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Shi X, Pereira R, Uzma, Savage L, Poursat B, Quinn D, Kostrytsia A, Cholet F, Smith CJ, Gauchotte-Lindsay C, Sloan WT, Ijaz UZ, Vignola M. Microbial stratification and DOM removal in drinking water biofilters: Implications for enhanced performance. WATER RESEARCH 2024; 262:122053. [PMID: 39059199 DOI: 10.1016/j.watres.2024.122053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 05/09/2024] [Accepted: 07/04/2024] [Indexed: 07/28/2024]
Abstract
Biofiltration is a low-cost, low-energy technology that employs a biologically activated bed of porous medium to reduce the biodegradable fraction of the dissolved organic matter (DOM) pool in source water, resulting in the production of drinking water. Microbial communities at different bed depths within the biofilter play crucial roles in the degradation and removal of dissolved organic carbon (DOC), ultimately impacting its performance. However, the relationships between the composition of microbial communities inhabiting different biofilter depths and their utilisation of various DOC fractions remain poorly understood. To address this knowledge gap, we conducted an experimental study where microbial communities from the upper (i.e., top 10 cm) and lower (i.e., bottom 10 cm) sections of a 30-cm long laboratory-scale biofilter were recovered. These communities were then individually incubated for 10 days using the same source water as the biofilter influent. Our study revealed that the bottom microbial community exhibited lower diversity yet had a co-occurrence network with a higher degree of interconnections among its members compared to the top microbial community. Moreover, we established a direct correlation between the composition and network structure of the microbial communities and their ability to utilise various DOM compounds within a DOM pool. Interestingly, although the bottom microbial community had only 20 % of the total cell abundance compared to the top community at the beginning of the incubation, it utilised and hence removed approximately 60 % more total DOC from the DOM pool than the top community. While both communities rapidly utilised labile carbon fractions, such as low-molecular-weight neutrals, the utilisation of more refractory carbon fractions, like high-molecular-weight humic substances with an average molecular weight of more than ca. 1451 g/mol, was exclusive to the bottom microbial community. By employing techniques that capture microbial diversity (i.e., flow cytometry and 16S rRNA amplicon sequencing) and considering the complexities of DOM (i.e., LCOCD), our study provides novel insights into how microbial community structure could influence the microbial-mediated processes of engineering significance in drinking water production. Finally, our findings could offer the opportunity to improve biofilter performances via engineering interventions that shape the compositions of biofilter microbial communities and enhance their utilisation and removal of DOM, most notably the more classically humified and refractory DOM compound groups.
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Affiliation(s)
- Xiang Shi
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Ryan Pereira
- The Lyell Centre, Heriot-Watt University, Research Avenue South, Edinburgh EH14 4AS, UK
| | - Uzma
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Laurie Savage
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Baptiste Poursat
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Dominic Quinn
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Anastasiia Kostrytsia
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Fabien Cholet
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Cindy J Smith
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Caroline Gauchotte-Lindsay
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - William T Sloan
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Umer Zeeshan Ijaz
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK
| | - Marta Vignola
- James Watt School of Engineering, Advanced Research Centre (ARC), University of Glasgow, Chapel Lane, Glasgow G11 6EW, UK.
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2
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Wang X, Li Y, Kroll A, Mitrano DM. Differentiating Microplastics from Natural Particles in Aqueous Suspensions Using Flow Cytometry with Machine Learning. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:10240-10251. [PMID: 38803057 DOI: 10.1021/acs.est.4c00304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Microplastics (MPs) in natural waters are heterogeneously mixed with other natural particles including algal cells and suspended sediments. An easy-to-use and rapid method for directly measuring and distinguishing MPs from other naturally present colloids in the environment would expedite analytical workflows. Here, we established a database of MP scattering and fluorescence properties, either alone or in mixtures with natural particles, by stain-free flow cytometry. The resulting high-dimensional data were analyzed using machine learning approaches, either unsupervised (e.g., viSNE) or supervised (e.g., random forest algorithms). We assessed our approach in identifying and quantifying model MPs of diverse sizes, morphologies, and polymer compositions in various suspensions including phototrophic microorganisms, suspended biofilms, mineral particles, and sediment. We could precisely quantify MPs in microbial phototrophs and natural sediments with high organic carbon by both machine learning models (identification accuracies over 93%), although it was not possible to distinguish between different MP sizes or polymer compositions. By testing the resulting method in environmental samples through spiking MPs into freshwater samples, we further highlight the applicability of the method to be used as a rapid screening tool for MPs. Collectively, this workflow can be easily applied to a diverse set of samples to assess the presence of MPs in a time-efficient manner.
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Affiliation(s)
- Xinjie Wang
- Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875 People's Republic of China
- Eawag-Swiss Federal Institute of Aquatic Science and Technology, 8600 Dübendorf, Switzerland
| | - Yang Li
- State Key Laboratory of Water Environment Simulation, School of Environment, Beijing Normal University, Beijing, 100875 People's Republic of China
| | - Alexandra Kroll
- Swiss Centre for Applied Ecotoxicology, 8600 Dübendorf, Switzerland
| | - Denise M Mitrano
- Department of Environmental Systems Science, ETH Zurich, 8092 Zurich, Switzerland
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Wei L, Zheng J, Han Y, Xu X, Li M, Zhu L. Insights into the roles of biochar pores toward alleviating antibiotic resistance genes accumulation in biofiltration systems. BIORESOURCE TECHNOLOGY 2024; 394:130257. [PMID: 38151208 DOI: 10.1016/j.biortech.2023.130257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/07/2023] [Accepted: 12/23/2023] [Indexed: 12/29/2023]
Abstract
Biofiltration systems would harbor and spread various antibiotic resistance genes (ARGs) when treating antibiotic micro-pollution, constituting a potential ecological risk. This study aimed to investigate the effects of biochar pores on ARG emergence and related microbial response mechanisms in bench-scale biofiltration systems. Results showed that biochar pores effectively reduced the absolute copies of the corresponding ARGs sul1 and sul2 by 54.1% by lowering the sorbed-SMX's bioavailability compared to non-porous anthracite. An investigation of antimicrobial resistomes revealed a considerable decrease in the abundance and diversity of ARGs and mobile gene elements. Metagenomic and metaproteomic analysis demonstrated that biochar pores induced the changeover of microbial defense strategy against SMX from blocking SMX uptake by EPS absorbing to SMX biotransformation. Microbial SOS response, antibiotic efflux pump, EPS secretion, and biofilm formation were decreased. Functions related to SMX biotransformation, such as sadABC-mediated transformation, xenobiotics degradation, and metabolism, were significantly promoted.
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Affiliation(s)
- Lecheng Wei
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China; Innovation Center of Yangtze River Delta, Zhejiang University, China
| | - Jingjing Zheng
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China; Innovation Center of Yangtze River Delta, Zhejiang University, China
| | - Yutong Han
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China; Innovation Center of Yangtze River Delta, Zhejiang University, China
| | - Xiangyang Xu
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China; Zhejiang Provincial Engineering Laboratory of Water Pollution Control, Hangzhou 310058, China
| | - Mengyan Li
- Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Newark, NJ, 07102, USA
| | - Liang Zhu
- Institute of Environment Pollution Control and Treatment, College of Environmental and Resource Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China; Zhejiang Provincial Engineering Laboratory of Water Pollution Control, Hangzhou 310058, China; Innovation Center of Yangtze River Delta, Zhejiang University, China.
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4
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Qin W, Xiao Q, Hong M, Yang J, Song Y, Ma J. Nano manganese dioxide coupling carbon source preloading granular activated carbon biofilter enhancing biofilm formation and pollutant removal. ENVIRONMENTAL RESEARCH 2024; 241:117606. [PMID: 37951378 DOI: 10.1016/j.envres.2023.117606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 11/02/2023] [Accepted: 11/04/2023] [Indexed: 11/14/2023]
Abstract
The formation of stable and mature biofilms affects the efficient and stable removal of ammonium by biological activated carbon (BAC). In this study, the new granular activated carbon (GAC) was preloaded with the carbon source (glucose and sucrose) and nano manganese dioxide (nMnO2) before using. Then tests were performed to determine whether substrate preloading promoted ammonium removal. The ammonium removal treated by nMnO2 coupled with sucrose-loaded BAC reached 49.1 ± 2.5%, which was 1.7 times higher than that by the nonloaded BAC 28.2 ± 1.9%). The biomass on the substrate-loaded BAC reached 5.83 × 106-1.22 × 107 cells/g DW GAC on Day 7, which was 4.6-9.5 times higher than the value of the nonloaded BAC (1.28 × 106 cells/g DW GAC). The amount of extracellular polymer (i.e., protein) on nMnO2 coupled to sucrose-loaded BAC was promoted significantly. Flavobacterium (0.7%-11%), Burkholderiaceae (13%-20%) and Aquabacterium (30%-67%) were the dominant functional bacteria on the substrate-loaded BAC, which were conducive to the nitrification or denitrification process. The results indicated that loading nMnO2 and/or a carbon source accelerated the formation of biofilms on BAC and ammonium removal. Additionally, the ammonium removal treated by nMnO2 coupled with sucrose-loaded BAC was contributed by microbial degradation (56.0 ± 2.5%), biofilm adsorption (38.7 ± 2.1%) and GAC adsorption (5.3 ± 0.3%), suggesting a major role of microbial degradation.
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Affiliation(s)
- Wen Qin
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Qiurong Xiao
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Miaoqing Hong
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Jingru Yang
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China
| | - Yang Song
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
| | - Jun Ma
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
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Winkelhorst M, Cabau-Peinado O, Straathof AJ, Jourdin L. Biomass-specific rates as key performance indicators: A nitrogen balancing method for biofilm-based electrochemical conversion. Front Bioeng Biotechnol 2023; 11:1096086. [PMID: 36741763 PMCID: PMC9892193 DOI: 10.3389/fbioe.2023.1096086] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 01/04/2023] [Indexed: 01/20/2023] Open
Abstract
Microbial electrochemical technologies (METs) employ microorganisms utilizing solid-state electrodes as either electron sink or electron source, such as in microbial electrosynthesis (MES). METs reaction rate is traditionally normalized to the electrode dimensions or to the electrolyte volume, but should also be normalized to biomass amount present in the system at any given time. In biofilm-based systems, a major challenge is to determine the biomass amount in a non-destructive manner, especially in systems operated in continuous mode and using 3D electrodes. We developed a simple method using a nitrogen balance and optical density to determine the amount of microorganisms in biofilm and in suspension at any given time. For four MES reactors converting CO2 to carboxylates, >99% of the biomass was present as biofilm after 69 days of reactor operation. After a lag phase, the biomass-specific growth rate had increased to 0.12-0.16 days-1. After 100 days of operation, growth became insignificant. Biomass-specific production rates of carboxylates varied between 0.08-0.37 molC molX -1d-1. Using biomass-specific rates, one can more effectively assess the performance of MES, identify its limitations, and compare it to other fermentation technologies.
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Sun Y, Su J, Ali A, Zhang S, Zheng Z, Min Y. Effect of fungal pellets on denitrifying bacteria at low carbon to nitrogen ratio: Nitrate removal, extracellular polymeric substances, and potential functions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157591. [PMID: 35901879 DOI: 10.1016/j.scitotenv.2022.157591] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/19/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
This research aims to elucidate the effect of fungal pellets (FP) on denitrifying bacteria regarding nitrate (NO3--N) removal, extracellular polymeric substances (EPS), and potential functions at a low carbon to nitrogen (C/N) ratio. A symbiotic system of FP and denitrifying bacteria GF2 was established. The symbiotic system showed 100% NO3--N removal efficiency (4.07 mg L-1 h-1) at 6 h and enhanced electron transfer capability at C/N = 1.5. The interactions between FP and denitrifying bacteria promoted the production of polysaccharides (PS) in EPS. Both the increased PS and the PS provided by FP as well as protein and humic acid-like substances in EPS could be consumed by denitrifying bacteria. FP acted as a protector and provided habitat and nutrients for denitrifying bacteria as well as improved the ability of carbohydrate metabolism, amino metabolism, and nitrogen metabolism of denitrifying bacteria. This study provides a new perspective on the relationship between FP and denitrifying bacteria.
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Affiliation(s)
- Yi Sun
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Amjad Ali
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Shuai Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhijie Zheng
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yitian Min
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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7
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Davenport R, Curtis‐Jackson P, Dalkmann P, Davies J, Fenner K, Hand L, McDonough K, Ott A, Ortega‐Calvo JJ, Parsons JR, Schäffer A, Sweetlove C, Trapp S, Wang N, Redman A. Scientific concepts and methods for moving persistence assessments into the 21st century. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2022; 18:1454-1487. [PMID: 34989108 PMCID: PMC9790601 DOI: 10.1002/ieam.4575] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 09/29/2021] [Accepted: 12/06/2021] [Indexed: 05/19/2023]
Abstract
The evaluation of a chemical substance's persistence is key to understanding its environmental fate, exposure concentration, and, ultimately, environmental risk. Traditional biodegradation test methods were developed many years ago for soluble, nonvolatile, single-constituent test substances, which do not represent the wide range of manufactured chemical substances. In addition, the Organisation for Economic Co-operation and Development (OECD) screening and simulation test methods do not fully reflect the environmental conditions into which substances are released and, therefore, estimates of chemical degradation half-lives can be very uncertain and may misrepresent real environmental processes. In this paper, we address the challenges and limitations facing current test methods and the scientific advances that are helping to both understand and provide solutions to them. Some of these advancements include the following: (1) robust methods that provide a deeper understanding of microbial composition, diversity, and abundance to ensure consistency and/or interpret variability between tests; (2) benchmarking tools and reference substances that aid in persistence evaluations through comparison against substances with well-quantified degradation profiles; (3) analytical methods that allow quantification for parent and metabolites at environmentally relevant concentrations, and inform on test substance bioavailability, biochemical pathways, rates of primary versus overall degradation, and rates of metabolite formation and decay; (4) modeling tools that predict the likelihood of microbial biotransformation, as well as biochemical pathways; and (5) modeling approaches that allow for derivation of more generally applicable biotransformation rate constants, by accounting for physical and/or chemical processes and test system design when evaluating test data. We also identify that, while such advancements could improve the certainty and accuracy of persistence assessments, the mechanisms and processes by which they are translated into regulatory practice and development of new OECD test guidelines need improving and accelerating. Where uncertainty remains, holistic weight of evidence approaches may be required to accurately assess the persistence of chemicals. Integr Environ Assess Manag 2022;18:1454-1487. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
| | | | - Philipp Dalkmann
- Bayer AG, Crop Science Division, Environmental SafetyMonheimGermany
| | | | - Kathrin Fenner
- Eawag, Swiss Federal Institute of Aquatic Science and TechnologyDübendorfSwitzerland
- Department of ChemistryUniversity of ZürichZürichSwitzerland
| | - Laurence Hand
- Syngenta, Product Safety, Jealott's Hill International Research CentreBracknellUK
| | | | - Amelie Ott
- School of EngineeringNewcastle UniversityNewcastle upon TyneUK
- European Centre for Ecotoxicology and Toxicology of Chemicals (ECETOC)BrusselsBelgium
| | - Jose Julio Ortega‐Calvo
- Instituto de Recursos Naturales y Agrobiología de SevillaConsejo Superior de Investigaciones CientíficasSevillaSpain
| | - John R. Parsons
- Institute for Biodiversity and Ecosystem DynamicsUniversity of AmsterdamAmsterdamThe Netherlands
| | - Andreas Schäffer
- RWTH Aachen University, Institute for Environmental ResearchAachenGermany
| | - Cyril Sweetlove
- L'Oréal Research & InnovationEnvironmental Research DepartmentAulnay‐sous‐BoisFrance
| | - Stefan Trapp
- Department of Environmental EngineeringTechnical University of DenmarkBygningstorvetLyngbyDenmark
| | - Neil Wang
- Total Marketing & ServicesParis la DéfenseFrance
| | - Aaron Redman
- ExxonMobil Petroleum and ChemicalMachelenBelgium
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Halla FF, Massawa SM, Joseph EK, Acharya K, Sabai SM, Mgana SM, Werner D. Attenuation of bacterial hazard indicators in the subsurface of an informal settlement and their application in quantitative microbial risk assessment. ENVIRONMENT INTERNATIONAL 2022; 167:107429. [PMID: 35914337 DOI: 10.1016/j.envint.2022.107429] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 07/20/2022] [Accepted: 07/21/2022] [Indexed: 06/15/2023]
Abstract
Pit latrines provide essential onsite sanitation services to over a billion people, but there are concerns about their role in infectious disease transmission, and impacts on groundwater resources. We conducted fieldwork in an informal settlement in Dar es Salaam, where cholera is endemic. We combined plate counting with portable MinION sequencing and quantitative polymerase chain reaction (qPCR) methods for characterization of bacteria in pit latrine sludge, leachate, shallow and deep groundwater resources. Pit latrine sludge was characterized by log10 marker gene concentrations per 100 mL of 11.2 ± 0.2, 9.9 ± 0.9, 6.0 ± 0.3, and 4.4 ± 0.8, for total bacteria (16S rRNA), E. coli (rodA), human-host-associated Bacteroides (HF183), and Vibrio cholerae (ompW), respectively. The ompW gene observations suggested 5 % asymptomatic Vibrio cholerae carriers amongst pit latrine users. Pit leachate percolation through one-meter-thick sand beds attenuated bacterial hazard indicators by 1 to 4 log10 units. But first-order removal rates derived from these data substantially overestimated the longer-range hazard attenuation in the sand aquifers. Cooccurrence of human sewage marker gene HF183 in all shallow groundwater samples testing positive for ompW genes demonstrated the human origin of Vibrio cholerae hazards in the subsurface. All borehole water samples tested negative for ompW and HF183 genes, but 16S rRNA gene sequencing data suggested ingress of faecal pollution into boreholes at the peak of the "long rainy season". Quantitative microbial risk assessment (QMRA) predicted a gastrointestinal disease burden of 0.05 DALY per person per year for the community, well above WHO targets of 10-4-10-6 DALY for disease related to drinking water.
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Affiliation(s)
- Franella Francos Halla
- Department of Environmental Engineering, School of Environmental Science and Technology, Ardhi University, Dar es Salaam, Tanzania
| | - Said Maneno Massawa
- Department of Environmental Engineering, School of Environmental Science and Technology, Ardhi University, Dar es Salaam, Tanzania
| | - Elihaika Kengalo Joseph
- Department of Environmental Engineering, School of Environmental Science and Technology, Ardhi University, Dar es Salaam, Tanzania
| | - Kishor Acharya
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Shadrack Mwita Sabai
- Department of Environmental Engineering, School of Environmental Science and Technology, Ardhi University, Dar es Salaam, Tanzania
| | - Shaaban Mrisho Mgana
- Department of Environmental Engineering, School of Environmental Science and Technology, Ardhi University, Dar es Salaam, Tanzania.
| | - David Werner
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
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9
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Sun Y, Su J, Ali A, Wang Z, Zhang S, Zheng Z, Min Y. Fungal-sponge composite carriers coupled with denitrification and biomineralization bacteria to remove nitrate, calcium, and cadmium in a bioreactor. BIORESOURCE TECHNOLOGY 2022; 355:127259. [PMID: 35550924 DOI: 10.1016/j.biortech.2022.127259] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/28/2022] [Accepted: 05/01/2022] [Indexed: 06/15/2023]
Abstract
The coexistence of nitrate (NO3--N) and heavy metals in the aquatic environment causes harm to both the aquatic ecosystem and human health. Here, fungal-sponge composite carriers (FSC) were assembled and immobilized with strain WZ39 in a bioreactor to remove NO3--N, Ca2+, and Cd2+. Stable bioreactor performance under heavy metal pressure was achieved. The highest removal efficiencies of NO3--N, Ca2+, and Cd2+ reached 100, 71.81, and 92.50%, respectively. Bacteria and precipitates were found in fungal mycelium and sponge. The precipitates composed of Ca3.9(Ca4.7Cd0.7)(PO4)6(OH)1.8, CaCO3, and CdCO3. Fluorescence excitation-emission matrix (EEM) and flow cytometric (FCM) analysis indicated bacteria in FSC exhibited a strong metabolic activity and high percentage of intact cells under heavy metal stress. High-throughput sequencing results showed Pseudomonas sp. WZ39 played a major role in the bioreactor. The potential functions associated with metabolism, heavy metal transfer, and biofilm formation had high relative abundance in the bioreactor.
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Affiliation(s)
- Yi Sun
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
| | - Amjad Ali
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhao Wang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Shuai Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Zhijie Zheng
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
| | - Yitian Min
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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10
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Chen WT, Chien CC, Ho WS, Ou JH, Chen SC, Kao CM. Effects of treatment processes on AOC removal and changes of bacterial diversity in a water treatment plant. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 311:114853. [PMID: 35276566 DOI: 10.1016/j.jenvman.2022.114853] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Revised: 02/27/2022] [Accepted: 03/04/2022] [Indexed: 06/14/2023]
Abstract
The effectiveness of different treatment processes on assimilable organic carbon (AOC) removal and bacterial diversity variations was evaluated in a water treatment plant. The van der Kooij technique was applied for AOC analysis and responses of bacterial communities were characterized by the metagenomics assay. Results show that the AOC concentrations were about 93, 148, 43, 51, 37, and 38 μg acetate-C/L in effluents of raw water basin, preozonation, rapid sand filtration (RSF), ozonation, biofiltration [biological activated carbon (BAC) filtration], and chlorination (clear water), respectively. Increased AOC concentrations were observed after preozonation, ozonation, and chlorination units due to the production of biodegradable organic matters after the oxidation processes. Results indicate that the oxidation processes were the main causes of AOC formation, which resulted in significant increases in AOC concentrations (18-59% increment). The AOC removal efficiencies were 47, 28, and 60% in the RSF, biofiltration, and the whole system, respectively. RSF and biofiltration were responsible for the AOC treatment and both processes played key roles in AOC removal. Thus, both RSF and biofiltration processes would contribute to AOC treatment after oxidation. Sediments from the raw water basin and filter samples from RSF and BAC units were collected and analyzed for bacterial communities. Results from scanning electron microscope analysis indicate that bacterial colonization was observed in filter materials. This indicates that the surfaces of the filter materials were beneficial to bacterial growth and AOC removal via the adsorption and biodegradation mechanisms. Next generation sequencing analyses demonstrate that water treatment processes resulted in the changes of bacterial diversity and community profiles in filters of RSF and BAC. According to the findings of bacterial composition and interactions, the dominant bacterial phyla were Proteobacteria (41% in RSF and 56% in BAC) followed by Planctomycetes and Acidobacteria in RSF and BAC systems, which might affect the AOC biodegradation efficiency. Results would be useful in developing AOC treatment and management processes in water treatment plants.
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Affiliation(s)
- W T Chen
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - C C Chien
- Graduate School of Biotechnology and Bioengineering, Yuan Ze University, Chung-Li City, Taoyuan, Taiwan
| | - W S Ho
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - J H Ou
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - S C Chen
- Department of Life Sciences, National Central University, Taoyuan, Taiwan.
| | - C M Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung, Taiwan.
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11
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Ogundero A, Vignola M, Connelly S, Sloan WT. Validating Flow Cytometry as a Method for Quantifying Bdellovibrio Predatory Bacteria and Its Prey for Microbial Ecology. Microbiol Spectr 2022; 10:e0103321. [PMID: 35196816 PMCID: PMC8865432 DOI: 10.1128/spectrum.01033-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 01/31/2022] [Indexed: 12/19/2022] Open
Abstract
Bdellovibrio bacteriovorus is a predatory, Gram-negative bacteria that feeds on many pathogenic bacteria and has been investigated as a possible solution for mitigating biofilms in different fields. The application depends on more fundamental ecological studies into the dynamics between Bdellovibrio and their prey. To do so requires an accurate, reliable, and, preferably rapid, way of enumerating the cells. Flow cytometry (FCM) is potentially a rapid, accurate, and inexpensive tool for this, but it has yet to be validated in the enumeration of Bdellovibrio. In this study, we developed a protocol to measure the number of Bdellovibrio in samples of various densities using FCM and compared the results with those of other methods: optical density (OD), PFU assay (PFU), and quantitative PCR (qPCR). We observed a strong correlation between values obtained using FCM and PFU (ρ = 0.923) and FCM and qPCR (ρ = 0.987). Compared to optical density there was a much weaker correlation (ρ = 0.784), which was to be expected given the well-documented uncertainty in converting optical density (OD) to cell numbers. The FCM protocol was further validated by demonstrating its ability to distinguish and count mixed populations of Bdellovibrio and the prey Pseudomonas. Thus, the accuracy of FCM as well as its speed and reproducibility make it a suitable alternative for measuring Bdellovibrio cell numbers, especially where many samples are required to capture the dynamics of predator-prey interactions. IMPORTANCE The rise of antibiotic resistance and the unwanted growth of bacteria is a universally growing problem. Predatory bacteria can be used as a biological alternative to antibiotics because they grow by feeding on other bacteria. To apply this effectively requires further study and a deeper understanding of the forces that drive a prey population to elimination. Initially, such studies require more reliable methods to count these cells. Flow cytometry (FCM) is potentially a rapid, accurate, and inexpensive tool for this, but it has yet to be validated for predatory bacteria. This study develops a protocol to count the predatory bacteria Bdellovibrio bacteriovorus and its Pseudomonas prey using FCM and compare the results with those of other methods, demonstrating its ability for studies into B. bacteriovorus predation dynamics. This could lead to the use of B. bacteriovorus for killing bacterial biofilms in fields, such as drinking water and agriculture.
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Affiliation(s)
- Ayo Ogundero
- Infrastructure and Environment, School of Engineering, University of Glasgow, Glasgow, UK
| | - Marta Vignola
- Infrastructure and Environment, School of Engineering, University of Glasgow, Glasgow, UK
| | - Stephanie Connelly
- Infrastructure and Environment, School of Engineering, University of Glasgow, Glasgow, UK
| | - William T. Sloan
- Infrastructure and Environment, School of Engineering, University of Glasgow, Glasgow, UK
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12
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Pereira AC, Tenreiro A, Cunha MV. When FLOW-FISH met FACS: Combining multiparametric, dynamic approaches for microbial single-cell research in the total environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150682. [PMID: 34600998 DOI: 10.1016/j.scitotenv.2021.150682] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/22/2021] [Accepted: 09/26/2021] [Indexed: 06/13/2023]
Abstract
In environmental microbiology, the ability to assess, in a high-throughput way, single-cells within microbial communities is key to understand their heterogeneity. Fluorescence in situ hybridization (FISH) uses fluorescently labeled oligonucleotide probes to detect, identify, and quantify single cells of specific taxonomic groups. The combination of Flow Cytometry (FLOW) with FISH (FLOW-FISH) enables high-throughput quantification of complex whole cell populations, which when associated with fluorescence-activated cell sorting (FACS) enables sorting of target microorganisms. These sorted cells may be investigated in many ways, for instance opening new avenues for cytomics at a single-cell scale. In this review, an overview of FISH and FLOW methodologies is provided, addressing conventional methods, signal amplification approaches, common fluorophores for cell physiology parameters evaluation, and model variation techniques as well. The coupling of FLOW-FISH-FACS is explored in the context of different downstream applications of sorted cells. Current and emerging applications in environmental microbiology to outline the interactions and processes of complex microbial communities within soil, water, animal microbiota, polymicrobial biofilms, and food samples, are described.
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Affiliation(s)
- André C Pereira
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal; Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Ana Tenreiro
- Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Mónica V Cunha
- Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal; Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal.
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13
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Ott A, Quintela-Baluja M, Zealand AM, O'Donnell G, Haniffah MRM, Graham DW. Improved quantitative microbiome profiling for environmental antibiotic resistance surveillance. ENVIRONMENTAL MICROBIOME 2021; 16:21. [PMID: 34794510 PMCID: PMC8600772 DOI: 10.1186/s40793-021-00391-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Understanding environmental microbiomes and antibiotic resistance (AR) is hindered by over reliance on relative abundance data from next-generation sequencing. Relative data limits our ability to quantify changes in microbiomes and resistomes over space and time because sequencing depth is not considered and makes data less suitable for Quantitative Microbial Risk Assessments (QMRA), critical in quantifying environmental AR exposure and transmission risks. RESULTS Here we combine quantitative microbiome profiling (QMP; parallelization of amplicon sequencing and 16S rRNA qPCR to estimate cell counts) and absolute resistome profiling (based on high-throughput qPCR) to quantify AR along an anthropogenically impacted river. We show QMP overcomes biases caused by relative taxa abundance data and show the benefits of using unified Hill number diversities to describe environmental microbial communities. Our approach overcomes weaknesses in previous methods and shows Hill numbers are better for QMP in diversity characterisation. CONCLUSIONS Methods here can be adapted for any microbiome and resistome research question, but especially providing more quantitative data for QMRA and other environmental applications.
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Affiliation(s)
- Amelie Ott
- School of Engineering, Newcastle University, Cassie Building, Newcastle upon Tyne, NE1 7RU, UK
| | - Marcos Quintela-Baluja
- School of Engineering, Newcastle University, Cassie Building, Newcastle upon Tyne, NE1 7RU, UK
| | - Andrew M Zealand
- School of Engineering, Newcastle University, Cassie Building, Newcastle upon Tyne, NE1 7RU, UK
| | - Greg O'Donnell
- School of Engineering, Newcastle University, Cassie Building, Newcastle upon Tyne, NE1 7RU, UK
| | | | - David W Graham
- School of Engineering, Newcastle University, Cassie Building, Newcastle upon Tyne, NE1 7RU, UK.
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14
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Ospina-Betancourth C, Acharya K, Allen B, Head IM, Sanabria J, Curtis TP. Valorization of pulp and paper industry wastewater using sludge enriched with nitrogen-fixing bacteria. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2021; 93:1734-1747. [PMID: 33765365 DOI: 10.1002/wer.1561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 02/22/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
Nitrogen-fixing bacteria (NFB) can reduce nitrogen at ambient pressure and temperature. In this study, we treated effluent from a paper mill in sequencing batch reactors (SBRs) and monitored the abundance and activity of NFB with a view to producing a sludge that could work as a biofertilizer. Four reactors were inoculated with activated sludge enriched with NFB and fed with a high C/N waste (100:0.5) from a paper mill. Though the reactors were able to reduce the organic load of the wastewater by up to 89%, they did not have any nitrogen-fixing activity and showed a decrease in the putative number of NFB (quantified with qPCR). The most abundant species in the reactors treating high C/N paper mill wastewater was identified by Illumina MiSeq 16S rRNA gene amplicon sequencing as Methyloversatilis sp. (relative abundance of 4.4%). Nitrogen fixation was observed when the C/N ratio was increased by adding sucrose. We suspect that real-world biological nitrogen fixation (BNF) will only occur where there is a C/N ratio ≤100:0.07. Consequently, operators should actively avoid adding or allowing nitrogen in the waste streams if they wish to valorize their sludge and reduce running costs. PRACTITIONER POINTS: Efficient biological wastewater treatment of low nitrogen paper mill effluent was achieved without nutrient supplementation. The sludge was still capable of fixing nitrogen although this process was not observed in the wastewater treatment system. This high C/N wastewater treatment technology could be used with effluents from cassava flour, olive oil, wine and dairy industries.
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Affiliation(s)
| | - Kishor Acharya
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK
| | - Ben Allen
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK
| | - Ian M Head
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Janeth Sanabria
- Environmental Microbiology and Biotechnology Laboratory, Engineering School of Environmental & Natural Resources, Engineering Faculty, Universidad del Valle, Cali, Colombia
| | - Thomas P Curtis
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK
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15
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Qin W, Hammes F. Substrate Pre-loading Influences Initial Colonization of GAC Biofilter Biofilms. Front Microbiol 2021; 11:596156. [PMID: 33510720 PMCID: PMC7835318 DOI: 10.3389/fmicb.2020.596156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 12/11/2020] [Indexed: 12/05/2022] Open
Abstract
Microbial community composition and stability affect pollutant removal for biological/granular activated carbon (BAC/GAC) processes. Here, we pre-loaded the organic carbon substrates sucrose, lactose, and Lysogeny Broth (LB) medium onto new GAC prior to use and then tested whether this substrate pre-loading promoted development of biofilms with high coverage that remained stable for prolonged operational periods. Temporal dynamics of the biomass and microbial community on the GAC were monitored via flow cytometry (FCM) and sequencing, respectively, in both batch and continuous-flow experiments. In comparison with the non-loaded GAC (control), the initial biofilm biomass on substrate-loaded GAC was 3–114 times higher, but the initial richness was considerably lower (only accounting for 13–28% of the control). The initial community compositions were significantly different between batch and continuous-flow column experiments, even when loaded with the same substrates. In the continuous-flow column experiments, both biomass and microbial community composition became remarkably similar to the control filters after 64 days of operation. From these findings, we conclude that substrate-loaded GAC could enhance initial colonization, affecting both biomass and microbial community composition. However, the biomass and composition did not remain stable during long-term operation due to continuous dispersal and competition from influent bacteria.
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Affiliation(s)
- Wen Qin
- School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, China.,Department of Environmental Microbiology, Eawag-Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Frederik Hammes
- Department of Environmental Microbiology, Eawag-Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
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16
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Izadi P, Fontmorin JM, Lim SS, Head IM, Yu EH. Enhanced bio-production from CO 2 by microbial electrosynthesis (MES) with continuous operational mode. Faraday Discuss 2021; 230:344-359. [PMID: 34259692 DOI: 10.1039/d0fd00132e] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Technologies able to convert CO2 to various feedstocks for fuels and chemicals are emerging due to the urge of reducing greenhouse gas emissions and de-fossilizing chemical production. Microbial electrosynthesis (MES) has been shown a promising technique to synthesize organic products particularly acetate using microorganisms and electrons. However, the efficiency of the system is low. In this study, we demonstrated the simple yet efficient strategy in enhancing the efficiency of MES by applying continuous feeding regime. Compared to the fed-batch system, continuous operational mode provided better control of pH and constant medium refreshment, resulting in higher acetate production rate and more diverse bio-products, when the cathodic potential of -1.0 V Ag/AgCl and dissolved CO2 were provided. It was observed that hydraulic retention time (HRT) had a direct effect on the pattern of production, acetate production rate and coulombic efficiency. At HRT of 3 days, pH was around 5.2 and acetate was the dominant product with the highest production rate of 651.8 ± 214.2 ppm per day and a significant coulombic efficiency of 90%. However at the HRT of 7 days, pH was lower at around 4.5, and lower but stable acetate production rate of 280 ppm per day and a maximum coulombic efficiency of 80% was obtained. In addition, more diverse and longer chain products, such as butyrate, isovalerate and caproate, were detected with low concentrations only at the HRT of 7 days. Although microbial community analysis showed the change in the planktonic cells communities after switching the fed-batch mode to continuous feeding regime, Acetobacterium still remained as the responsible bacteria for CO2 reduction to acetate, dominating the cathodic biofilm.
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Affiliation(s)
- Paniz Izadi
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK.
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17
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Kurutos A, Nikodinovic-Runic J, Veselinovic A, Veselinović JB, Kamounah FS, Ilic-Tomic T. RNA-targeting low-molecular-weight fluorophores for nucleoli staining: synthesis, in silico modelling and cellular imaging. NEW J CHEM 2021. [DOI: 10.1039/d1nj01659h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Herein we present our work on the synthesis, investigation of the photophysical properties, interactions with nucleic acids, molecular docking, and imaging application of three carbocyanine dyes.
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Affiliation(s)
- Atanas Kurutos
- Institute of Organic Chemistry with Centre of Phytochemistry
- Bulgarian Academy of Sciences
- 1113 Sofia
- Bulgaria
| | | | | | - Jovana B. Veselinović
- Institute of Molecular Genetics and Genetic Engineering
- University of Belgrade
- 11000 Belgrade
- Serbia
| | - Fadhil S. Kamounah
- Department of Chemistry
- University of Copenhagen
- DK-2100 Copenhagen
- Denmark
| | - Tatjana Ilic-Tomic
- Institute of Molecular Genetics and Genetic Engineering
- University of Belgrade
- 11000 Belgrade
- Serbia
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18
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Acharya K, Halla FF, Massawa SM, Mgana SM, Komar T, Davenport RJ, Werner D. Chlorination effects on DNA based characterization of water microbiomes and implications for the interpretation of data from disinfected systems. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 276:111319. [PMID: 32889498 DOI: 10.1016/j.jenvman.2020.111319] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 08/24/2020] [Accepted: 08/26/2020] [Indexed: 06/11/2023]
Abstract
Quantitative PCR (qPCR) and next generation sequencing (NGS) are nucleic acid based microbiology techniques that provide new insights into drinking water quality, but considerable uncertainty remains around their correct interpretation. We noticed the presence of bacterial DNA from various putative pathogens, including from faecal indicator bacteria (FIB), in disinfected water, when culturable FIB were absent. To understand these observations better we studied the effect of chlorination on conventional and DNA based microbial water quality assessments. Surface water chlorination reduced plate counts for various FIB by up to >6 log units, intact cell counts by flow cytometry by 3.3 log units, and 16S rRNA gene copies by qPCR by 1.5 and 1.6 log units for total bacteria and total coliforms, respectively. Nanopore sequencing of 16S rRNA amplicons with the portable MinION device revealed the DNA from several families containing putative pathogens appeared to be more resistant than that of other bacteria to degradation by chlorine disinfection. For instance, 16S rRNA genes assigned to the Enterobacteriaceae family, members of which are mostly the target of coliform tests, increased in relative abundance from 0.001 ± 0.0002% to 0.0036 ± 0.003% after chlorine treatment. Hence, metagenomic drinking water data needs to be interpreted with caution. Plate counts and flow cytometry in combination with DNA based analysis provide more robust insight than NGS or qPCR alone.
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Affiliation(s)
- Kishor Acharya
- School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom.
| | - Franella Francos Halla
- Department of Environmental Engineering, School of Environmental Science and Technology, Ardhi University, Dar Es Salaam, Tanzania
| | - Said Maneno Massawa
- Department of Environmental Engineering, School of Environmental Science and Technology, Ardhi University, Dar Es Salaam, Tanzania
| | - Shaaban Mrisho Mgana
- Department of Environmental Engineering, School of Environmental Science and Technology, Ardhi University, Dar Es Salaam, Tanzania
| | - Tom Komar
- School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom
| | - Russell J Davenport
- School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom
| | - David Werner
- School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, United Kingdom
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19
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Izadi P, Fontmorin JM, Godain A, Yu EH, Head IM. Parameters influencing the development of highly conductive and efficient biofilm during microbial electrosynthesis: the importance of applied potential and inorganic carbon source. NPJ Biofilms Microbiomes 2020; 6:40. [PMID: 33056998 PMCID: PMC7560852 DOI: 10.1038/s41522-020-00151-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 09/21/2020] [Indexed: 01/04/2023] Open
Abstract
Cathode-driven applications of bio-electrochemical systems (BESs) have the potential to transform CO2 into value-added chemicals using microorganisms. However, their commercialisation is limited as biocathodes in BESs are characterised by slow start-up and low efficiency. Understanding biosynthesis pathways, electron transfer mechanisms and the effect of operational variables on microbial electrosynthesis (MES) is of fundamental importance to advance these applications of a system that has the capacity to convert CO2 to organics and is potentially sustainable. In this work, we demonstrate that cathodic potential and inorganic carbon source are keys for the development of a dense and conductive biofilm that ensures high efficiency in the overall system. Applying the cathodic potential of -1.0 V vs. Ag/AgCl and providing only gaseous CO2 in our system, a dense biofilm dominated by Acetobacterium (ca. 50% of biofilm) was formed. The superior biofilm density was significantly correlated with a higher production yield of organic chemicals, particularly acetate. Together, a significant decrease in the H2 evolution overpotential (by 200 mV) and abundant nifH genes within the biofilm were observed. This can only be mechanistically explained if intracellular hydrogen production with direct electron uptake from the cathode via nitrogenase within bacterial cells is occurring in addition to the commonly observed extracellular H2 production. Indeed, the enzymatic activity within the biofilm accelerated the electron transfer. This was evidenced by an increase in the coulombic efficiency (ca. 69%) and a 10-fold decrease in the charge transfer resistance. This is the first report of such a significant decrease in the charge resistance via the development of a highly conductive biofilm during MES. The results highlight the fundamental importance of maintaining a highly active autotrophic Acetobacterium population through feeding CO2 in gaseous form, which its dominance in the biocathode leads to a higher efficiency of the system.
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Affiliation(s)
- Paniz Izadi
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK
| | | | - Alexiane Godain
- School of Natural and Environmental Sciences, Newcastle upon Tyne, UK
| | - Eileen H Yu
- School of Engineering, Newcastle University, Newcastle upon Tyne, UK.
- Department of Chemical Engineering, Loughborough University, Loughborough, UK.
| | - Ian M Head
- School of Natural and Environmental Sciences, Newcastle upon Tyne, UK
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20
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Non-cytotoxic photostable monomethine cyanine platforms: Combined paradigm of nucleic acid staining and in vivo imaging. J Photochem Photobiol A Chem 2020. [DOI: 10.1016/j.jphotochem.2020.112598] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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21
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Ott A, Martin TJ, Acharya K, Lyon DY, Robinson N, Rowles B, Snape JR, Still I, Whale GF, Albright VC, Bäverbäck P, Best N, Commander R, Eickhoff C, Finn S, Hidding B, Maischak H, Sowders KA, Taruki M, Walton HE, Wennberg AC, Davenport RJ. Multi-laboratory Validation of a New Marine Biodegradation Screening Test for Chemical Persistence Assessment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:4210-4220. [PMID: 32162906 DOI: 10.1021/acs.est.9b07710] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Current biodegradation screening tests are not specifically designed for persistence assessment of chemicals, often show high inter- and intra-test variability, and often give false negative biodegradation results. Based on previous studies and recommendations, an international ring test involving 13 laboratories validated a new test method for marine biodegradation with a focus on improving the reliability of screening to determine the environmental degradation potential of chemicals. The new method incorporated increased bacterial cell concentrations to better represent the microbial diversity; a chemical is likely to be exposed in the sampled environments and ran beyond 60 days, which is the half-life threshold for chemical persistence in the marine environment. The new test provided a more reliable and less variable characterization of the biodegradation behavior of five reference chemicals (sodium benzoate, triethanolamine, 4-nitrophenol, anionic polyacrylamide, and pentachlorophenol), with respect to REACH and OSPAR persistence thresholds, than the current OECD 306 test. The proposed new method provides a cost-effective screening test for non-persistence that could streamline chemical regulation and reduce the cost and animal welfare implications of further higher tier testing.
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Affiliation(s)
- Amelie Ott
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Timothy J Martin
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Kishor Acharya
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
| | - Delina Y Lyon
- Shell Oil Company, 150 N. Dairy Ashford Rd., Houston, Texas 77079, United States
| | - Nik Robinson
- European Oilfield Specialty Chemicals Association (EOSCA), Aberdeen AB11 6YQ, United Kingdom
| | - Bob Rowles
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft NR33 0HT, United Kingdom
| | - Jason R Snape
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
- AstraZeneca Global Environment, Mereside, Alderley Park, Macclesfield, Cheshire, SK10 4TF, United Kingdom
- School of Life Sciences, University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, United Kingdom
| | - Ian Still
- European Oilfield Specialty Chemicals Association (EOSCA), Aberdeen AB11 6YQ, United Kingdom
| | - Graham F Whale
- Risk Science Team, Shell International Ltd., 4 York Road, London SE1 7NA, United Kingdom
| | - Vurtice C Albright
- Toxicology & Environmental Research & Consulting, The Dow Chemical Company, Midland, Michigan 48674, United States
| | - Petra Bäverbäck
- Schlumberger, Sandslikroken 140, Sandsli, Bergen 5254, Norway
| | - Nicola Best
- Covance CRS Research Limited, Shardlow Business Park, London Road, Derby DE72 2GD, United Kingdom
| | - Ruth Commander
- Scymaris Ltd., Brixham Laboratory, Brixham TQ5 8BA, United Kingdom
| | - Curtis Eickhoff
- Nautilus Environmental Company, Inc., Burnaby, BC V5A 4N7, Canada
| | - Sarah Finn
- National Oilwell Varco (NOV), Flotta, Stromness, Orkney, KW16 3NP, United Kingdom
| | - Björn Hidding
- BASF SE, Carl-Bosch-Straße 38, Ludwigshafen am Rhein 67056, Germany
| | - Heiko Maischak
- Noack Laboratorien GmbH, Käthe-Paulus-Straße 1, Sarstedt, Hildesheim 31157, Germany
| | - Katherine A Sowders
- Baker Hughes - Environmental Services Group, 369 Marshall Ave., Webster Groves, Missouri 63119, United States
| | - Masanori Taruki
- Chemicals Evaluation and Research Institute, Japan, Kurume (CERI Kurume), 3-2-7 Miyanojin, Kurume-shi, Fukuoka 839-0801, Japan
| | - Helen E Walton
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft NR33 0HT, United Kingdom
| | | | - Russell J Davenport
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom
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Ospina-Betancourth C, Acharya K, Allen B, Entwistle J, Head IM, Sanabria J, Curtis TP. Enrichment of Nitrogen-Fixing Bacteria in a Nitrogen-Deficient Wastewater Treatment System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3539-3548. [PMID: 32083474 DOI: 10.1021/acs.est.9b05322] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Anthropogenic nitrogen fixation is essential to sustain a global population of 7.7 billion. However, there has been a long-standing desire to find cheaper and more environmentally friendly alternatives to the Haber-Bosch process. In this study, we developed a new strategy of nitrogen fixation by enriching free-living N2-fixing bacteria (NFB) in reactors fed with low nitrogen wastewater, analogous to those usually found in certain industrial effluents such as paper mills. Our reactors fixed appreciable quantities of nitrogen with a rate of 11.8 mg N L-1 day-1. This rate is comparable to recent "breakthrough" nitrogen-fixing technologies and far higher than observed in low C/N reactors (fed with organic matter and nitrogen). NFB were quantified using quantitative polymerase chain reaction (qPCR) of the nifH (marker gene used to identify biological nitrogen fixation) and 16S rRNA genes. The nifH gene was enriched by a factor of 10 in the nitrogen-fixing reactors (compared to controls) attaining 13% of the bacterial population (1:4.2 copies of nifH to 16S rRNA). The Illumina MiSeq 16S rRNA gene amplicon sequencing of reactors showed that the microbial community was dominated (19%) by Clostridium pasteurianum. We envisage that nitrogen-enriched biomass could potentially be used as a biofertilizer and that the treated wastewater could be released to the environment with very little post-treatment.
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Affiliation(s)
| | - Kishor Acharya
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Ben Allen
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Jim Entwistle
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Ian M Head
- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
| | - Janeth Sanabria
- Environmental Microbiology and Biotechnology Laboratory, Engineering School of Environmental & Natural Resources, Engineering Faculty, Universidad del Valle, Cali 76001, Colombia
| | - Thomas P Curtis
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, U.K
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Barati rashvanlou R, Rezaee A, Farzadkia M, Gholami M, Kermani M. Effect of micro-aerobic process on improvement of anaerobic digestion sewage sludge treatment: flow cytometry and ATP assessment. RSC Adv 2020; 10:35718-35728. [PMID: 35517111 PMCID: PMC9056904 DOI: 10.1039/d0ra05540a] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/07/2020] [Indexed: 11/21/2022] Open
Abstract
Micro-aeration as a pretreatment method improves the efficiency of anaerobic digestion of municipal sewage sludge and consequently promotes the methane production. In this study, adenosine triphosphate (ATP) and flow cytometry (FCM) were employed to monitor the performance of the micro-aerobic process and investigate the survival of bacterial cells within the process. At first, the effect of air flow rate (AFR) (0.1, 0.2, 0.3 and 0.5 vvm) on hydrolysis of mixed sludge in 5 aeration cycles (20, 30, 40, 48 and 60 hours) was examined. Then, the effects of the micro aerobic process on methane (CH4) production in anaerobic digestion were surveyed. The highest VSS reduction was 30.6% and 10.4% for 40 hours in the reactor and control, respectively. Soluble COD also fluctuated between 40.87 and 65.14% in micro-aerobic conditions; the highest SCOD was achieved at the time of 40 h. Microbial activities were increased by 597%, 170% and 79.4% for 20, 30 and 40 h pretreatment with the micro-aerobic process, respectively. Apoptosis assay showed that micro-aerobic pre-treatment at 20, 30 and 40 h increased the percentage of living cells by 57.4, 62.8 and 67.9%, respectively. On the other hand, FCM results showed that the highest percentage of viable bacteria (i.e., 67.9%) was observed at 40 h pretreating which was approximately 40% higher the ones for the control. Variation in cumulative methane production shows that methane production was increased by 221% compared to anaerobic digestion (control group). Therefore, ATP and FCM can be employed as two appropriate, accurate, relatively specific indicators for monitoring the process and bacteria viability. Micro-aeration as a pretreatment method improves the efficiency of anaerobic digestion of municipal sewage sludge and consequently promotes the methane production.![]()
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Affiliation(s)
- Reza Barati rashvanlou
- Research Center for Environmental Health Technology
- Iran University of Medical Sciences
- Tehran
- Iran
- Department of Environmental Health Engineering
| | - Abbas Rezaee
- Department of Environmental Health Engineering
- Faculty of Medical Sciences
- Tarbiat Modares University
- Tehran
- Iran
| | - Mahdi Farzadkia
- Research Center for Environmental Health Technology
- Iran University of Medical Sciences
- Tehran
- Iran
- Department of Environmental Health Engineering
| | - Mitra Gholami
- Research Center for Environmental Health Technology
- Iran University of Medical Sciences
- Tehran
- Iran
- Department of Environmental Health Engineering
| | - Majid Kermani
- Research Center for Environmental Health Technology
- Iran University of Medical Sciences
- Tehran
- Iran
- Department of Environmental Health Engineering
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Abstract
The ability to quantify bacterial abundance is important for understanding the contributions of microbial communities in soils, but such assays remain difficult and time-consuming. Flow cytometry offers a fast and direct way to count bacterial cells, but several concerns remain in applying the technique to soils. This study aimed to improve the efficiency of the method for soil while quantifying its limitations. We demonstrated that an optimized procedure was sensitive enough to capture differences in bacterial abundances among treatments and ecosystems in two field studies. Bacterial abundance is a fundamental metric for understanding the population dynamics of soil bacteria and their role in biogeochemical cycles. Despite its importance, methodological constraints hamper our ability to assess bacterial abundance in terrestrial environments. Here, we aimed to optimize the use of flow cytometry (FCM) to assay bacterial abundances in soil while providing a rigorous quantification of its limitations. Soil samples were spiked with Escherichia coli to evaluate the levels of recovery efficiency among three extraction approaches. The optimized method added a surfactant (a tetrasodium pyrophosphate [TSP] buffer) to 0.1 g of soil, applied an intermediate degree of agitation through shaking, and used a Nycodenz density gradient to separate the cells from background debris. This procedure resulted in a high (average, 89%) level of cell recovery. Recovery efficiencies did not differ significantly among sites across an elevation gradient but were positively correlated with percent carbon in the soil samples. Estimated abundances were also highly repeatable between technical replicates. The method was applied to samples from two field studies and, in both cases, was sensitive enough to detect treatment and site differences in bacterial abundances. We conclude that FCM offers a fast and sensitive method to assay soil bacterial abundance from relatively small amounts of soil. Further work is needed to assay differential biases of the method across a wider range of soil types. IMPORTANCE The ability to quantify bacterial abundance is important for understanding the contributions of microbial communities in soils, but such assays remain difficult and time-consuming. Flow cytometry offers a fast and direct way to count bacterial cells, but several concerns remain in applying the technique to soils. This study aimed to improve the efficiency of the method for soil while quantifying its limitations. We demonstrated that an optimized procedure was sensitive enough to capture differences in bacterial abundances among treatments and ecosystems in two field studies.
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Dong X, Bäcker LE, Rahmatullah M, Schunk D, Lens G, Meckenstock RU. Quantification of microbial degradation activities in biological activated carbon filters by reverse stable isotope labelling. AMB Express 2019; 9:109. [PMID: 31312915 PMCID: PMC6635546 DOI: 10.1186/s13568-019-0827-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 06/29/2019] [Indexed: 11/10/2022] Open
Abstract
Biological activated carbon (BAC) filters are frequently used in drinking water production for removing dissolved organic carbon (DOC) via adsorption of organic compounds and microbial degradation. However, proper methods are still missing to distinguish the two processes. Here, we introduce reverse stable isotope labelling (RIL) for assessing microbial activity in BAC filters. We incubated BAC samples from three different BAC filters (two granular activated carbon- and one extruded activated carbon-based) in a buffer amended with 13C-labelled bicarbonate. By monitoring the release of 12C–CO2 from the mineralization of DOC, we could demonstrate the successful application of RIL in analysing microbial DOC degradation during drinking water treatment. Changing the water flow rates through BAC filters did not alter the microbial activities, even though apparent DOC removal efficiencies changed accordingly. Microbial DOC degradation activities quickly recovered from backwashing which was applied for removing particulate impurities and preventing clogging. The size distributions of activated carbon particles led to vertical stratification of microbial activities along the filter beds. Our results demonstrate that reverse isotope labelling is well suited to measure microbial DOC degradation on activated carbon particles, which provides a basis for improving operation and design of BAC filters.
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Zhu Y, Wang Y, Yan Y, Xue H. Rapid and Sensitive Quantification of Anammox Bacteria by Flow Cytometric Analysis Based on Catalyzed Reporter Deposition Fluorescence In Situ Hybridization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:6895-6905. [PMID: 31120737 DOI: 10.1021/acs.est.9b01017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The quantification of anammox bacteria is crucial to manipulation and management of anammox biosystems. In this study, we proposed a protocol specifically optimized for quantification of anammox bacteria abundance in anammox sludge samples using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) and flow cytometry (FCM) in combination (Flow-CARD-FISH). We optimized the pretreatment procedures for FCM-compatibility, as well as the permeabilization, hybridization and staining protocols of the CARD-FISH. The developed method was compared with other methods for specific bacteria quantification (standard FISH, 16S rRNA sequencing and quantitative polymerase chain reaction). Anammox sludge samples could be disaggregated effectively by sonication (specific energy of 90 kJ·L-1 with MLVSS of 3-5 g·L-1) with the mixed ionic and nonionic dispersants Triton X-100 (5%) and sodium pyrophosphate (10 mM). Lysozyme treatment for permeabilizing bacterial cell walls and H2O2 incubation for completely quenching endogenous peroxidase of anammox sludges were essential to fluorescence enhancement and false positive signals control, respectively. Horseradish peroxidase molecules labeling at 20 °C for 12 h and the fluorescent tyramide labeling at 25 °C for 30 min with a fluorescent substrate concentration of 1:50 maintained the balance between increasing the signal and preventing nonspecific binding. Flow-CARD-FISH results showed that anammox bacteria absolute abundance in two different sludge samples were (2.31 ± 0.01) × 107 and (1.20 ± 0.06) × 107 cells·mL-1, respectively, with the relative abundances of 36.7 ± 4.1% and 26.5 ± 3.7%, respectively, comparable with those of qPCR and 16S rRNA sequencing analysis. The enhanced fluorescence signals induced by CARD-FISH combined with the high quantitative fluorescence sensitivity of FCM provide a rapid and sensitive method that yields accurate quantification results that will be valuable in future studies of microbial community determination.
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Affiliation(s)
- Yijing Zhu
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering , Tongji University , Siping Road , Shanghai 200092 , P. R. China
| | - Yayi Wang
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering , Tongji University , Siping Road , Shanghai 200092 , P. R. China
| | - Yuan Yan
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering , Tongji University , Siping Road , Shanghai 200092 , P. R. China
| | - Hao Xue
- State Key Laboratory of Pollution Control and Resources Reuse, Shanghai Institute of Pollution Control and Ecological Security, College of Environmental Science and Engineering , Tongji University , Siping Road , Shanghai 200092 , P. R. China
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Kirisits MJ, Emelko MB, Pinto AJ. Applying biotechnology for drinking water biofiltration: advancing science and practice. Curr Opin Biotechnol 2019; 57:197-204. [DOI: 10.1016/j.copbio.2019.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 04/12/2019] [Accepted: 05/09/2019] [Indexed: 12/17/2022]
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28
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Brown M, Hands C, Coello-Garcia T, Sani B, Ott A, Smith S, Davenport R. A flow cytometry method for bacterial quantification and biomass estimates in activated sludge. J Microbiol Methods 2019; 160:73-83. [DOI: 10.1016/j.mimet.2019.03.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/15/2019] [Accepted: 03/25/2019] [Indexed: 10/27/2022]
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29
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Crognale S, Casentini B, Amalfitano S, Fazi S, Petruccioli M, Rossetti S. Biological As(III) oxidation in biofilters by using native groundwater microorganisms. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 651:93-102. [PMID: 30227294 DOI: 10.1016/j.scitotenv.2018.09.176] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 09/13/2018] [Accepted: 09/13/2018] [Indexed: 06/08/2023]
Abstract
Arsenic (As) contamination in drinking water represents a worldwide threat to human health. During last decades, the exploitation of microbial As-transformations has been proposed for bioremediation applications. Among biological methods for As-contaminated water treatment, microbial As(III)-oxidation is one of the most promising approaches since it can be coupled to commonly used adsorption removal technologies, without requiring the addition of chemicals and producing toxic by-products. Despite the As(III) oxidation capability has been described in several bacterial pure or enrichment cultures, very little is known about the real potentialities of this process when mixed microbial communities, naturally occurring in As contaminated waters, are used. This study highlighted the contribution of native groundwater bacteria to As(III)-oxidation in biofilters, under conditions suitable for a household-scale treatment system. This work elucidated the influence of a variety of experimental conditions (i.e., various filling materials, flow rates, As(III) inflow concentration, As(III):As(V) ratio, filter volumes) on the microbially-mediated As(III)-oxidation process in terms of oxidation efficiency and rate. The highest oxidation efficiencies (up to 90% in 3 h) were found on coarse sand biofilters treating total initial As concentration of 100 μg L-1. The detailed microbial characterization of the As(III) oxidizing biofilms revealed the occurrence of several OTUs affiliated with families known to oxidize As(III) (e.g., Burkholderiaceae, Comamonadaceae, Rhodobacteraceae, Xanthomonadaceae). Furthermore, As-related functional genes increased in biofilter systems in line with the observed oxidative performances.
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Affiliation(s)
- Simona Crognale
- Water Research Institute, National Research Council of Italy (IRSA - CNR), Via Salaria, km 29.300, Monterotondo, Rome 00015, Italy
| | - Barbara Casentini
- Water Research Institute, National Research Council of Italy (IRSA - CNR), Via Salaria, km 29.300, Monterotondo, Rome 00015, Italy
| | - Stefano Amalfitano
- Water Research Institute, National Research Council of Italy (IRSA - CNR), Via Salaria, km 29.300, Monterotondo, Rome 00015, Italy
| | - Stefano Fazi
- Water Research Institute, National Research Council of Italy (IRSA - CNR), Via Salaria, km 29.300, Monterotondo, Rome 00015, Italy
| | - Maurizio Petruccioli
- Department for Innovation in Agroforestry and Biological systems (DIBAF), University of Tuscia, Viterbo, Italy
| | - Simona Rossetti
- Water Research Institute, National Research Council of Italy (IRSA - CNR), Via Salaria, km 29.300, Monterotondo, Rome 00015, Italy.
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