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Huang L, Jin Y, Zhou D, Liu L, Huang S, Zhao Y, Chen Y. A Review of the Role of Extracellular Polymeric Substances (EPS) in Wastewater Treatment Systems. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:12191. [PMID: 36231490 PMCID: PMC9566195 DOI: 10.3390/ijerph191912191] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/18/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
A review of the characterization and functions of extracellular polymeric substances (EPS) of microbial aggregates in biological wastewater treatment systems is presented in this paper. EPS represent the complex high-molecular-weight mixture of polymers excreted by microorganisms generated from cell lysis as well as adsorbed inorganic and organic matter from wastewater. EPS exhibit a three-dimensional, gel-like, highly hydrated matrix that facilitates microbial attachment, embedding, and immobilization. EPS play multiple roles in containments removal, and the main components of EPS crucially influence the properties of microbial aggregates, such as adsorption ability, stability, and formation capacity. Moreover, EPS are important to sludge bioflocculation, settleability, and dewatering properties and could be used as carbon and energy sources in wastewater treatment. However, due to the complex structure of EPS, related knowledge is incomplete, and further research is necessary to understand fully the precise roles in biological treatment processes.
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Affiliation(s)
- Lei Huang
- Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, China
| | - Yinie Jin
- Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Danheng Zhou
- Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Linxin Liu
- Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Shikun Huang
- Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yaqi Zhao
- Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
| | - Yucheng Chen
- Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment (Ministry of Education), College of Resources and Environment, Southwest University, Chongqing 400715, China
- Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, China
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Sakr EAE, Khater DZ, El-Khatib KM. Anodic and cathodic biofilms coupled with electricity generation in single-chamber microbial fuel cell using activated sludge. Bioprocess Biosyst Eng 2021; 44:2627-2643. [PMID: 34498106 DOI: 10.1007/s00449-021-02632-5] [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: 05/27/2021] [Accepted: 08/29/2021] [Indexed: 10/20/2022]
Abstract
Microbial fuel cell (MFC) is used to remove organic pollutants while generating electricity. Biocathode plays as an efficient electrocatalyst for accelerating the Oxidation Reduction Reaction (ORR) of oxygen in MFC. This study integrated biocathode into a single-chamber microbial fuel cell (BSCMFC) to produce electricity from an organic substrate using aerobic activated sludge to gain more insights into anodic and cathodic biofilms. The maximum power density, current density, chemical oxygen demand (COD) removal, and coulombic efficiency were 0.593 W m-3, 2.6 A m-3, 83 ± 8.4%, and 22 ± 2.5%, respectively. Extracellular polymeric substances (EPS) produced by biofilm from the biocathode were higher than the bioanode. Infrared spectroscopy and Scanning Electron Microscope (SEM) examined confirmed the presence of biofilm by the adhesion on electrodes. The dominant phyla in bioanode were Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria, while the dominant phylum in the biocathode was Proteobacteria. Therefore, this study demonstrates the applicable use of BSCMFC for bioelectricity generation and pollution control.
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Affiliation(s)
- Ebtehag A E Sakr
- Botany Department, Faculty of Women for Arts, Science and Education, Ain Shams University, Cairo, Egypt.
| | - Dena Z Khater
- Chemical Engineering and Pilot Plant Department, National Research Centre (NRC), El Buhouth St., 12622-Dokki, Cairo, Egypt
| | - K M El-Khatib
- Chemical Engineering and Pilot Plant Department, National Research Centre (NRC), El Buhouth St., 12622-Dokki, Cairo, Egypt
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Chen Z, Meng Y, Sheng B, Zhou Z, Jin C, Meng F. Linking Exoproteome Function and Structure to Anammox Biofilm Development. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:1490-1500. [PMID: 30615829 DOI: 10.1021/acs.est.8b04397] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Extracellular proteins are of paramount importance in the cell-cell interactions of anammox biofilms. However, the inherent aggregation mechanisms of anammox have largely remained elusive. Herein, using a quartz sand extraction protocol and follow-up iTRAQ-based quantitative proteomics, we identified 367 extracellular proteins from initial colonizers, mature biofilm, and detached biofilm. The extracellular proteins were mainly membrane-associated. Most of the recovered proteins (226, 72.5%) originated from the phylum Planctomycetes. In summary, 215 and 190 of the 367 proteins recovered were up- and/or downregulated at least 1.2-fold during the biofilm formation and detachment periods, respectively. These differentially expressed proteins were dominantly involved in metal ion binding, which was regarded as strong evidence for their abilities to enhance ionic bridges in extracellular polymeric substances (EPS). Scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX) analysis of the biofilms further showed substantial levels of calcium and iron minerals. Critically, representative Sec-dependent secretory proteins affiliated with coccoid Planctomycetes, rod-shaped Proteobacteria, and filamentous Chloroflexi (11, 4, and 2 with differential expression, respectively) were found to have typical and abundant inner β-sheet structures, wherein hydrophobic moieties can promote anammox aggregation. Overall, these findings highlight links between differentially expressed protein functions and morphologic traits of anammox consortia during biofilm development.
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Affiliation(s)
- Zijian Chen
- School of Environmental Science and Engineering , Sun Yat-sen University , Guangzhou 510275 , P.R. China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) , Guangzhou 510275 , P.R. China
| | - Yabing Meng
- School of Environmental Science and Engineering , Sun Yat-sen University , Guangzhou 510275 , P.R. China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) , Guangzhou 510275 , P.R. China
| | - Binbin Sheng
- School of Environmental Science and Engineering , Sun Yat-sen University , Guangzhou 510275 , P.R. China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) , Guangzhou 510275 , P.R. China
| | - Zhongbo Zhou
- School of Environmental Science and Engineering , Sun Yat-sen University , Guangzhou 510275 , P.R. China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) , Guangzhou 510275 , P.R. China
| | - Chao Jin
- School of Environmental Science and Engineering , Sun Yat-sen University , Guangzhou 510275 , P.R. China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) , Guangzhou 510275 , P.R. China
| | - Fangang Meng
- School of Environmental Science and Engineering , Sun Yat-sen University , Guangzhou 510275 , P.R. China
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology (Sun Yat-sen University) , Guangzhou 510275 , P.R. China
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Tian X, Shen Z, Han Z, Zhou Y. The effect of extracellular polymeric substances on exogenous highly toxic compounds in biological wastewater treatment: An overview. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2018.11.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ding Z, Bourven I, van Hullebusch ED, Panico A, Pirozzi F, Esposito G, Guibaud G. Quantitative and qualitative characterization of extracellular polymeric substances from Anammox enrichment. J Taiwan Inst Chem Eng 2017. [DOI: 10.1016/j.jtice.2017.09.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Wang Z, Gao M, Wei J, Ma K, Pei J, Zhang J, Zhou Y, Yang Y, Yu S. Long-term effects of salinity on extracellular polymeric substances, microbial activity and microbial community from biofilm and suspended sludge in an anoxic-aerobic sequencing batch biofilm reactor. J Taiwan Inst Chem Eng 2016. [DOI: 10.1016/j.jtice.2016.09.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Wang Z, Gao M, Wei J, Ma K, Zhang J, Yang Y, Yu S. Extracellular polymeric substances, microbial activity and microbial community of biofilm and suspended sludge at different divalent cadmium concentrations. BIORESOURCE TECHNOLOGY 2016; 205:213-221. [PMID: 26829529 DOI: 10.1016/j.biortech.2016.01.067] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 01/06/2016] [Accepted: 01/08/2016] [Indexed: 06/05/2023]
Abstract
The differences between biofilm and suspended sludge (S-sludge) in extracellular polymeric substances (EPS), microbial activity, and microbial community in an anoxic-aerobic sequencing batch biofilm reactor (SBBR) at different concentrations of divalent cadmium (Cd(II)) were investigated. As the increase of Cd(II) concentration from 0 to 50mgL(-1), the specific ammonium oxidation rate (SAOR), specific nitrite oxidation rate (SNOR), and specific nitrate reduction rate (SNRR) of biofilm decreased from 4.85, 5.22 and 45mgNg(-1) VSSh(-1) to 1.54, 2.38 and 26mgNg(-1)VSSh(-1), respectively, and the SAOR, SNOR and SNRR of S-sludge decreased from 4.80, 5.02 and 34mgNg(-1)VSSh(-1) to 1.46, 2.20 and 17mgNg(-1)VSSh(-1), respectively. Biofilm had higher protein (PN) content in EPS than S-sludge. Contrast to S-sludge, biofilm could provide Nitrobacter vulgaris, beta proteobacterium INBAF015, and Pseudoxanthomonas mexicana with the favorable conditions of growth and reproduction.
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Affiliation(s)
- Zichao Wang
- College of Environment and Chemical Engineering, Dalian University, Dalian, China; Key Lab of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, China.
| | - Mengchun Gao
- Key Lab of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao, China
| | - Junfeng Wei
- College of Environment and Chemical Engineering, Dalian University, Dalian, China
| | - Kedong Ma
- College of Environment and Chemical Engineering, Dalian University, Dalian, China
| | - Jing Zhang
- College of Environment and Chemical Engineering, Dalian University, Dalian, China
| | - Yusuo Yang
- College of Environment and Chemical Engineering, Dalian University, Dalian, China
| | - Shuping Yu
- College of Environment and Chemical Engineering, Dalian University, Dalian, China
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Jachlewski S, Jachlewski WD, Linne U, Bräsen C, Wingender J, Siebers B. Isolation of Extracellular Polymeric Substances from Biofilms of the Thermoacidophilic Archaeon Sulfolobus acidocaldarius. Front Bioeng Biotechnol 2015; 3:123. [PMID: 26380258 PMCID: PMC4550784 DOI: 10.3389/fbioe.2015.00123] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 08/10/2015] [Indexed: 11/13/2022] Open
Abstract
Extracellular polymeric substances (EPS) are the major structural and functional components of microbial biofilms. The aim of this study was to establish a method for EPS isolation from biofilms of the thermoacidophilic archaeon, Sulfolobus acidocaldarius, as a basis for EPS analysis. Biofilms of S. acidocaldarius were cultivated on the surface of gellan gum-solidified Brock medium at 78°C for 4 days. Five EPS extraction methods were compared, including shaking of biofilm suspensions in phosphate buffer, cation-exchange resin (CER) extraction, and stirring with addition of EDTA, crown ether, or NaOH. With respect to EPS yield, impact on cell viability, and compatibility with subsequent biochemical analysis, the CER extraction method was found to be the best suited isolation procedure resulting in the detection of carbohydrates and proteins as the major constituents and DNA as a minor component of the EPS. Culturability of CER-treated cells was not impaired. Analysis of the extracellular proteome using two-dimensional gel electrophoresis resulted in the detection of several hundreds of protein spots, mainly with molecular masses of 25–116 kDa and pI values of 5–8. Identification of proteins suggested a cytoplasmic origin for many of these proteins, possibly released via membrane vesicles or biofilm-inherent cell lysis during biofilm maturation. Functional analysis of EPS proteins, using fluorogenic substrates as well as zymography, demonstrated the activity of diverse enzyme classes, such as proteases, lipases, esterases, phosphatases, and glucosidases. In conclusion, the CER extraction method, as previously applied to bacterial biofilms, also represents a suitable method for isolation of water soluble EPS from the archaeal biofilms of S. acidocaldarius, allowing the investigation of composition and function of EPS components in these types of biofilms.
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Affiliation(s)
- Silke Jachlewski
- Molecular Enzyme Technology and Biochemistry (MEB), Biofilm Centre, Centre for Water and Environmental Research (CWE), University Duisburg-Essen , Essen , Germany
| | - Witold D Jachlewski
- Aquatic Microbiology, Biofilm Centre, Centre for Water and Environmental Research (CWE), University Duisburg-Essen , Essen , Germany
| | - Uwe Linne
- Core Facility for Mass Spectrometry and Elemental Analysis, Department of Chemistry and SYNMIKRO, Philipps-University of Marburg , Marburg , Germany
| | - Christopher Bräsen
- Molecular Enzyme Technology and Biochemistry (MEB), Biofilm Centre, Centre for Water and Environmental Research (CWE), University Duisburg-Essen , Essen , Germany
| | - Jost Wingender
- Aquatic Microbiology, Biofilm Centre, Centre for Water and Environmental Research (CWE), University Duisburg-Essen , Essen , Germany
| | - Bettina Siebers
- Molecular Enzyme Technology and Biochemistry (MEB), Biofilm Centre, Centre for Water and Environmental Research (CWE), University Duisburg-Essen , Essen , Germany
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Zhang P, Guo JS, Shen Y, Yan P, Chen YP, Wang H, Yang JX, Fang F, Li C. Microbial communities, extracellular proteomics and polysaccharides: A comparative investigation on biofilm and suspended sludge. BIORESOURCE TECHNOLOGY 2015; 190:21-28. [PMID: 25919933 DOI: 10.1016/j.biortech.2015.04.058] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 04/14/2015] [Accepted: 04/16/2015] [Indexed: 06/04/2023]
Abstract
Biofilm and suspended sludge (S-sludge) floc exhibit distinct physicochemical properties and process performances in an integrated fixed-film and suspended growth sequencing batch reactor. However, the mechanisms of governing these differences between the two aggregates were unknown. Current work evaluated the diversity of morphologies, microbial communities, extracellular proteins and polysaccharides between the biofilm and S-sludge. Contrast to biofilm, the denitrification was much more extensive performed in S-sludge. Furthermore, many microbial cells in the biofilm acted as the backbone of aggregates and maintained the structure stability. An extracellular protein observed only in the biofilm can promote the cell adhesion. In contrast, more extracellular proteins related to catalytic activity in the S-sludge could decrease the compactness of floc. In addition, the monosaccharide compositions from the two aggregates were various. These results could elucidate how the diversities of architecture and biochemical process between the two aggregates occurred.
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Affiliation(s)
- Peng Zhang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Jin-Song Guo
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China; Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Yu Shen
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Peng Yan
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - You-Peng Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China; Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
| | - Han Wang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Ji-Xiang Yang
- Key Laboratory of Reservoir Aquatic Environment of CAS, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Fang Fang
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Chun Li
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
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Yin C, Meng F, Chen GH. Spectroscopic characterization of extracellular polymeric substances from a mixed culture dominated by ammonia-oxidizing bacteria. WATER RESEARCH 2015; 68:740-749. [PMID: 25462778 DOI: 10.1016/j.watres.2014.10.046] [Citation(s) in RCA: 263] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 09/30/2014] [Accepted: 10/20/2014] [Indexed: 06/04/2023]
Abstract
Extracellular polymeric substances (EPS) of aerobic (AerAOB) and anaerobic ammonium-oxidizing bacteria (AnAOB) are expected to have a significant impact on the performance of autotrophic nitrogen removal in engineered systems. However, there are a few investigations of the EPS of AerAOB and AnAOB, and the results are contradictory. In this study, photometric measurements indicated that the EPS of AerAOB- (31.74 ± 1.48 mg/g-VSS, volatile suspended solids) and AnAOB-enriched cultures (30.12 ± 1.52 mg/g-VSS) contained more polysaccharides than did conventional activated sludge from a municipal wastewater treatment facility (10.76 ± 0.83 mg/g-VSS). In addition, the EPS of the AnAOB-enriched culture was dominated by proteins, leading to a considerably higher protein/polysaccharide ratio (2.64 ± 0.12) than those of the AerAOB-enriched culture (0.56 ± 0.03) and conventional activated sludge (1.96 ± 0.09). Characterization using Fourier transform infrared spectroscopy (FTIR) revealed the dominance of amide bands and/or polysaccharide-associated bands in the EPS of AnAOB and AerAOB. These results corroborate the data from the photometric measurements. In addition, the EPS of AnAOB (23.1% ± 1.2%) and AerAOB (21.9% ± 1.1%) had a higher portion of α-helices, which is the key protein secondary structure that determines flocculation or cell aggregation, in the amide I band than that of activated sludge (16.7% ± 0.8%). X-ray photoelectron spectroscopy (XPS) characterization also revealed significantly different functionalities among the EPS of the three mixed cultures; e.g., O-(C,H), which indicates the presence of polysaccharides, was richer in the EPS of AerAOB, whereas protonated amines, which are commonly found in amino acids and amino sugars, accounted for a large portion of the EPS of AnAOB. The results of this study can potentially expand our knowledge of the microbial aggregates responsible for autotrophic nitrogen removal.
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Affiliation(s)
- Cuiqin Yin
- SYSU-HKUST Research Center for Innovative Environmental Technology, School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China
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Zhang P, Fang F, Chen YP, Shen Y, Zhang W, Yang JX, Li C, Guo JS, Liu SY, Huang Y, Li S, Gao X, Yan P. Composition of EPS fractions from suspended sludge and biofilm and their roles in microbial cell aggregation. CHEMOSPHERE 2014; 117:59-65. [PMID: 24968163 DOI: 10.1016/j.chemosphere.2014.05.070] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 06/03/2023]
Abstract
The adhesion and aggregation properties of microbial cell are closely related to extracellular polymeric substances (EPS). In this work, the composition and physicochemical characteristics of EPS in biofilm and suspended sludge (S-sludge) were determined to evaluate their roles in microbial cell aggregation. Raman spectroscopy and three-dimensional fluorescence spectra have been employed to reveal each EPS fraction in different composition. The flocculating capacity of each EPS fraction in the S-sludge shows extraordinary activity, comparing its counterpart in biofilm. Microbial cell surfaces present high hydrophobicity and increased zeta potentials upon EPS extraction. In addition, the respective contribution of EPS to cell aggregating was elucidated. The contribution of combined SEPS and LB-EPS was 23% for S-sludge sample, whereas that was negligible for biofilm sample. The contribution of LB-EPS and TB-EPS were 16% and 30% for S-sludge sample, and -6% and negligible for biofilm sample, respectively. Therefore, EPS promoted the S-sludge cells to aggregate, while in contrast, they showed a negligible or negative effect on the biofilm cells aggregating.
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Affiliation(s)
- Peng Zhang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Fang Fang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - You-Peng Chen
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
| | - Yu Shen
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Wei Zhang
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Ji-Xiang Yang
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Chun Li
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Jin-Song Guo
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China; Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China.
| | - Shao-Yang Liu
- Department of Chemistry and Physics, Troy University, Troy, AL 36082, USA
| | - Yang Huang
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Shan Li
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Xu Gao
- Key Laboratory of Three Gorges Reservoir Region's Eco-Environments of MOE, Chongqing University, Chongqing 400045, China
| | - Peng Yan
- Key Laboratory of Reservoir Aquatic Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
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Pellicer-Nàcher C, Domingo-Félez C, Mutlu AG, Smets BF. Critical assessment of extracellular polymeric substances extraction methods from mixed culture biomass. WATER RESEARCH 2013; 47:5564-5574. [PMID: 23866135 DOI: 10.1016/j.watres.2013.06.026] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 06/09/2013] [Accepted: 06/16/2013] [Indexed: 06/02/2023]
Abstract
Extracellular polymeric substances (EPS) have a presumed determinant role in the structure, architecture, strength, filterability, and settling behaviour of microbial solids in biological wastewater treatment processes. Consequently, numerous EPS extraction protocols have recently been published that aim to optimize the trade off between high EPS recovery and low cell lysis. Despite extensive efforts, the obtained results are often contradictory, even when analysing similar biomass samples and using similar experimental conditions, which greatly complicates the selection of an extraction protocol. This study presents a rigorous and critical assessment of existing physical and chemical EPS extraction methods applied to mixed-culture biomass samples (nitrifying, nitritation-anammox, and activated sludge biomass). A novel fluorescence-based method was developed and calibrated to quantify the lysis potential of different EPS extraction protocols. We concluded that commonly used methods to assess cell lysis (DNA concentrations or G6PDH activities in EPS extracts) do not correlate with cell viability. Furthermore, we discovered that the presence of certain chemicals in EPS extracts results in severe underestimation of protein and carbohydrate concentrations by using standard analytical methods. Keeping both maximum EPS extraction yields and minimal biomass lysis as criteria, it was identified a sonication-based extraction method as the best to determine and compare tightly-bound EPS fractions in different biomass samples. Protein was consistently the main EPS component in all analysed samples. However, EPS from nitrifying enrichments was richer in DNA, the activated sludge EPS had a higher content in humic acids and carbohydrates, and the nitritation-anammox EPS, while similar in composition to the nitrifier EPS, had a lower fraction of hydrophobic biopolymers. In general, the easily-extractable EPS fraction was more abundant in carbohydrates and humic substances, while DNA could only be found in tightly bound EPS fractions. In conclusion, the methodology presented herein supports the rational selection of analytical tools and EPS extraction protocols in further EPS characterization studies.
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Affiliation(s)
- Carles Pellicer-Nàcher
- Department of Environmental Engineering, Technical University of Denmark, Miljøvej Building 113, 2800 Kongens Lyngby, Denmark.
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