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Mahadevaswamy UR, Mugunthan S, Seviour T, Kjelleberg S, Lim S. Evaluating a polymicrobial biofilm model for structural components by co-culturing Komagataeibacter hansenii produced bacterial cellulose with Pseudomonas aeruginosa PAO1. Biofilm 2024; 7:100176. [PMID: 38322579 PMCID: PMC10845243 DOI: 10.1016/j.bioflm.2024.100176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 12/21/2023] [Accepted: 01/04/2024] [Indexed: 02/08/2024] Open
Abstract
A polymicrobial biofilm model of Komagataeibacter hansenii and Pseudomonas aeruginosa was developed to understand whether a pre-existing matrix affects the ability of another species to build a biofilm. P. aeruginosa was inoculated onto the preformed K. hansenii biofilm consisting of a cellulose matrix. P. aeruginosa PAO1 colonized and infiltrated the K. hansenii bacterial cellulose biofilm (BC), as indicated by the presence of cells at 19 μm depth in the translucent hydrogel matrix. Bacterial cell density increased along the imaged depth of the biofilm (17-19 μm). On day 5, the average bacterial count across sections was 67 ± 4 % P. aeruginosa PAO1 and 33 ± 6 % K. hansenii. Biophysical characterization of the biofilm indicated that colonization by P. aeruginosa modified the biophysical properties of the BC matrix, which inlcuded increased density, heterogeneity, degradation temperature and thermal stability, and reduced crystallinity, swelling ability and moisture content. This further indicates colonization of the biofilm by P. aeruginosa. While eDNA fibres - a key viscoelastic component of P. aeruginosa biofilm - were present on the surface of the co-cultured biofilm on day 1, their abundance decreased over time, and by day 5, no eDNA was observed, either on the surface or within the matrix. P. aeruginosa-colonized biofilm devoid of eDNA retained its mechanical properties. The observations demonstrate that a pre-existing biofilm scaffold of K. hansenii inhibits P. aeruginosa PAO1 eDNA production and suggest that eDNA production is a response by P. aeruginosa to the viscoelastic properties of its environment.
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Affiliation(s)
- Usha Rani Mahadevaswamy
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore
| | - Sudarsan Mugunthan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
- Centre for Water Technology (WATEC), Department of Biological and Chemical Engineering, Aarhus University, Aarhus, 8000, Denmark
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, Australia
| | - Sierin Lim
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore
- Nanyang Environment and Water Research Institute, Nanyang Technological University, Singapore
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2
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Mugunthan S, Wong LL, Winnerdy FR, Summers S, Bin Ismail MH, Foo YH, Jaggi TK, Meldrum OW, Tiew PY, Chotirmall SH, Rice SA, Phan AT, Kjelleberg S, Seviour T. RNA is a key component of extracellular DNA networks in Pseudomonas aeruginosa biofilms. Nat Commun 2023; 14:7772. [PMID: 38012164 PMCID: PMC10682433 DOI: 10.1038/s41467-023-43533-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 11/13/2023] [Indexed: 11/29/2023] Open
Abstract
The extracellular matrix of bacterial biofilms consists of diverse components including polysaccharides, proteins and DNA. Extracellular RNA (eRNA) can also be present, contributing to the structural integrity of biofilms. However, technical difficulties related to the low stability of RNA make it difficult to understand the precise roles of eRNA in biofilms. Here, we show that eRNA associates with extracellular DNA (eDNA) to form matrix fibres in Pseudomonas aeruginosa biofilms, and the eRNA is enriched in certain bacterial RNA transcripts. Degradation of eRNA associated with eDNA led to a loss of eDNA fibres and biofilm viscoelasticity. Compared with planktonic and biofilm cells, the biofilm matrix was enriched in specific mRNA transcripts, including lasB (encoding elastase). The mRNA transcripts colocalised with eDNA fibres in the biofilm matrix, as shown by single molecule inexpensive FISH microscopy (smiFISH). The lasB mRNA was also observed in eDNA fibres in a clinical sputum sample positive for P. aeruginosa. Thus, our results indicate that the interaction of specific mRNAs with eDNA facilitates the formation of viscoelastic networks in the matrix of Pseudomonas aeruginosa biofilms.
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Affiliation(s)
- Sudarsan Mugunthan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore
| | - Lan Li Wong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore
| | | | - Stephen Summers
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore
- St John's Island National Marine Laboratory c/o Tropical Marine Science Institute, National University of Singapore, 119227, Singapore
| | | | - Yong Hwee Foo
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore
- Institute for Digital Molecular Analytics and Science (IDMxS), Nanyang Technological University, Singapore, 636921, Singapore
| | - Tavleen Kaur Jaggi
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
| | - Oliver W Meldrum
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
| | - Pei Yee Tiew
- Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore, Singapore
| | - Sanjay H Chotirmall
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 636921, Singapore
- Department of Respiratory and Critical Care Medicine, Tan Tock Seng Hospital, Singapore, Singapore
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore
- The iThree Institute, University of Technology Sydney, Sydney, 2007, Australia
- CSIRO, Agriculture and Food, Westmead and Microbiomes for One Systems Health, Canberra, Australia
| | - Anh Tuân Phan
- School of Physical & Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore.
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore.
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, 2052, Australia.
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore.
- Centre for Water Technology (WATEC), Department of Biological and Chemical Engineering, Aarhus University, Aarhus, 8000, Denmark.
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3
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Sen O, Hinks J, Lin Q, Lin Q, Kjelleberg S, Rice SA, Seviour T. Escherichia coli displays a conserved membrane proteomic response to a range of alcohols. Biotechnol Biofuels Bioprod 2023; 16:147. [PMID: 37789404 PMCID: PMC10546733 DOI: 10.1186/s13068-023-02401-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 09/18/2023] [Indexed: 10/05/2023]
Abstract
BACKGROUND Alcohol is a good and environment-friendly fuel that can be microbially produced, capable of eliminating many of the limitations of the present-day fossil fuels. However, the inherent toxic nature of alcohols to the microbial cells leads to end-product inhibition that limits large-scale alcohol production by fermentation. Fundamental knowledge about the stress responses of microorganisms to alcohols would greatly facilitate to improve the microbial alcohol tolerance. The current study elucidates and compares the changes in the membrane proteome of Escherichia coli in response to a range of alcohols. RESULTS Although alcohol toxicity increased exponentially with alcohol chain length (2-6 carbon), similar stress responses were observed in the inner and outer membrane proteome of E. coli in the presence of 2-, 4- and 6-carbon alcohols at the MIC50. This pertains to: (1) increased levels of inner membrane transporters for uptake of energy-producing metabolites, (2) reduced levels of non-essential proteins, associated with anaerobic, carbon starvation and osmotic stress, for energy conservation, (3) increased levels of murein degrading enzymes (MltA, EmtA, MliC and DigH) promoting cell elongation and 4) reduced levels of most outer membrane β-barrel proteins (LptD, FadL, LamB, TolC and BamA). Major outer membrane β-barrel protein OmpC, which is known to contribute to ethanol tolerance and membrane integrity, was notably reduced by alcohol stress. While LPS is important for OmpC trimerisation, LPS release by EDTA did not lower OmpC levels. This suggests that LPS release, which is reported under alcohol stress, does not contribute to the reduced levels of OmpC in the presence of alcohol. CONCLUSIONS Since alcohol primarily targets the integrity of the membrane, maintenance of outer membrane OmpC levels in the presence of alcohol might help in the survival of E. coli to higher alcohol concentrations. The study provides important information about the membrane protein responses of E. coli to a range of alcohols, which can be used to develop targeted strategies for increased microbial alcohol tolerance and hence bioalcohol production.
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Affiliation(s)
- Oishi Sen
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Jamie Hinks
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Qifeng Lin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Qingsong Lin
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, 2052, Australia
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- The Australian Institute for Microbiology and Immunology, University of Technology Sydney, Sydney, 2007, Australia
- CSIRO, Agriculture and Food, Westmead and Microbiomes for One Systems Health, Sydney, Australia
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.
- WATEC Aarhus University Centre for Water Technology, Universitetsbyen 36, Bldg 1783, 8000, Aarhus, Denmark.
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4
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Flemming HC, van Hullebusch ED, Neu TR, Nielsen PH, Seviour T, Stoodley P, Wingender J, Wuertz S. The biofilm matrix: multitasking in a shared space. Nat Rev Microbiol 2023; 21:70-86. [PMID: 36127518 DOI: 10.1038/s41579-022-00791-0] [Citation(s) in RCA: 101] [Impact Index Per Article: 101.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2022] [Indexed: 01/20/2023]
Abstract
The biofilm matrix can be considered to be a shared space for the encased microbial cells, comprising a wide variety of extracellular polymeric substances (EPS), such as polysaccharides, proteins, amyloids, lipids and extracellular DNA (eDNA), as well as membrane vesicles and humic-like microbially derived refractory substances. EPS are dynamic in space and time and their components interact in complex ways, fulfilling various functions: to stabilize the matrix, acquire nutrients, retain and protect eDNA or exoenzymes, or offer sorption sites for ions and hydrophobic substances. The retention of exoenzymes effectively renders the biofilm matrix an external digestion system influencing the global turnover of biopolymers, considering the ubiquitous relevance of biofilms. Physico-chemical and biological interactions and environmental conditions enable biofilm systems to morph into films, microcolonies and macrocolonies, films, ridges, ripples, columns, pellicles, bubbles, mushrooms and suspended aggregates - in response to the very diverse conditions confronting a particular biofilm community. Assembly and dynamics of the matrix are mostly coordinated by secondary messengers, signalling molecules or small RNAs, in both medically relevant and environmental biofilms. Fully deciphering how bacteria provide structure to the matrix, and thus facilitate and benefit from extracellular reactions, remains the challenge for future biofilm research.
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Affiliation(s)
- Hans-Curt Flemming
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.
| | | | - Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany
| | - Per H Nielsen
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Thomas Seviour
- Aarhus University Centre for Water Technology, Department of Biological and Chemical Engineering, Aarhus University, Aarhus, Denmark
| | - Paul Stoodley
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, USA.,Department of Orthopaedics, The Ohio State University, Columbus, OH, USA
| | - Jost Wingender
- University of Duisburg-Essen, Biofilm Centre, Department of Aquatic Microbiology, Essen, Germany
| | - Stefan Wuertz
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
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5
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Wong LL, Mugunthan S, Kundukad B, Ho JCS, Rice SA, Hinks J, Seviour T, Parikh AN, Kjelleberg S. Microbial biofilms are shaped by the constant dialogue between biological and physical forces in the extracellular matrix. Environ Microbiol 2023; 25:199-208. [PMID: 36502515 DOI: 10.1111/1462-2920.16306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Affiliation(s)
- Lan Li Wong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Sudarsan Mugunthan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Binu Kundukad
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - James Chin Shing Ho
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Institute for Digital Molecular Analytics and Science, Nanyang Technological University, Singapore, Singapore
| | - Scott A Rice
- CSIRO, Agriculture and Food, Microbiomes for One Systems Health, Canberra, Australia
| | - Jamie Hinks
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,WATEC Aarhus University Centre for Water Technology, Aarhus, Denmark
| | - Atul N Parikh
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,Institute for Digital Molecular Analytics and Science, Nanyang Technological University, Singapore, Singapore.,Department of Biomedical Engineering, University of California, Davis, California, USA
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
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6
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Lu Y, Natarajan G, Nguyen TQN, Thi SS, Arumugam K, Seviour T, Williams RBH, Wuertz S, Law Y. Controlling anammox speciation and biofilm attachment strategy using N-biotransformation intermediates and organic carbon levels. Sci Rep 2022; 12:21720. [PMID: 36522527 PMCID: PMC9755228 DOI: 10.1038/s41598-022-26069-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
Conventional nitrogen removal in wastewater treatment requires a high oxygen and energy input. Anaerobic ammonium oxidation (anammox), the single-step conversion of ammonium and nitrite to nitrogen gas, is a more energy and cost effective alternative applied extensively to sidestream wastewater treatment. It would also be a mainstream treatment option if species diversity and physiology were better understood. Anammox bacteria were enriched up to 80%, 90% and 50% relative abundance, from a single inoculum, under standard enrichment conditions with either stepwise-nitrite and ammonia concentration increases (R1), nitric oxide supplementation (R2), or complex organic carbon from mainstream wastewater (R3), respectively. Candidatus Brocadia caroliniensis predominated in all reactors, but a shift towards Ca. Brocadia sinica occurred at ammonium and nitrite concentrations > 270 mg NH4-N L-1 and 340 mg NO2-N L-1 respectively. With NO present, heterotrophic growth was inhibited, and Ca. Jettenia coexisted with Ca. B. caroliniensis before diminishing as nitrite increased to 160 mg NO2-N L-1. Organic carbon supplementation led to the emergence of heterotrophic communities that coevolved with Ca. B. caroliniensis. Ca. B. caroliniensis and Ca. Jettenia preferentially formed biofilms on surfaces, whereas Ca. Brocadia sinica formed granules in suspension. Our results indicate that multiple anammox bacteria species co-exist and occupy sub-niches in anammox reactors, and that the dominant population can be reversibly shifted by, for example, changing nitrogen load (i.e. high nitrite concentration favors Ca. Brocadia caroliniensis). Speciation has implications for wastewater process design, where the optimum cell immobilization strategy (i.e. carriers vs granules) depends on which species dominates.
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Affiliation(s)
- Yang Lu
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551 Singapore ,grid.1003.20000 0000 9320 7537Present Address: The Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD 4072 Australia
| | - Gayathri Natarajan
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551 Singapore
| | - Thi Quynh Ngoc Nguyen
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551 Singapore ,grid.185448.40000 0004 0637 0221Present Address: Agency for Science, Technology and Research, Singapore, 138632 Singapore
| | - Sara Swa Thi
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551 Singapore
| | - Krithika Arumugam
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551 Singapore
| | - Thomas Seviour
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551 Singapore ,grid.7048.b0000 0001 1956 2722Centre for Water Technology (WATEC) & Department of Biological and Chemical Engineering, Aarhus University, Universitetsbyen 36, 8000 Aarhus C, Denmark
| | - Rohan B. H. Williams
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, Singapore, 119077 Singapore
| | - Stefan Wuertz
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551 Singapore ,grid.59025.3b0000 0001 2224 0361School of Civil and Environmental Engineering, Nanyang Technological University, Singapore, 639798 Singapore
| | - Yingyu Law
- grid.484638.50000 0004 7703 9448Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551 Singapore
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7
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Su Z, Liu T, Seviour T, Li S, Tian L, Zhang G, Yu W. Identifying active concentrations of biopolymers for enhancing membrane nanofiltration performance: From bench-scale tests to real production considerations. Sci Total Environ 2022; 818:151808. [PMID: 34808182 DOI: 10.1016/j.scitotenv.2021.151808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/15/2021] [Accepted: 11/15/2021] [Indexed: 06/13/2023]
Abstract
In the last decades, membrane-based nanofiltration (NF) technique has been widely applied for safe and high-quality drinking water production worldwide. NF membrane fouling has become one of the main obstacles in its application due to high operation cost, and thus numerous efforts have been made. However, there is still a large disconnect between academic findings and their applications. Hence, novel approaches for further exploitation and application are required based on feasibility of implementation. In this work, an optimized design of membrane-based NF plants was proposed, inspired by natural biopolymers present in feed water of NF unit. Specifically, we found beneficial functions of biopolymers, including NF membrane fouling alleviation and effluent quality improvement; these advantages could only be "activated" under a certain concentration range of biopolymers (0-1 mg C/L here), and less or more is not acceptable. This indicated that a NF unit is better to follow a microfiltration (MF) (instead of ultrafiltration (UF) which removes biopolymers) process during which natural biopolymers could be remained; also, this approach is suggested to be valid across different seasons when biopolymers' concentrations could be controlled within an "activated" range by mixing MF and UF permeates. Furthermore, three representative reference biopolymers with different, confirmed spatial structures and molecular weight (MW) were used to elucidate the micro-level functions of natural biopolymers on NF membranes, suggesting that cake layer structures shaped by various biopolymers determine the resulting NF performance. Overall, this innovative proposal is expected to be considered and adopted towards more energy-efficient NF technology for drinking water supply.
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Affiliation(s)
- Zhaoyang Su
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; Center for the Environmental Implications of Nanotechnology, Duke University, Durham, NC 27708, United States.
| | - Ting Liu
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Thomas Seviour
- Aarhus University Centre for Water Technology (WATEC), Biological and Chemical Engineering, Aarhus 8000, Denmark; Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore.
| | - Shuo Li
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Long Tian
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Guotao Zhang
- School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, China.
| | - Wenzheng Yu
- State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
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8
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Cruz H, Yap Gabon M, Salehin S, Seviour T, Laycock B, Pikaar I. Magnetic poly(acrylic acid)-based hydrogels for rapid ammonium sorption and efficient sorbent separation from sewage. Environ Sci Ecotechnol 2021; 6:100097. [PMID: 36159177 PMCID: PMC9488083 DOI: 10.1016/j.ese.2021.100097] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 05/10/2021] [Accepted: 05/11/2021] [Indexed: 06/16/2023]
Abstract
Ammonium sorption and recovery processes typically take place in conventional packed columns, with a configuration that enables maximum sorption by the sorbents. However, batch or semi-continuous operations in packed columns have associated issues such as scaling and frequent backwashing requirements, which are economically prohibitive. As an alternative, ammonium sorption could occur in well-mixed continuously stirred tanks, which would allow for the ammonium sorption process to be retrofitted in existing wastewater treatment plants, provided that efficient sorbent separation can be achieved. This study demonstrates, for the first time, the preparation of magnetic poly(acrylic acid)-based (PAA) ammonium sorbents through the incorporation of magnetic (Fe3O4) nanoparticles (MNP) produced via scalable and cost-effective electrochemical synthesis. The MNP and PAA hydrogels were synthesized independently and the MNPs subsequently integrated into the PAA hydrogel network by particle diffusion and physical entrapment. No adverse effects on swelling and ammonium sorption following immersion in either synthetic or real sewage were observed after MNPs were incorporated into the hydrogels. Importantly, PAA-MNP hydrogels demonstrated high ammonium sorption efficiencies (80-93%) in real sewage and achieved rapid ammonium recovery of 73 ± 1.1% within 15 min of mild acid washing (pH 4) 15 min at a maximum recovery.
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Affiliation(s)
- Heidy Cruz
- School of Civil Engineering, The University of Queensland, Brisbane, Queensland, 4072, Australia
- Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore, 117576, Singapore
| | - Miriam Yap Gabon
- School of Civil Engineering, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Sirajus Salehin
- School of Civil Engineering, The University of Queensland, Brisbane, Queensland, 4072, Australia
- Advanced Water Management Center, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Thomas Seviour
- WATEC Aarhus University Centre for Water Technology, Nørrebrogade 44, Bldg 1783, 8000, Aarhus, Denmark
| | - Bronwyn Laycock
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland, 4072, Australia
| | - Ilje Pikaar
- School of Civil Engineering, The University of Queensland, Brisbane, Queensland, 4072, Australia
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9
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Seviour T, Winnerdy FR, Wong LL, Shi X, Mugunthan S, Foo YH, Castaing R, Adav SS, Subramoni S, Kohli GS, Shewan HM, Stokes JR, Rice SA, Phan AT, Kjelleberg S. The biofilm matrix scaffold of Pseudomonas aeruginosa contains G-quadruplex extracellular DNA structures. NPJ Biofilms Microbiomes 2021; 7:27. [PMID: 33741996 PMCID: PMC7979868 DOI: 10.1038/s41522-021-00197-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 02/12/2021] [Indexed: 12/31/2022] Open
Abstract
Extracellular DNA, or eDNA, is recognised as a critical biofilm component; however, it is not understood how it forms networked matrix structures. Here, we isolate eDNA from static-culture Pseudomonas aeruginosa biofilms using ionic liquids to preserve its biophysical signatures of fluid viscoelasticity and the temperature dependency of DNA transitions. We describe a loss of eDNA network structure as resulting from a change in nucleic acid conformation, and propose that its ability to form viscoelastic structures is key to its role in building biofilm matrices. Solid-state analysis of isolated eDNA, as a proxy for eDNA structure in biofilms, reveals non-canonical Hoogsteen base pairs, triads or tetrads involving thymine or uracil, and guanine, suggesting that the eDNA forms G-quadruplex structures. These are less abundant in chromosomal DNA and disappear when eDNA undergoes conformation transition. We verify the occurrence of G-quadruplex structures in the extracellular matrix of intact static and flow-cell biofilms of P. aeruginosa, as displayed by the matrix to G-quadruplex-specific antibody binding, and validate the loss of G-quadruplex structures in vivo to occur coincident with the disappearance of eDNA fibres. Given their stability, understanding how extracellular G-quadruplex structures form will elucidate how P. aeruginosa eDNA builds viscoelastic networks, which are a foundational biofilm property.
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Affiliation(s)
- Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore. .,WATEC Aarhus University Centre for Water Technology, Aarhus, Denmark.
| | - Fernaldo Richtia Winnerdy
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Lan Li Wong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Xiangyan Shi
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Sudarsan Mugunthan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Yong Hwee Foo
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Remi Castaing
- Materials and Chemical Characterisation Facility (MC2), University of Bath, Bath, UK
| | - Sunil S Adav
- Singapore Phenome Centre, Nanyang Technological University, Singapore, Singapore
| | - Sujatha Subramoni
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Gurjeet Singh Kohli
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Heather M Shewan
- School of Chemical Engineering, University of Queensland, Brisbane, QLD, Australia
| | - Jason R Stokes
- School of Chemical Engineering, University of Queensland, Brisbane, QLD, Australia
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.,The iThree Institute, University of Technology Sydney, Sydney, NSW, Australia.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Anh Tuân Phan
- School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore. .,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore. .,School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW, Australia.
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10
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Cruz H, Laycock B, Strounina E, Seviour T, Oehmen A, Pikaar I. Modified Poly(acrylic acid)-Based Hydrogels for Enhanced Mainstream Removal of Ammonium from Domestic Wastewater. Environ Sci Technol 2020; 54:9573-9583. [PMID: 32551594 DOI: 10.1021/acs.est.9b07032] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Rapid and continuous ammonium adsorption from mainstream coupled with side-stream ammonium recovery and adsorbent regeneration could enable ammonium recovery from domestic wastewater. This study describes the use of tailored poly(acrylic acid)-based (NaPAA) hydrogels as effective sorbents for ammonium removal from domestic wastewater. Modified NaPAA hydrogels having 60% ionization and 4.8 mol % N',N'-methylenebisacrylamide as the cross-linker reduced the overall swelling by 92% from 407 to 31 g/g because of higher cross-linking density. At hydrogel loadings of 2.5-7.5 g/L, the NaPAA hydrogels achieved ammonium concentrations of 8.3 ± 0.6 to 10.1 ± 0.1 mg/L NH4-N, which corresponds to removal efficiencies of 53-77% after 10 min of contact time in real domestic wastewater. At the same hydrogel loadings, the ammonium removal efficiency of NaPAA hydrogels in synthetic wastewater was found to be comparable to that in real sewage (71% vs 69%, respectively), suggesting that the sorption performance is only marginally affected by organic constituents found in domestic wastewater. In addition, the NaPAA hydrogels removed 25-51% ammonium in 10 min from synthetic streams having 200-400% higher ionic strengths than those commonly observed in sewage. Furthermore, simulation studies showed that a discharge concentration of ∼1.9 mg/L NH4-N, well below the commonly applied discharge limits in most regions, can be achieved using mainstream ammonium removal by NaPAA hydrogels followed by biological assimilation from the growth of ordinary heterotrophic organisms.
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Affiliation(s)
- Heidy Cruz
- School of Civil Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Bronwyn Laycock
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ekaterina Strounina
- Center for Advanced Imaging, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore
| | - Adrian Oehmen
- School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Ilje Pikaar
- School of Civil Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia
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11
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Guo J, Chia GW, Berezhnoy NV, Cazenave-Gassiot A, Kjelleberg S, Hinks J, Mu Y, Seviour T. Bacterial lipopolysaccharide core structures mediate effects of butanol ingress. Biochimica et Biophysica Acta (BBA) - Biomembranes 2020; 1862:183150. [DOI: 10.1016/j.bbamem.2019.183150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 11/07/2019] [Accepted: 12/06/2019] [Indexed: 12/13/2022]
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12
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Boleij M, Seviour T, Wong LL, van Loosdrecht MCM, Lin Y. Solubilization and characterization of extracellular proteins from anammox granular sludge. Water Res 2019; 164:114952. [PMID: 31408759 DOI: 10.1016/j.watres.2019.114952] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 07/18/2019] [Accepted: 08/03/2019] [Indexed: 06/10/2023]
Abstract
Elucidating the extracellular polymeric substances (EPS) of anammox granular sludge is important for stable nitrogen removal processes in wastewater treatment. However, due to a lack of standardized methods for extraction and characterization, the composition of anammox granule EPS remains mostly unknown. In this study, alkaline (NaOH) and ionic liquid (IL) extractions were compared in terms of the proteins they extracted from different "Candidatus Brocadia" cultures. We aimed to identify structural proteins and evaluated to which extend these extraction methods bias the outcome of EPS characterization. Extraction was focussed on solubilization of the EPS matrix, and the NaOH and IL extraction recovered on average 20% and 26% of the VSS, respectively. Using two extraction methods targeting different intermolecular interactions increased the possibility of identifying structural extracellular proteins. Of the extracted proteins, ∼40% were common between the extraction methods. The high number of common abundant proteins between the extraction methods, illustrated how extraction biases can be reduced when solubility of the granular sludge is enhanced. Physicochemical analyses of the granules indicated that extracellular structural matrix proteins likely have β-sheet dominated secondary structures. These β-sheet structures were measured in EPS extracted with both methods. The high number of uncharacterized proteins and possible moonlighting proteins confounded identifying structural (i.e. β-sheet dominant) proteins. Nonetheless, new candidates for structural matrix proteins are described. Further current bottlenecks in assigning specific proteins to key extracellular functions in anammox granular sludge are discussed.
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Affiliation(s)
- Marissa Boleij
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ, Delft, the Netherlands
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore
| | - Lan Li Wong
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore
| | - Mark C M van Loosdrecht
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ, Delft, the Netherlands
| | - Yuemei Lin
- Department of Biotechnology, Delft University of Technology, van der Maasweg 9, 2629, HZ, Delft, the Netherlands.
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13
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Guo J, Ho JCS, Chin H, Mark AE, Zhou C, Kjelleberg S, Liedberg B, Parikh AN, Cho NJ, Hinks J, Mu Y, Seviour T. Response of microbial membranes to butanol: interdigitation vs. disorder. Phys Chem Chem Phys 2019; 21:11903-11915. [PMID: 31125035 DOI: 10.1039/c9cp01469a] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biobutanol production by fermentation is potentially a sustainable alternative to butanol production from fossil fuels. However, the toxicity of butanol to fermentative bacteria, resulting largely from cell membrane fluidization, limits production titers and is a major factor limiting the uptake of the technology. Here, studies were undertaken, in vitro and in silico, on the butanol effects on a representative bacterial (i.e. Escherichia coli) inner cell membrane. A critical butanol : lipid ratio for stability of 2 : 1 was observed, computationally, consistent with complete interdigitation. However, at this ratio the bilayer was ∼20% thicker than for full interdigitation. Furthermore, butanol intercalation induced acyl chain bending and increased disorder, measured as a 27% lateral diffusivity increase experimentally in a supported lipid bilayer. There was also a monophasic Tm reduction in butanol-treated large unilamellar vesicles. Both behaviours are inconsistent with an interdigitated gel. Butanol thus causes only partial interdigitation at physiological temperatures, due to butanol accumulating at the phospholipid headgroups. Acyl tail disordering (i.e. splaying and bending) fills the subsequent voids. Finally, butanol short-circuits the bilayer and creates a coupled system where interdigitated and splayed phospholipids coexist. These findings will inform the design of strategies targeting bilayer stability for increasing biobutanol production titers.
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Affiliation(s)
- Jingjing Guo
- Singapore Centre for Environmental Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore.
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14
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Zhou C, Chia GWN, Ho JCS, Moreland AS, Seviour T, Liedberg B, Parikh AN, Kjelleberg S, Hinks J, Bazan GC. A Chain-Elongated Oligophenylenevinylene Electrolyte Increases Microbial Membrane Stability. Adv Mater 2019; 31:e1808021. [PMID: 30908801 DOI: 10.1002/adma.201808021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/18/2019] [Indexed: 06/09/2023]
Abstract
A novel conjugated oligoelectrolyte (COE) material, named S6, is designed to have a lipid-bilayer stabilizing topology afforded by an extended oligophenylenevinylene backbone. S6 intercalates biological membranes acting as a hydrophobic support for glycerophospholipid acyl chains. Indeed, Escherichia coli treated with S6 exhibits a twofold improvement in butanol tolerance, a relevant feature to achieve within the general context of modifying microorganisms used in biofuel production. Filamentous growth, a morphological stress response to butanol toxicity in E. coli, is observed in untreated cells after incubation with 0.9% butanol (v/v), but is mitigated by S6 treatment. Real-time fluorescence imaging using giant unilamellar vesicles reveals the extent to which S6 counters membrane instability. Moreover, S6 also reduces butanol-induced lipopolysaccharide release from the outer membrane to further maintain cell integrity. These findings highlight a deliberate effort in the molecular design of a chain-elongated COE to stabilize microbial membranes against environmental challenges.
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Affiliation(s)
- Cheng Zhou
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Geraldine W N Chia
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- Interdisciplinary Graduate School, Nanyang Technological University, Singapore, 639798, Singapore
| | - James C S Ho
- Centre for Biomimetic Sensor Science, School of Materials Science & Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Alex S Moreland
- Center for Polymers and Organic Solids, Departments of Chemistry & Biochemistry and Materials, University of California, Santa Barbara, CA, 93106, USA
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Bo Liedberg
- Interdisciplinary Graduate School, Nanyang Technological University, Singapore, 639798, Singapore
- Centre for Biomimetic Sensor Science, School of Materials Science & Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Atul N Parikh
- Centre for Biomimetic Sensor Science, School of Materials Science & Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- Department of Chemistry, Chemical Engineering, Biomedical Engineering,, and Materials Science & Engineering, University of California, Davis, CA, 95616, USA
| | - Staffan Kjelleberg
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Jamie Hinks
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639798, Singapore
| | - Guillermo C Bazan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 639798, Singapore
- Center for Polymers and Organic Solids, Departments of Chemistry & Biochemistry and Materials, University of California, Santa Barbara, CA, 93106, USA
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15
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Seviour T, Derlon N, Dueholm MS, Flemming HC, Girbal-Neuhauser E, Horn H, Kjelleberg S, van Loosdrecht MCM, Lotti T, Malpei MF, Nerenberg R, Neu TR, Paul E, Yu H, Lin Y. Extracellular polymeric substances of biofilms: Suffering from an identity crisis. Water Res 2019; 151:1-7. [PMID: 30557778 DOI: 10.1016/j.watres.2018.11.020] [Citation(s) in RCA: 149] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 11/02/2018] [Accepted: 11/10/2018] [Indexed: 06/09/2023]
Abstract
Microbial biofilms can be both cause and cure to a range of emerging societal problems including antimicrobial tolerance, water sanitation, water scarcity and pollution. The identities of extracellular polymeric substances (EPS) responsible for the establishment and function of biofilms are poorly understood. The lack of information on the chemical and physical identities of EPS limits the potential to rationally engineer biofilm processes, and impedes progress within the water and wastewater sector towards a circular economy and resource recovery. Here, a multidisciplinary roadmap for addressing this EPS identity crisis is proposed. This involves improved EPS extraction and characterization methodologies, cross-referencing between model biofilms and full-scale biofilm systems, and functional description of isolated EPS with in situ techniques (e.g. microscopy) coupled with genomics, proteomics and glycomics. The current extraction and spectrophotometric characterization methods, often based on the principle not to compromise the integrity of the microbial cells, should be critically assessed, and more comprehensive methods for recovery and characterization of EPS need to be developed.
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Affiliation(s)
- Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore.
| | - Nicolas Derlon
- EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Department of Process Engineering, CH-8600, Dübendorf, Switzerland
| | - Morten Simonsen Dueholm
- Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Aalborg, Denmark
| | - Hans-Curt Flemming
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore; University of Duisburg-Essen, Faculty of Chemistry, Biofilm Centre, Essen, Germany
| | - Elisabeth Girbal-Neuhauser
- Laboratoire de Biotechnologies Agroalimentaire et Environmentale (LBAE), Universite Paul Sabatier, Toulouse, France
| | - Harald Horn
- Karlsruhe Institute of Technology (KIT), Engler-Bunte-Institut, Water Chemistry and Water Technology and DVGW Research Laboratories, Karlsruhe, Germany
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore
| | | | - Tommaso Lotti
- Department of Civil and Environmental Engineering - DICEA, University of Florence, Florence, Italy
| | - M Francesca Malpei
- Dipartimento di Ingegneria Civile e Ambientale, Politecnico di Milano, Milan, Italy
| | - Robert Nerenberg
- Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, USA
| | - Thomas R Neu
- Department of River Ecology, Helmholtz Centre for Environmental Research - UFZ, Magdeburg, Germany
| | - Etienne Paul
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés, Université de Toulouse, Toulouse, France
| | - Hanqing Yu
- Department of Chemistry, University of Science and Technology of China, Hefei, China
| | - Yuemei Lin
- Department of Biotechcnology, Delft University of Technology, Delft, the Netherlands.
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16
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Zhou C, Chia GWN, Ho JCS, Seviour T, Sailov T, Liedberg B, Kjelleberg S, Hinks J, Bazan GC. Informed Molecular Design of Conjugated Oligoelectrolytes To Increase Cell Affinity and Antimicrobial Activity. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201803103] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Cheng Zhou
- School of Chemical and Biomedical Engineering Singapore
| | - Geraldine W. N. Chia
- Interdisciplinary Graduate School Singapore
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - James C. S. Ho
- Centre for Biomimetic Sensor ScienceSchool of Materials Science & EngineeringNanyang Technological University (NTU) Singapore 639798 Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - Talgat Sailov
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - Bo Liedberg
- Interdisciplinary Graduate School Singapore
- Centre for Biomimetic Sensor ScienceSchool of Materials Science & EngineeringNanyang Technological University (NTU) Singapore 639798 Singapore
| | - Staffan Kjelleberg
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - Jamie Hinks
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
| | - Guillermo C. Bazan
- School of Chemical and Biomedical Engineering Singapore
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE) Singapore
- Center for Polymers and Organic SolidsDepartments of Chemistry & Biochemistry and MaterialsUniversity of California, Santa Barbara Santa Barbara CA 93106 USA
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17
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Zhou C, Chia GWN, Ho JCS, Seviour T, Sailov T, Liedberg B, Kjelleberg S, Hinks J, Bazan GC. Informed Molecular Design of Conjugated Oligoelectrolytes To Increase Cell Affinity and Antimicrobial Activity. Angew Chem Int Ed Engl 2018; 57:8069-8072. [PMID: 29707869 DOI: 10.1002/anie.201803103] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 04/27/2018] [Indexed: 12/21/2022]
Abstract
Membrane-intercalating conjugated oligoelectrolytes (COEs) are emerging as potential alternatives to conventional, yet increasingly ineffective, antibiotics. Three readily accessible COEs, belonging to an unreported series containing a stilbene core, namely D4, D6, and D8, were designed and synthesized so that the hydrophobicity increases with increasing side-chain length. Decreased aqueous solubility correlates with increased uptake by E. coli. The minimum inhibitory concentration (MIC) of D8 is 4 μg mL-1 against both E. coli and E. faecalis, with an effective uptake of 72 %. In contrast, the MIC value of the shortest COE, D4, is 128 μg mL-1 owing to the low cellular uptake of 3 %. These findings demonstrate the application of rational design to generate efficacious antimicrobial COEs that have potential as low-cost antimicrobial agents.
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Affiliation(s)
- Cheng Zhou
- School of Chemical and Biomedical Engineering, Singapore
| | - Geraldine W N Chia
- Interdisciplinary Graduate School, Singapore.,Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - James C S Ho
- Centre for Biomimetic Sensor Science, School of Materials Science & Engineering, Nanyang Technological University (NTU), Singapore, 639798, Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - Talgat Sailov
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - Bo Liedberg
- Interdisciplinary Graduate School, Singapore.,Centre for Biomimetic Sensor Science, School of Materials Science & Engineering, Nanyang Technological University (NTU), Singapore, 639798, Singapore
| | - Staffan Kjelleberg
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - Jamie Hinks
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore
| | - Guillermo C Bazan
- School of Chemical and Biomedical Engineering, Singapore.,Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore.,Center for Polymers and Organic Solids, Departments of Chemistry & Biochemistry and Materials, University of California, Santa Barbara, Santa Barbara, CA, 93106, USA
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18
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Cruz H, Luckman P, Seviour T, Verstraete W, Laycock B, Pikaar I. Rapid removal of ammonium from domestic wastewater using polymer hydrogels. Sci Rep 2018; 8:2912. [PMID: 29440745 PMCID: PMC5811486 DOI: 10.1038/s41598-018-21204-4] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 01/31/2018] [Indexed: 11/23/2022] Open
Abstract
To date, technologies to recover ammonium from domestic wastewater from the mainstream have not found widespread application. This is largely due to the low ammonium concentrations in these wastewater streams. This paper reports on the use of polymer hydrogels for rapid sorption of ammonium from domestic wastewater coupled with efficient regeneration by mild acid washing. The sorption capacity of the hydrogel was 8.8–32.2 mg NH4–N/g, which corresponds to removal efficiencies ranging from 68% to 80% NH4–N, increasing proportionally with the initial ammonium concentration. It was, however, unaffected by changes in pH, as the sorption capacity remained constant from pH 5.0–8.0. Importantly, effective regeneration of the hydrogels under mildly acidic conditions (i.e. pH 4.0) was demonstrated with minimal loss in sorption performance following multiple sorption/desorption cycles. Overall, this study highlights the potential of low-cost polymer hydrogels for achieving mainstream ammonium recovery from domestic wastewater.
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Affiliation(s)
- Heidy Cruz
- School of Civil Engineering, The University of Queensland, QLD, 4072, Australia
| | - Paul Luckman
- School of Chemical Engineering, The University of Queensland, QLD, 4072, Australia
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore, Singapore
| | - Willy Verstraete
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Gent, Belgium
| | - Bronwyn Laycock
- School of Chemical Engineering, The University of Queensland, QLD, 4072, Australia
| | - Ilje Pikaar
- School of Civil Engineering, The University of Queensland, QLD, 4072, Australia. .,Advanced Water Management Centre (AWMC), The University of Queensland, QLD, 4072, Australia.
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19
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Limwongyut J, Liu Y, Chilambi GS, Seviour T, Hinks J, Mu Y, Bazan GC. Interactions of a paracyclophane-based conjugated oligoelectrolyte with biological membranes. RSC Adv 2018; 8:39849-39853. [PMID: 35558200 PMCID: PMC9091243 DOI: 10.1039/c8ra08069k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 11/14/2018] [Indexed: 11/21/2022] Open
Abstract
We report a non-planar conjugated oligoelectrolyte as a membrane permeabilizing material and its membrane interactions compared to the linear analog.
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Affiliation(s)
- Jakkarin Limwongyut
- Center for Polymers and Organic Solids
- Department of Chemistry and Biochemistry
- University of California
- Santa Barbara
- USA
| | - Yang Liu
- School of Biological Sciences
- Nanyang Technological University
- Singapore
| | - Gayatri Shankar Chilambi
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- Nanyang Technological University
- Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- Nanyang Technological University
- Singapore
| | - Jamie Hinks
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- Nanyang Technological University
- Singapore
| | - Yuguang Mu
- School of Biological Sciences
- Nanyang Technological University
- Singapore
| | - Guillermo C. Bazan
- Center for Polymers and Organic Solids
- Department of Chemistry and Biochemistry
- University of California
- Santa Barbara
- USA
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20
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Kundukad B, Schussman M, Yang K, Seviour T, Yang L, Rice SA, Kjelleberg S, Doyle PS. Mechanistic action of weak acid drugs on biofilms. Sci Rep 2017; 7:4783. [PMID: 28684849 PMCID: PMC5500524 DOI: 10.1038/s41598-017-05178-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/24/2017] [Indexed: 01/18/2023] Open
Abstract
Selective permeability of a biofilm matrix to some drugs has resulted in the development of drug tolerant bacteria. Here we studied the efficacy of a weak organic acid drug, N-acetyl-L-cysteine (NAC), on the eradication of biofilms formed by the mucoid strain of Pseudomonas aeruginosa and investigated the commonality of this drug with that of acetic acid. We showed that NAC and acetic acid at pH < pKa can penetrate the matrix and eventually kill 100% of the bacteria embedded in the biofilm. Once the bacteria are killed, the microcolonies swell in size and passively shed bacteria, suggesting that the bacteria act as crosslinkers within the extracellular matrix. Despite shedding of the bacteria, the remnant matrix remains intact and behaves as a pH-responsive hydrogel. These studies not only have implications for drug design but also offer a route to generate robust soft matter materials.
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Affiliation(s)
- Binu Kundukad
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore, Singapore
| | - Megan Schussman
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA
| | - Kaiyuan Yang
- Department of Pharmacy, National University of Singapore, Singapore, Singapore
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Scott A Rice
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- Centre for Marine Bio-Innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW, Australia
| | - Patrick S Doyle
- BioSystems and Micromechanics (BioSyM) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore, Singapore.
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139, USA.
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21
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Yung PY, Lo Grasso L, Mohidin AF, Acerbi E, Hinks J, Seviour T, Marsili E, Lauro FM. Erratum: Global transcriptomic responses of Escherichia coli K-12 to volatile organic compounds. Sci Rep 2017; 7:33108. [PMID: 28382940 PMCID: PMC5382579 DOI: 10.1038/srep33108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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22
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Santoro C, Mohidin AF, Grasso LL, Seviour T, Palanisamy K, Hinks J, Lauro FM, Marsili E. Sub-toxic concentrations of volatile organic compounds inhibit extracellular respiration of Escherichia coli cells grown in anodic bioelectrochemical systems. Bioelectrochemistry 2016; 112:173-7. [DOI: 10.1016/j.bioelechem.2016.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/10/2016] [Accepted: 02/17/2016] [Indexed: 12/17/2022]
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23
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Stenvang M, Dueholm MS, Vad BS, Seviour T, Zeng G, Geifman-Shochat S, Søndergaard MT, Christiansen G, Meyer RL, Kjelleberg S, Nielsen PH, Otzen DE. Epigallocatechin Gallate Remodels Overexpressed Functional Amyloids in Pseudomonas aeruginosa and Increases Biofilm Susceptibility to Antibiotic Treatment. J Biol Chem 2016; 291:26540-26553. [PMID: 27784787 DOI: 10.1074/jbc.m116.739953] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 10/07/2016] [Indexed: 01/09/2023] Open
Abstract
Epigallocatechin-3-gallate (EGCG) is the major polyphenol in green tea. It has antimicrobial properties and disrupts the ordered structure of amyloid fibrils involved in human disease. The antimicrobial effect of EGCG against the opportunistic pathogen Pseudomonas aeruginosa has been shown to involve disruption of quorum sensing (QS). Functional amyloid fibrils in P. aeruginosa (Fap) are able to bind and retain quorum-sensing molecules, suggesting that EGCG interferes with QS through structural remodeling of amyloid fibrils. Here we show that EGCG inhibits the ability of Fap to form fibrils; instead, EGCG stabilizes protein oligomers. Existing fibrils are remodeled by EGCG into non-amyloid aggregates. This fibril remodeling increases the binding of pyocyanin, demonstrating a mechanism by which EGCG can affect the QS function of functional amyloid. EGCG reduced the amyloid-specific fluorescent thioflavin T signal in P. aeruginosa biofilms at concentrations known to exert an antimicrobial effect. Nanoindentation studies showed that EGCG reduced the stiffness of biofilm containing Fap fibrils but not in biofilm with little Fap. In a combination treatment with EGCG and tobramycin, EGCG had a moderate effect on the minimum bactericidal eradication concentration against wild-type P. aeruginosa biofilms, whereas EGCG had a more pronounced effect when Fap was overexpressed. Our results provide a direct molecular explanation for the ability of EGCG to disrupt P. aeruginosa QS and modify its biofilm and strengthens the case for EGCG as a candidate in multidrug treatment of persistent biofilm infections.
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Affiliation(s)
- Marcel Stenvang
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN).,the Sino-Danish Centre for Education and Research (SDC), 8000 Aarhus C, Denmark
| | - Morten S Dueholm
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | - Brian S Vad
- From the Interdisciplinary Nanoscience Center (iNANO).,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
| | - Thomas Seviour
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | | | - Susana Geifman-Shochat
- the School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore, and
| | - Mads T Søndergaard
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark
| | | | - Rikke Louise Meyer
- From the Interdisciplinary Nanoscience Center (iNANO).,the Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| | - Staffan Kjelleberg
- the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore.,the Centre for Marine Bio-innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Mosman, New South Wales 2088, Australia
| | - Per Halkjær Nielsen
- the Center for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, 9000 Aalborg, Denmark.,the Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Singapore 637551, Singapore
| | - Daniel E Otzen
- From the Interdisciplinary Nanoscience Center (iNANO), .,Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN)
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24
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Kundukad B, Seviour T, Liang Y, Rice SA, Kjelleberg S, Doyle PS. Mechanical properties of the superficial biofilm layer determine the architecture of biofilms. Soft Matter 2016; 12:5718-26. [PMID: 27273453 DOI: 10.1039/c6sm00687f] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Cells in biofilms sense and interact with their environment through the extracellular matrix. The physicochemical properties of the matrix, particularly at the biofilm-environment interface, determine how cells respond to changing conditions. In this study we describe the application of atomic force microscopy and confocal imaging to probe in situ the mechanical properties of these interfacial regions and to elucidate how key matrix components can contribute to the physical sensing by the cells. We describe how the Young's modulus of microcolonies differs according to the size and morphology of microcolonies, as well as the flow rate. The Young's modulus increased as a function of microcolony diameter, which was correlated with the production of the polysaccharide Psl at later stages of maturation for hemispherical or mushroom shaped microcolonies. The Young's modulus of the periphery of the biofilm colony was however independent of the hydrodynamic shear. The morphology of the microcolonies also influenced interfacial or peripheral stiffness. Microcolonies with a diffuse morphology had a lower Young's modulus than isolated, circular ones and this phenomenon was due to a deficiency of Psl. In this way, changes in the specific polysaccharide components imbue the biofilm with distinct physical properties that may modulate the way in which bacteria perceive or respond to their environment. Further, the physical properties of the polysaccharides are closely linked to the specific architectures formed by the developing biofilm.
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Affiliation(s)
- Binu Kundukad
- BioSystems and Micromechanics (BioSym) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
| | - Yang Liang
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore and School of Biological Sciences, Nanyang Technological University, Singapore
| | - Scott A Rice
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore and School of Biological Sciences, Nanyang Technological University, Singapore and Centre for Marine Bio-Innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW, Australia
| | - Staffan Kjelleberg
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore and School of Biological Sciences, Nanyang Technological University, Singapore and Centre for Marine Bio-Innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Sydney, NSW, Australia
| | - Patrick S Doyle
- BioSystems and Micromechanics (BioSym) IRG, Singapore MIT Alliance for Research and Technology (SMART), Singapore and Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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25
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Yung PY, Grasso LL, Mohidin AF, Acerbi E, Hinks J, Seviour T, Marsili E, Lauro FM. Global transcriptomic responses of Escherichia coli K-12 to volatile organic compounds. Sci Rep 2016; 6:19899. [PMID: 26818886 PMCID: PMC4730218 DOI: 10.1038/srep19899] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/21/2015] [Indexed: 12/16/2022] Open
Abstract
Volatile organic compounds (VOCs) are commonly used as solvents in various industrial settings. Many of them present a challenge to receiving environments, due to their toxicity and low bioavailability for degradation. Microorganisms are capable of sensing and responding to their surroundings and this makes them ideal detectors for toxic compounds. This study investigates the global transcriptomic responses of Escherichia coli K-12 to selected VOCs at sub-toxic levels. Cells grown in the presence of VOCs were harvested during exponential growth, followed by whole transcriptome shotgun sequencing (RNAseq). The analysis of the data revealed both shared and unique genetic responses compared to cells without exposure to VOCs. Results suggest that various functional gene categories, for example, those relating to Fe/S cluster biogenesis, oxidative stress responses and transport proteins, are responsive to selected VOCs in E. coli. The differential expression (DE) of genes was validated using GFP-promoter fusion assays. A variety of genes were differentially expressed even at non-inhibitory concentrations and when the cells are at their balanced-growth. Some of these genes belong to generic stress response and others could be specific to VOCs. Such candidate genes and their regulatory elements could be used as the basis for designing biosensors for selected VOCs.
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Affiliation(s)
- Pui Yi Yung
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE). 60 Nanyang Drive, SBS-01N-27, Singapore 637551
| | - Letizia Lo Grasso
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE). 60 Nanyang Drive, SBS-01N-27, Singapore 637551
| | - Abeed Fatima Mohidin
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE). 60 Nanyang Drive, SBS-01N-27, Singapore 637551
| | - Enzo Acerbi
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE). 60 Nanyang Drive, SBS-01N-27, Singapore 637551
| | - Jamie Hinks
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE). 60 Nanyang Drive, SBS-01N-27, Singapore 637551
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE). 60 Nanyang Drive, SBS-01N-27, Singapore 637551
| | - Enrico Marsili
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE). 60 Nanyang Drive, SBS-01N-27, Singapore 637551.,School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.,School of Biotechnology, Dublin City University, Collins Avenue, Dublin 9, Ireland
| | - Federico M Lauro
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE). 60 Nanyang Drive, SBS-01N-27, Singapore 637551.,Asian School of the Environment, Nanyang Technological University, 50 Nanyang Avenue, N2-01C-45, Singapore 639798
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26
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Kim JY, Sahu S, Yau YH, Wang X, Shochat SG, Nielsen PH, Dueholm MS, Otzen DE, Lee J, Delos Santos MMS, Yam JKH, Kang NY, Park SJ, Kwon H, Seviour T, Yang L, Givskov M, Chang YT. Detection of Pathogenic Biofilms with Bacterial Amyloid Targeting Fluorescent Probe, CDy11. J Am Chem Soc 2016; 138:402-7. [DOI: 10.1021/jacs.5b11357] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Jun-Young Kim
- Department of Chemistry & Med Chem Program, Life Sciences Institute, National University of Singapore, 3 Science Drive 3, 117543, Singapore
- Singapore
Centre on Environmental Life Science Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, 11 Biopolis Way, # 02-02 Helios, 138667, Singapore
| | - Srikanta Sahu
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, 11 Biopolis Way, # 02-02 Helios, 138667, Singapore
| | - Yin-Hoe Yau
- School
of Biological Sciences, Nanyang Technological University, SBS-04s-43,
60 Nanyang Avenue, 637551, Singapore
| | - Xu Wang
- Department of Chemistry & Med Chem Program, Life Sciences Institute, National University of Singapore, 3 Science Drive 3, 117543, Singapore
| | - Susana Geifman Shochat
- School
of Biological Sciences, Nanyang Technological University, SBS-04s-43,
60 Nanyang Avenue, 637551, Singapore
| | - Per Halkjær Nielsen
- Singapore
Centre on Environmental Life Science Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
- Center
for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
| | - Morten Simonsen Dueholm
- Center
for Microbial Communities, Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
| | - Daniel E. Otzen
- Interdisciplinary
Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Jungyeol Lee
- Department of Chemistry & Med Chem Program, Life Sciences Institute, National University of Singapore, 3 Science Drive 3, 117543, Singapore
| | | | - Joey Kuok Hoong Yam
- Singapore
Centre on Environmental Life Science Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
- Interdisciplinary
Graduate School, Nanyang Technological University, 637551, Singapore
| | - Nam-Young Kang
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, 11 Biopolis Way, # 02-02 Helios, 138667, Singapore
| | - Sung-Jin Park
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, 11 Biopolis Way, # 02-02 Helios, 138667, Singapore
| | - Hawyoung Kwon
- Department of Chemistry & Med Chem Program, Life Sciences Institute, National University of Singapore, 3 Science Drive 3, 117543, Singapore
- Singapore
Centre on Environmental Life Science Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
| | - Thomas Seviour
- Singapore
Centre on Environmental Life Science Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
| | - Liang Yang
- Singapore
Centre on Environmental Life Science Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
- School
of Biological Sciences, Nanyang Technological University, SBS-04s-43,
60 Nanyang Avenue, 637551, Singapore
| | - Michael Givskov
- Singapore
Centre on Environmental Life Science Engineering (SCELSE), Nanyang Technological University, 637551, Singapore
- Costerton
Biofilm Center, Department of Immunology and Microbiology, Faculty
of Health and Medical Sciences, University of Copenhagen, Blegdamsvej
3B, DK-2200 Copenhagen, Denmark
| | - Young-Tae Chang
- Department of Chemistry & Med Chem Program, Life Sciences Institute, National University of Singapore, 3 Science Drive 3, 117543, Singapore
- Singapore Bioimaging Consortium, Agency for Science, Technology and Research, 11 Biopolis Way, # 02-02 Helios, 138667, Singapore
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27
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Xie WM, Ni BJ, Sheng GP, Seviour T, Yu HQ. Quantification and kinetic characterization of soluble microbial products from municipal wastewater treatment plants. Water Res 2016; 88:703-710. [PMID: 26580086 DOI: 10.1016/j.watres.2015.10.065] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 10/28/2015] [Accepted: 10/30/2015] [Indexed: 06/05/2023]
Abstract
Soluble microbial products (SMP) formed by microorganisms in wastewater treatment plants (WWTPs) adversely affect final effluent quality and treatment efficiency. It is difficult to distinguish SMP from residual proteins, lipids and carbohydrates present in the influent that may persist during treatment. No method is currently available to determine quantitatively the extent to which SMP contribute to organic discharges from municipal WWTPs. In this work a modeling approach is presented which allows the SMP fraction of the effluent of a municipal WWTP to be quantified and described. The model is validated, in terms of utilization-associated products, biomass-associated products and extracellular polymeric substances, using influent from a municipal WWTP. SMP was found to account for, on average, 27 mg/L of chemical oxygen demand (COD), or 61% of the total COD in the WWTP effluent. Over 90% of the SMP was comprised of biomass-associated products. Five main factors influencing SMP formation in WWTP were evaluated. Neither wastewater composition nor mixed liquor suspended solids concentration was found to affect SMP production. On the other hand, a positive correlation was observed for SMP formation with both solids retention time and influent COD concentration, and a negative correlation with hydraulic retention time. Thus, operating or designing WWTPs with short solids retention and long hydraulic retention times could be considered as solutions for minimizing SMP production.
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Affiliation(s)
- Wen-Ming Xie
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026 China
| | - Bing-Jie Ni
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026 China
| | - Guo-Ping Sheng
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026 China
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, School of Biological Sciences, 637551 Singapore.
| | - Han-Qing Yu
- CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science & Technology of China, Hefei, 230026 China.
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28
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Hinks J, Wang Y, Matysik A, Kraut R, Kjelleberg S, Mu Y, Bazan GC, Wuertz S, Seviour T. Increased Microbial Butanol Tolerance by Exogenous Membrane Insertion Molecules. ChemSusChem 2015; 8:3718-3726. [PMID: 26404512 DOI: 10.1002/cssc.201500194] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 07/13/2015] [Indexed: 06/05/2023]
Abstract
Butanol is an ideal biofuel, although poor titers lead to high recovery costs by distillation. Fluidization of microbial membranes by butanol is one of the major factors limiting titers in butanol-producing bioprocesses. Starting with the hypothesis that certain membrane insertion molecules would stabilize the lipid bilayer in the presence of butanol, we applied a combination of in vivo and in vitro techniques within an in silico framework to describe a new approach to achieve solvent tolerance in bacteria. Single-molecule tracking of a model supported bilayer showed that COE1-5C, a five-ringed oligo-polyphenylenevinylene conjugated oligoelectrolyte (COE), reduced the diffusion rate of phospholipids in a microbially derived lipid bilayer to a greater extent than three-ringed and four-ringed COEs. Furthermore, COE1-5C treatment increased the specific growth rate of E. coli K12 relative to a control at inhibitory butanol concentrations. Consequently, to confer butanol tolerance to microbes by exogenous means is complementary to genetic modification of strains in industrial bioprocesses, extends the physiological range of microbes to match favorable bioprocess conditions, and is amenable with complex and undefined microbial consortia for biobutanol production. Molecular dynamics simulations indicated that the π-conjugated aromatic backbone of COE1-5C likely acts as a hydrophobic tether for glycerophospholipid acyl chains by enhancing bilayer integrity in the presence of high butanol concentrations, which thereby counters membrane fluidization. COE1-5C-mitigated E. coli K12 membrane depolarization by butanol is consistent with the hypothesis that improved growth rates in the presence of butanol are a consequence of improved bilayer stability.
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Affiliation(s)
- Jamie Hinks
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 637551, Singapore.
| | - Yaofeng Wang
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Artur Matysik
- Division of Molecular Genetics and Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Rachel Kraut
- Division of Molecular Genetics and Cell Biology, School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Staffan Kjelleberg
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 637551, Singapore
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
- Centre for Marine BioInnovation and School of Biotechnology and Bimolecular Sciences, University of New South Wales, Sydney, 2052, Australia
| | - Yuguang Mu
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Guillermo C Bazan
- Department of Chemistry & Biochemistry and Materials, Center for Polymers and Organic Solids, University of California, Santa Barbara, California, 93106, USA
| | - Stefan Wuertz
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 637551, Singapore
- Department of Civil and Environmental Engineering, University of California, Davis, California, 95616, USA
| | - Thomas Seviour
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, 637551, Singapore.
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29
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Seviour T, Hansen SH, Yang L, Yau YH, Wang VB, Stenvang MR, Christiansen G, Marsili E, Givskov M, Chen Y, Otzen DE, Nielsen PH, Geifman-Shochat S, Kjelleberg S, Dueholm MS. Functional amyloids keep quorum-sensing molecules in check. J Biol Chem 2015; 290:6457-69. [PMID: 25586180 DOI: 10.1074/jbc.m114.613810] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The mechanism by which extracellular metabolites, including redox mediators and quorum-sensing signaling molecules, traffic through the extracellular matrix of biofilms is poorly explored. We hypothesize that functional amyloids, abundant in natural biofilms and possessing hydrophobic domains, retain these metabolites. Using surface plasmon resonance, we demonstrate that the quorum-sensing (QS) molecules, 2-heptyl-3-hydroxy-4(1H)-quinolone and N-(3-oxododecanoyl)-l-homoserine lactone, and the redox mediator pyocyanin bind with transient affinity to functional amyloids from Pseudomonas (Fap). Their high hydrophobicity predisposes them to signal-amyloid interactions, but specific interactions also play a role. Transient interactions allow for rapid association and dissociation kinetics, which make the QS molecules bioavailable and at the same time secure within the extracellular matrix as a consequence of serial bindings. Retention of the QS molecules was confirmed using Pseudomonas aeruginosa PAO1-based 2-heptyl-3-hydroxy-4(1H)-quinolone and N-(3-oxododecanoyl)-l-homoserine lactone reporter assays, showing that Fap fibrils pretreated with the QS molecules activate the reporters even after sequential washes. Pyocyanin retention was validated by electrochemical analysis of pyocyanin-pretreated Fap fibrils subjected to the same washing process. Results suggest that QS molecule-amyloid interactions are probably important in the turbulent environments commonly encountered in natural habitats.
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Affiliation(s)
- Thomas Seviour
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and
| | - Susan Hove Hansen
- the Center for Microbial Communities, Aalborg University, 9220 Aalborg East, Denmark
| | - Liang Yang
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and
| | - Yin Hoe Yau
- the School of Biological Sciences (SBS), Nanyang Technological University, Singapore 637551, Singapore
| | - Victor Bochuan Wang
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the School of Materials Science and Engineering (MSE), Nanyang Technological University, Singapore 639798
| | - Marcel R Stenvang
- the Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN), and
| | - Gunna Christiansen
- the Department of Biomedicine, Aarhus University, 8000 Aarhus C, Denmark
| | - Enrico Marsili
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and
| | - Michael Givskov
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Department of International Health, Immunology and Microbiology, University of Copenhagen, 1165 Copenhagen, Denmark, and
| | - Yicai Chen
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and
| | - Daniel E Otzen
- the Interdisciplinary Nanoscience Center (iNANO), Department of Molecular Biology and Genetics, Center for Insoluble Protein Structures (inSPIN), and
| | - Per Halkjær Nielsen
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Center for Microbial Communities, Aalborg University, 9220 Aalborg East, Denmark
| | - Susana Geifman-Shochat
- the School of Biological Sciences (SBS), Nanyang Technological University, Singapore 637551, Singapore
| | - Staffan Kjelleberg
- From the Singapore Centre on Environmental Life Sciences Engineering (SCELSE) and the Centre for Marine Bio-innovation and School of Biotechnology and Biomolecular Science, University of New South Wales, Mosman, New South Wales 2088, Australia
| | - Morten S Dueholm
- the Center for Microbial Communities, Aalborg University, 9220 Aalborg East, Denmark
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30
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Seviour T, Doyle LE, Lauw SJL, Hinks J, Rice SA, Nesatyy VJ, Webster RD, Kjelleberg S, Marsili E. Voltammetric profiling of redox-active metabolites expressed by Pseudomonas aeruginosa for diagnostic purposes. Chem Commun (Camb) 2015; 51:3789-92. [DOI: 10.1039/c4cc08590f] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Voltammetric analysis ofPseudomonas aeruginosagrowth cultures unveils the interplay between PQS and phenazines under a potential bias.
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Affiliation(s)
- T. Seviour
- Singapore Centre on Environmental Life Sciences Engineering
- Nanyang Technological University
- Singapore
| | - L. E. Doyle
- Singapore Centre on Environmental Life Sciences Engineering
- Nanyang Technological University
- Singapore
- Interdisciplinary Graduate School
- Nanyang Technological University
| | - S. J. L. Lauw
- School of Physical & Mathematical Sciences
- Nanyang Technological University
- Singapore
| | - J. Hinks
- Singapore Centre on Environmental Life Sciences Engineering
- Nanyang Technological University
- Singapore
| | - S. A. Rice
- Singapore Centre on Environmental Life Sciences Engineering
- Nanyang Technological University
- Singapore
| | - V. J. Nesatyy
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- National University of Singapore
- Singapore
- Singapore
| | - R. D. Webster
- School of Physical & Mathematical Sciences
- Nanyang Technological University
- Singapore
| | - S. Kjelleberg
- Singapore Centre on Environmental Life Sciences Engineering
- Nanyang Technological University
- Singapore
- School of Biotechnology and Biomolecular Sciences and Centre for Marine Bio-Innovation
- The University of New South Wales
| | - E. Marsili
- Singapore Centre on Environmental Life Sciences Engineering
- Nanyang Technological University
- Singapore
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31
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Seviour T, Weerachanchai P, Hinks J, Roizman D, Rice SA, Bai L, Lee JM, Kjelleberg S. Solvent optimization for bacterial extracellular matrices: a solution for the insoluble. RSC Adv 2015. [DOI: 10.1039/c4ra10930a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Ionic liquids enable solvent optimization for different biofilms through solubility parameter concept.
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Affiliation(s)
- Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- Nanyang Technological University
- Singapore
| | - Piyarat Weerachanchai
- Nanyang Environment and Water Research Institute (NEWRI)
- Nanyang Technological University
- Singapore
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
| | - Jamie Hinks
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- Nanyang Technological University
- Singapore
| | - Dan Roizman
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- Nanyang Technological University
- Singapore
| | - Scott A. Rice
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- Nanyang Technological University
- Singapore
- School of Biological Sciences (SBS)
- Nanyang Technological University
| | - Linlu Bai
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
- Singapore
| | - Jong-Min Lee
- School of Chemical and Biomedical Engineering
- Nanyang Technological University
- Singapore
| | - Staffan Kjelleberg
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE)
- Nanyang Technological University
- Singapore
- Centre for Marine BioInnovation and School of Biotechnology and Biomolecular Sciences
- University of New South Wales
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32
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Chew SC, Kundukad B, Seviour T, van der Maarel JRC, Yang L, Rice SA, Doyle P, Kjelleberg S. Dynamic remodeling of microbial biofilms by functionally distinct exopolysaccharides. mBio 2014; 5:e01536-14. [PMID: 25096883 PMCID: PMC4128364 DOI: 10.1128/mbio.01536-14] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/07/2014] [Indexed: 12/24/2022] Open
Abstract
Biofilms are densely populated communities of microbial cells protected and held together by a matrix of extracellular polymeric substances. The structure and rheological properties of the matrix at the microscale influence the retention and transport of molecules and cells in the biofilm, thereby dictating population and community behavior. Despite its importance, quantitative descriptions of the matrix microstructure and microrheology are limited. Here, particle-tracking microrheology in combination with genetic approaches was used to spatially and temporally study the rheological contributions of the major exopolysaccharides Pel and Psl in Pseudomonas aeruginosa biofilms. Psl increased the elasticity and effective cross-linking within the matrix, which strengthened its scaffold and appeared to facilitate the formation of microcolonies. Conversely, Pel reduced effective cross-linking within the matrix. Without Psl, the matrix becomes more viscous, which facilitates biofilm spreading. The wild-type biofilm decreased in effective cross-linking over time, which would be advantageous for the spreading and colonization of new surfaces. This suggests that there are regulatory mechanisms to control production of the exopolysaccharides that serve to remodel the matrix of developing biofilms. The exopolysaccharides were also found to have profound effects on the spatial organization and integration of P. aeruginosa in a mixed-species biofilm model of P. aeruginosa-Staphylococcus aureus. Pel was required for close association of the two species in mixed-species microcolonies. In contrast, Psl was important for P. aeruginosa to form single-species biofilms on top of S. aureus biofilms. Our results demonstrate that Pel and Psl have distinct physical properties and functional roles during biofilm formation. Importance: Most bacteria grow as biofilms in the environment or in association with eukaryotic hosts. Removal of biofilms that form on surfaces is a challenge in clinical and industrial settings. One of the defining features of a biofilm is its extracellular matrix. The matrix has a heterogeneous structure and is formed from a secretion of various biopolymers, including proteins, extracellular DNA, and polysaccharides. It is generally known to interact with biofilm cells, thus affecting cell physiology and cell-cell communication. Despite the fact that the matrix may comprise up to 90% of the biofilm dry weight, how the matrix properties affect biofilm structure, maturation, and interspecies interactions remain largely unexplored. This study reveals that bacteria can use specific extracellular polymers to modulate the physical properties of their microenvironment. This in turn impacts biofilm structure, differentiation, and interspecies interactions.
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Affiliation(s)
| | - Binu Kundukad
- BioSystems and Micromechanics IRG, Singapore-MIT Alliance for Research and Technology, National University of Singapore, Singapore
| | - Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering, Nanyang Technological University, Singapore
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33
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Hinks J, Wang Y, Poh WH, Donose BC, Thomas AW, Wuertz S, Loo SCJ, Bazan GC, Kjelleberg S, Mu Y, Seviour T. Modeling cell membrane perturbation by molecules designed for transmembrane electron transfer. Langmuir 2014; 30:2429-2440. [PMID: 24499294 DOI: 10.1021/la403409t] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Certain conjugated oligoelectrolytes (COEs) modify biological function by improving charge transfer across biological membranes as demonstrated by their ability to boost performance in bioelectrochemical systems. Molecular level understanding of the nature of the COE/membrane interactions is lacking. Thus, we investigated cell membrane perturbation by three COEs differing in the number of aromatic rings and presence of a fluorine substitution. Molecular dynamic simulations showed that membrane deformation by all COEs resulted from membrane thinning as the lipid phosphate heads were drawn toward the center of the bilayer layer by positively charged COE side chains. The four-ringed COE, which most closely resembled the lipid bilayer in length, deformed the membrane the least and was least disruptive, as supported by toxicity testing (minimum inhibitory concentration (MIC) = 64 μmol L(-1)) and atomic force microscopy (AFM). Extensive membrane thinning was observed from three-ringed COEs, reducing membrane thickness to <3.0 nm in regions where the COEs were located. Severe localized membrane pitting was observed when the central aromatic ring was unfluorinated, as evident from AFM and simulations. Fluorinating the central aromatic ring delocalized thinning but induced greater membrane disorder, indicated by changes in deuterium order parameter of the acyl chains. The fluorinated three-ringed compound was less toxic (MIC 4 μmol L(-1)) than the nonfluorinated three-aromatic-ringed COE (MIC 2 μmol L(-1)); thus, hydrophobic polar interactions resulting from fluorine substitution of OPV COEs dissipate membrane perturbations. Correlating specific structural features with cell membrane perturbation is an important step toward designing non-antimicrobial membrane insertion molecules.
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Affiliation(s)
- Jamie Hinks
- Singapore Centre on Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University , Singapore 637551
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Xie WM, Ni BJ, Seviour T, Yu HQ. Evaluating the impact of operational parameters on the formation of soluble microbial products (SMP) by activated sludge. Water Res 2013; 47:1073-1079. [PMID: 23260173 DOI: 10.1016/j.watres.2012.11.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 11/01/2012] [Accepted: 11/13/2012] [Indexed: 06/01/2023]
Abstract
Soluble microbial products (SMP) are the major component of the residual organic fraction in biological wastewater treatment effluent. The impact of process parameters on SMP production by specific groups of bacteria is currently unknown. In this work, SMP production by activated sludge at different substrate concentrations, dissolved oxygen (DO) levels and temperatures, was evaluated by experimental and modeling approaches. The results showed that among the three parameters, SMP production was most sensitive to substrate concentration. Total SMP production was increased 70.5% by a threefold increase in substrate concentration, with SMP produced from heterotrophs, ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) increasing by 61.2%, 580.0% and 410.0%, respectively. The effect of temperature on SMP was less pronounced. Decreasing the temperature from 20 °C to 10 °C decreased total SMP by 17.2%, with SMP production from heterotrophs decreasing by 20.0%, and from the AOB and NOB increasing by 180.0% and 140.0%. DO concentration had nearly no effect on total and heterotrophic SMP production, while it did have a significant positive effect on autotrophic SMP production. SMP production from AOB and NOB decreased by 24.3% and 47.8%, respectively following a decrease in DO concentration from 8.7 to 1.5 mg/L. However, the net effect of DO on total SMP production was negligible.
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Affiliation(s)
- Wen-Ming Xie
- Department of Chemistry, University of Science & Technology of China, Hefei 230026 China
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Xie WM, Ni BJ, Seviour T, Sheng GP, Yu HQ. Characterization of autotrophic and heterotrophic soluble microbial product (SMP) fractions from activated sludge. Water Res 2012; 46:6210-6217. [PMID: 22463864 DOI: 10.1016/j.watres.2012.02.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Revised: 02/24/2012] [Accepted: 02/28/2012] [Indexed: 05/31/2023]
Abstract
Soluble microbial products (SMP) generated by microbial populations can adversely affect the efficiency of biological wastewater treatment systems and secondary effluent quality. In this work, both experimental and modeling approaches were used to investigate the formation of SMP by both heterotrophic and autotrophic bacteria. Strategies to control and reduce SMP in activated sludge systems were thus evaluated. SMP produced by heterotrophs were found to account for more than 92% of total SMP. The SMP produced by autotrophs contributed to less than 8% of the total SMP, with 5% attributable to the ammonia-oxidizing bacteria (AOB) and 3% to the nitrite-oxidizing bacteria (NOB). When external organic substrate was present, the utilization-associated products (UAP) were the main component of SMP. When external organic substrate was completely consumed, biomass-associated products (BAP) from the hydrolysis of extracellular polymeric substances (EPS) dominated the SMP. The model developed in this study described the fractions and dynamics of UAP and BAP produced by heterotrophs, AOB and NOB. Solids retention time of the reactor had a significant effect on SMP production, while the effect of the hydraulic retention time was only minor. Decreasing the solids retention time from 15 to 0.5 d reduced SMP production in the reactor by 62%.
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Affiliation(s)
- Wen-Ming Xie
- Department of Chemistry, University of Science & Technology of China, Hefei 230026, China
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Seviour T, Yuan Z, van Loosdrecht MCM, Lin Y. Aerobic sludge granulation: a tale of two polysaccharides? Water Res 2012; 46:4803-4813. [PMID: 22776210 DOI: 10.1016/j.watres.2012.06.018] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Revised: 05/28/2012] [Accepted: 06/09/2012] [Indexed: 06/01/2023]
Abstract
Aerobic sludge granules are suspended biofilms with the potential to reduce the cost and footprint of secondary wastewater treatment. Attempts to answer how and why they form leads to a consideration of the role of their extracellular polymeric substances (EPS) in determining their physical and microbiological properties. The exopolysaccharide components of this matrix, in particular, have received attention as putative structural, gel-forming agents. Two quite different exopolysaccharides have been proposed as the gel-forming constituents, with their gel properties clearly different from those of activated sludge EPS. This review aims to address the question of whether more than one gel-forming exopolysaccharide exist in granules. Based on the available structural data, it seems likely that they are different gel-forming polymers and their differences are not artifacts of the analytical methods used. Nonetheless, both proposed structural gel polymers are extracted and purified based on procedures selecting for anionic polar polysaccharides soluble at high pH, and both contain hexuronic acids. Granulation does not result from EPS synthesis by any single microbial population, nor from production of a single exopolysaccharide. Future studies using solvents suitable for recalcitrant polysaccharides are likely to reveal important structural roles for other polysaccharides. It is hoped that this article will serve as a guide for subsequent studies into understanding the roles of exopolysaccharides in aerobic granular sludge.
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Affiliation(s)
- Thomas Seviour
- Singapore Centre on Environmental Life Sciences Engineering-SCELSE, Nanyang Technological University, SBS-B2n-27, 60 Nanyang Drive, Singapore 637551, Singapore.
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Seviour T, Malde AK, Kjelleberg S, Yuan Z, Mark AE. Molecular Dynamics Unlocks Atomic Level Self-Assembly of the Exopolysaccharide Matrix of Water-Treatment Granular Biofilms. Biomacromolecules 2012; 13:1965-72. [DOI: 10.1021/bm3005808] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Thomas Seviour
- Nanyang Technological University, Singapore Centre on Environmental Life Sciences
Engineering (SCELSE), Singapore 637551
- The University of Queensland, Advanced Water Management Centre (AWMC),
St. Lucia, QLD 4072, Australia
- The University of Queensland, School of Chemistry and Molecular Biosciences
(SCMB), St. Lucia, QLD 4072, Australia
| | - Alpeshkumar K. Malde
- The University of Queensland, School of Chemistry and Molecular Biosciences
(SCMB), St. Lucia, QLD 4072, Australia
| | - Staffan Kjelleberg
- Nanyang Technological University, Singapore Centre on Environmental Life Sciences
Engineering (SCELSE), Singapore 637551
| | - Zhiguo Yuan
- The University of Queensland, Advanced Water Management Centre (AWMC),
St. Lucia, QLD 4072, Australia
| | - Alan E. Mark
- The University of Queensland, School of Chemistry and Molecular Biosciences
(SCMB), St. Lucia, QLD 4072, Australia
- The University of Queensland, Institute for Molecular Bioscience (IMB),
St. Lucia, QLD 4072, Australia
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Seviour T, Lambert LK, Pijuan M, Yuan Z. Structural determination of a key exopolysaccharide in mixed culture aerobic sludge granules using NMR spectroscopy. Environ Sci Technol 2010; 44:8964-8970. [PMID: 21033741 DOI: 10.1021/es102658s] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Nuclear magnetic resonance (NMR) techniques were used to elucidate the structure of an exopolysaccharide material previously revealed to be important in formation of aerobic granules. The 1D NMR spectral data acquired showed that this gel-forming polysaccharide was a major component of granular EPS, while 1D and 2D NMR spectra showed it consisted of eight sugar residues. These were assigned as α-galactose, α-rhamnose, 2-acetoamido-2-deoxy-α-galactopyranuronic acid, β-mannose, β-galactose, β-glucuronate, β-glucosamine, and N-acetyl β-galactosamine. With the exception of 2-acetoamido-2-deoxy-α-galactopyranuronic acid, a highly unusual sugar, their presence was confirmed with high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Carbon and proton shifts were assigned for each sugar. Heteronuclear multiple bond correlation (HMBC) and nuclear Overhauser enhancement spectroscopy (NOESY) were used to identify linkage sites between individual sugar residues. This gel-forming exopolysaccharide appeared to be a highly complex single heteropolysaccharide with a repeat sequence of α-galactose, β-mannose, β-glucosamine, N-acetyl-β-galactosamine, and 2-acetoamido-2-deoxy-α-galactopyranuronic acid. It has a disaccharide branch of β-galactose and β-glucuronic acid attached to 2-acetoamido-2-deoxy-α-galactopyranuronic acid and an α-rhamnose branch attached to α-galactose.
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Affiliation(s)
- Thomas Seviour
- The University of Queensland, Advanced Water Management Centre, St. Lucia, QLD 4072, Australia
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Seviour T, Donose BC, Pijuan M, Yuan Z. Purification and conformational analysis of a key exopolysaccharide component of mixed culture aerobic sludge granules. Environ Sci Technol 2010; 44:4729-4734. [PMID: 20476734 DOI: 10.1021/es100362b] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The application of aerobic sludge granules in wastewater treatment could increase the intensity of wastewater treatment processes because of their greater density and size relative to conventional sludge flocs. It has been suggested that granules are distinguished from flocs by gel forming exopolysaccharides. In this study, evidence is presented linking a specific exopolysaccharide component with granule extracellular polymeric substance (EPS) gelation. Granular EPS comprised three components: high-molecular-weight (MW) exopolysaccharide, medium-MW proteins and glycosides, and low-MW proteins and glycosides. The high-MW fraction was separated by fractional precipitation and preparatory-scale gel permeation chromatography (GPC). The MW profile of this fraction appears to be exclusively attributable to high-MW polysaccharide. The exopolysaccharide exists as a gel at normal wastewater treatment operating pH (i.e., 6.0-8.5), whereas the low/medium-MW material does not. Conformational analysis by atomic force microscopy (AFM) of the dried material showed that the polysaccharide forms pearl-necklace-like, intramolecularly condensed structures when dissolved in Milli-Q water and partially relaxed helical aggregates when in alkali solution. Consequently, the gel-forming property of EPS in the aerobic sludge granules tested is probably associated with high-MW polysaccharide components.
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Affiliation(s)
- Thomas Seviour
- Advanced Water Management Centre and Australian National Fabrication Facility (QLD Node), Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St. Lucia QLD 4072, Australia
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Seviour T, Pijuan M, Nicholson T, Keller J, Yuan Z. Gel-forming exopolysaccharides explain basic differences between structures of aerobic sludge granules and floccular sludges. Water Res 2009; 43:4469-4478. [PMID: 19682721 DOI: 10.1016/j.watres.2009.07.018] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 07/06/2009] [Accepted: 07/11/2009] [Indexed: 05/28/2023]
Abstract
The sol-gel transition of extracellular polymeric substances (EPS) derived from sludge flocs and granules is investigated in order to explain basic differences between the two aggregates. A reversible, pH dependent sol-gel transition was observed at pH 9.0-12.0 in EPS extracted from granules. At pH <9 granule EPS existed as a strong gel, indicating that their EPS exist in a gel state at normal operating pH of a wastewater treatment system (i.e. 6.0-8.5). This characteristic transition from solution to strong gel was not observed in any of the EPS samples derived from floccular sludges. A transition to a weak gel was however, observed at pH 4.0-5.0. Enriched exopolysaccharides from the granular EPS exhibited rheological behaviour analogous to the granules and the granule EPS. The critical overlap concentration (c*) of the exopolysaccharide concentrate was 0.33% w/w, similar to the c* of other known bacterial exopolysaccharides. Additionally, the protein content was found to be not contributing to the storage modulus of granule EPS gels. These factors suggest that exopolysaccharides or glycosides were the gelling agent in aerobic sludge granules. Given that EPS derived from aerobic sludge granules and flocs are distinguished by such a sol-strong gel transition, these exopolysaccharides therefore likely play an important role in granulation.
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Affiliation(s)
- Thomas Seviour
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
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Seviour T, Pijuan M, Nicholson T, Keller J, Yuan Z. Understanding the properties of aerobic sludge granules as hydrogels. Biotechnol Bioeng 2009; 102:1483-93. [DOI: 10.1002/bit.22164] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Peters M, Newland M, Seviour T, Broom T, Bridle T. Demonstration of enhanced nutrient removal at two full-scale SBR plants. Water Sci Technol 2004; 50:115-120. [PMID: 15656303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The efficacy of sequencing batch reactors (SBRs) to provide high levels of biological nutrient removal has been extensively demonstrated around the world. Environmental Solutions International (ESI) has now constructed over 20 full-scale SBR plants and has confirmed that nutrient removal is enhanced via the process of simultaneous nitrification and denitrification. Over 18 months of operational data from two plants, operating in distinctly different catchments, processing an average of between 2,000 and 2,500 m3/d of wastewater, has clearly shown the efficacy and robustness of the ESI SBR-BNR process. Median effluent total nitrogen and total phosphorus values of 3 mg/L and <0.6 mg/L, respectively, were demonstrated over the 18-month period. This high level of nutrient removal is attributed to the design of the bio-selector which maximises carbon storage for the subsequent denitrification reactions, the effective aeration control which ensures no over-aeration during the air-on cycle as well as the level of operational control provided at these two plants.
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Affiliation(s)
- M Peters
- Environmental Solutions International Ltd, Burswood WA 6100, Australia.
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