flue gas biosorption in denitrifying MBfR: Characteristics and binding ability of extracellular polymeric substances. CHEMOSPHERE 2023; 314:137703. [PMID: 36587914 DOI: 10.1016/j.chemosphere.2022.137703] [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: 06/10/2022] [Revised: 12/08/2022] [Accepted: 12/29/2022] [Indexed: 06/17/2023]
Abstract
Pb0 in flue gas which is ubiquitous in the environment, poses a certain threat to human and ecology, but the study on EPS-dependent stabilization of lead to remove Pb0 from flue gas remains insufficient. In this investigation, the characteristics and heavy metals-binding ability of four EPS fractions were evaluated. The EPS were extracted from denitrifying membrane biofilm reactor (MBfR) and divided into slime EPS (S-EPS), loosely-bound EPS (LB-EPS), tightly-bound EPS (TB-EPS) and EPS in circulating flow (Y-EPS). The S, LB, TB-EPS related to Pb stabilization on biofilm need more attention. Compared to Pb-S-EPS (0.013 mg g-1) and Pb-LB-EPS (0.13 mg g-1), the Pb-TB-EPS (0.26 mg g-1) was mainly stable form of vapor Pb0, since TB-EPS's higher content (30.67-82.44 mg g-1 VSS), proteins (13.47-36.32 mg g-1 VSS) and polysaccharides (9.37-32.48 mg g-1 VSS) concentration. Particularly, proteins related ligands were more effective in S, LB, TB-EPS dependent adsorption of Pb, complexing with hydrophobic acid ligands further strengthened in TB-EPS adsorption. The Pb-EPS complex formed via binding with functional groups (such as O-H, N-H, C-H and CC) on EPS, also facilitated by loose structure of proteins. This study enlightens the researchers on the bio-treatment and EPS-dependent biosorption of Pb0 in flue gas in denitrifying MBfR.
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Affiliation(s)
- Zhuoyao Chen
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, China
| | - Zhenshan Huang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, China
| | - Haixu Liu
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, China
| | - Huiying Wang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, China
| | - Zaishan Wei
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, Guangzhou, 510006, China.
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Fan K, Xu X, Xu F, Shi J, Sun K, Fedorova I, Ren N, Lee DJ, Chen C. A novel intra- and extracellular distribution pattern of elemental sulfur in Pseudomonas sp. C27-driven denitrifying sulfide removal process. ENVIRONMENTAL RESEARCH 2022; 213:113674. [PMID: 35700768 DOI: 10.1016/j.envres.2022.113674] [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: 05/16/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Pseudomonas sp. C27 can achieve the conversion of toxic sulfide to economical elemental sulfur (S0) with various electron acceptors. In this study the distribution pattern of S0 produced by C27 in denitrifying sulfide removal (DSR) process was explored. The SEM observation identified that the particle size of the biogenic S0 was at micron level. Strikingly, a novel distribution pattern of S0 was revealed that the produced S0 was not directly secreted extracellularly, but be stored temporarily in the cell interior. Pyrolysis at 65 °C for 20 min were recommended prior to S0 recovery, which could maximize the separation of extracellular polymeric substances (EPS) from C27. Furthermore, the effects of N/S molar ratio, initial sulfide concentration, and micro-oxygen condition were investigated to improve the production of S0 by C27. The highest S0 production was obtained at S/N of 3 and anaerobic condition seemed to favor the S0 production by C27. This study would provide a theoretical support for highly efficient sulfide removal as well as S0 recovery in sulfide-laden wastewater treatment.
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Affiliation(s)
- Kaili Fan
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Xijun Xu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Fan Xu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Jia Shi
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Kai Sun
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Irina Fedorova
- Department of Geoecology and Natural Resource Management, Saint Petersburg State University, Institute of Earth Science, Russia
| | - Nanqi Ren
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China
| | - Duu-Jong Lee
- Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Chuan Chen
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, Heilongjiang Province, 150090, China.
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Chen X, Lin H, Dong Y, Li B, Yin T, Liu C. Simultaneous high-efficiency removal of sulfamethoxazole and zinc (II) from livestock and poultry breeding wastewater by a novel dual-functional bacterium, Bacillus sp. SDB4. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:6237-6250. [PMID: 34448142 DOI: 10.1007/s11356-021-15804-3] [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: 04/24/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
The complex mixtures of antibiotics and heavy metals are commonly existed in livestock and poultry breeding wastewater. Effective and simultaneous removal of these toxic compounds by microorganisms, especially single strains, remains a considerable challenge. In this study, a novel functional strain SDB4, isolated from duck manure and identified as Bacillus sp., has been shown to possess high removal capabilities for both sulfamethoxazole (SMX) and Zn2+. The maximum removal efficiency achieved 73.97% for SMX and 84.06% for Zn2+ within 48 h in the single pollution system. It has great potential for eliminating SMX along with Zn2+, 78.45% of SMX and 52.91% of Zn2+ were removed in the 20 mg·L-1 SMX and 100 mg·L-1 Zn2+ binary system. Furthermore, the SMX-biotransformation capability of SDB4 was enhanced at low concentrations of Zn2+ (below 100 mg·L-1). The SMX biotransformation and Zn2+ adsorption data fitted well with the pseudo-first-order kinetic model, indicating that the two pollutants were in accordance with the same removal rule. N4-acetyl-SMX was identified as the main stable transformation product during SMX removal. FTIR analyses revealed that OH, NH2, C=O, C-N/N-H, and C-O-C played major roles in the adsorption of Zn2+. Our study of the dually functioning strain SDB4 provides a potential application for the simultaneous biological removal of antibiotics and heavy metals.
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Affiliation(s)
- Xi Chen
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
- Beijing Key Laboratory on Resource-Oriented Treatment of Industrial Pollutants, Beijing, 100083, China
| | - Hai Lin
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
- Beijing Key Laboratory on Resource-Oriented Treatment of Industrial Pollutants, Beijing, 100083, China.
| | - Yingbo Dong
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
- Beijing Key Laboratory on Resource-Oriented Treatment of Industrial Pollutants, Beijing, 100083, China.
| | - Bing Li
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
- Beijing Key Laboratory on Resource-Oriented Treatment of Industrial Pollutants, Beijing, 100083, China
| | - Tingting Yin
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
- Beijing Key Laboratory on Resource-Oriented Treatment of Industrial Pollutants, Beijing, 100083, China
| | - Chenjing Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
- Beijing Key Laboratory on Resource-Oriented Treatment of Industrial Pollutants, Beijing, 100083, China
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Li C, Yu Y, Fang A, Feng D, Du M, Tang A, Chen S, Li A. Insight into biosorption of heavy metals by extracellular polymer substances and the improvement of the efficacy: a review. Lett Appl Microbiol 2021; 75:1064-1073. [PMID: 34562275 DOI: 10.1111/lam.13563] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 08/26/2021] [Accepted: 09/01/2021] [Indexed: 01/21/2023]
Abstract
Heavy metals are continuously released into aquatic environments in which they accumulate. This phenomenon endangers public health because heavy metals accumulate along the food chain. However, conventional remediation methods are inefficient, expensive and yield toxic intermediate products, which adversely affect the environment. The discovery of green bio-adsorbents such as microbial extracellular polymer substance (EPS) has quickly attracted considerable worldwide attention because of their low cost, high removal efficiency of heavy metals and industrial availability. Hence, this review considers the sources, hazards and treatment methods of heavy metals pollution, particularly the biosorption mechanism of EPS to heavy metals and the influencing factors of the bio-adsorption process, which are significant in the efficient removal of heavy metals-containing wastewater treatment. This review also focuses on strengthening the process of EPS adsorption of heavy metals, which can further contribute to heavy metals removal. Finally, it has been proposed that improving the yield, stability, selectivity and recoverability of EPS is the key direction of further research.
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Affiliation(s)
- C Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, People's Republic of China
| | - Y Yu
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, People's Republic of China
| | - A Fang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, People's Republic of China
| | - D Feng
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, People's Republic of China
| | - M Du
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, People's Republic of China
| | - A Tang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, People's Republic of China
| | - S Chen
- School of Municipal and Environmental Engineering, Jilin University of Architecture and Technology, Changchun, People's Republic of China
| | - A Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, People's Republic of China.,School of Municipal and Environmental Engineering, Jilin University of Architecture and Technology, Changchun, People's Republic of China
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9
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Fluorescent Characteristics and Metal Binding Properties of Different Molecular Weight Fractions in Stratified Extracellular Polymeric Substances of Activated Sludge. SEPARATIONS 2021. [DOI: 10.3390/separations8080120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The combination of heavy metals and extracellular polymeric substances (EPSs) affects the distribution of heavy metals in microbial aggregates, soil, and aquatic systems. This paper aimed to explore the binding mechanisms of EPSs of different molecular weights in activated sludge with heavy metals. We extracted the stratification components of activated sludge EPSs and divided the components into five fractions of different molecular weight ranges. In the three-dimensional fluorescence analysis of each fraction, the EPSs of activated sludge had two peaks, peak A (representing low-excitation tryptophan) and peak B (representing high-excitation tryptophan), and static quenching was the main reason for the fluorescence quenching between the compounds attributable to peak A in activated sludge EPSs and Pb2+ and Cu2+. Further exploration suggested that the EPSs of activated sludge interacted with Cd2+, Pb2+, Cu2+, and Zn2+ to form new substances. The quenching effect of the EPSs with the highest molecular weight (100 kDa–0.7 μm) was more significant, and the binding ability was more stable. This study implies that the application of EPSs from activated sludge is promising. While effectively binding heavy metals, it can also reduce the volume of the excess activated sludge.
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Li Q, Song W, Sun M, Li J, Yu Z. Response of Bacillus vallismortis sp. EPS to exogenous sulfur stress/ induction and its adsorption performance on Cu(II). CHEMOSPHERE 2020; 251:126343. [PMID: 32155492 DOI: 10.1016/j.chemosphere.2020.126343] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 02/01/2020] [Accepted: 02/24/2020] [Indexed: 05/27/2023]
Abstract
The chemical composition of EPS (Extracellular Polymeric Substances) produced by Bacillus vallismortis sp. and its adsorption performance on typical heavy metal were studied under Na2S stress/induction at different concentrations. Its structure was characterized by three-dimensional fluorescence spectrogram (3D-EEM), infrared spectrum (FTIR) and X-ray photoelectron spectroscopy (XPS). The results showed that, when the Na2S stress/induction intensity was 20 mg/L, the protein concentration was nearly doubled compared with Control-EPS (EPS produced by Bacillus vallismortis sp. without exogenous sulfur stress); furthermore, the 3D-EEM results also demonstrated that there was an increase in the protein content, with the -SH content reaching 154.36 μmol/L, which was 48.2% higher than before stress (104.15 μmol/L). Under this condition, S-EPS (EPS produced by Bacillus vallismortis sp. stressed by exogenous sulfur) exhibited the best adsorption effect on Cu(II), with the theoretical maximum adsorption capacity reaching 1428.57 mg/g EPS. FTIR and XPS analyses revealed that the -SH, CO, N-H played a major role in the adsorption of Cu(II); among those, -SH played a key role. Moreover, the adsorption capacity of Cu(II) by S-EPS was correlated with the content of sulfhydryl protein; indeed, the exogenous sulfur stress/induction can effectively regulate the chemical composition of EPS and improve its adsorption performance, which can be crucial in the prevention and control of heavy metal pollution.
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Affiliation(s)
- Qiuhua Li
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, 510006, China
| | - Weifeng Song
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, 510006, China.
| | - Mengge Sun
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, 510006, China
| | - Jiayao Li
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, 510006, China
| | - Zefeng Yu
- School of Environmental Science and Engineering of Guangdong University of Technology, Guangzhou, 510006, China
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