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Berruti I, Nahim-Granados S, Abeledo-Lameiro MJ, Oller I, Polo-López MI. Recent advances in solar photochemical processes for water and wastewater disinfection. CHEMICAL ENGINEERING JOURNAL ADVANCES 2022. [DOI: 10.1016/j.ceja.2022.100248] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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2
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Herraiz-Carboné M, Cotillas S, Lacasa E, Vasileva M, Sainz de Baranda C, Riquelme E, Cañizares P, Sáez C. Disinfection of polymicrobial urines by electrochemical oxidation: Removal of antibiotic-resistant bacteria and genes. JOURNAL OF HAZARDOUS MATERIALS 2022; 426:128028. [PMID: 34923384 DOI: 10.1016/j.jhazmat.2021.128028] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 12/05/2021] [Accepted: 12/06/2021] [Indexed: 06/14/2023]
Abstract
In this work, data obtained from the University Hospital Complex of Albacete (Spain) were selected as a case study to carry out the disinfection experiments. To do this, different configurations of electrochemical reactors were tested for the disinfection of complex urines. Results showed that 4-6 logs bacterial removal were achieved for every bacterium tested when working with a microfluidic flow-through reactor after 180 min (0.423 Ah dm-3). The MIKROZON® cell reached a total disinfection after 60 min (1.212 Ah dm-3), causing severe damages induced in the cell walls observed in SEM images. The concentration profiles of the electrogenerated disinfectants in solution could explain the differences observed. Additionally, a mean decrease in the ARGs concentration ranked as follows: blaKPC (4.18-logs) > blaTEM (3.96-logs) > ermB (3.23-logs) using the MIKROZON® cell. This electro-ozonizer could be considered as a suitable alternative to reduce the risk of antibiotic resistance spread. Hence, this study provides an insight into different electrochemical reactors for the disinfection of complex hospital urine matrices and contributes to reduce the spread of antibiotic resistance through the elimination of ARGs. A topic of great importance nowadays that needs to be further studied.
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Affiliation(s)
- Miguel Herraiz-Carboné
- Department of Chemical Engineering, Higher Technical School of Industrial Engineering, University of Castilla-La Mancha, Edificio Infante Don Juan Manuel, Campus Universitario s/n, 02071 Albacete, Spain
| | - Salvador Cotillas
- Department of Chemical Engineering and Materials, Faculty of Chemical Sciences, Complutense University of Madrid, Avenida Complutense s/n, 28040 Madrid, Spain.
| | - Engracia Lacasa
- Department of Chemical Engineering, Higher Technical School of Industrial Engineering, University of Castilla-La Mancha, Edificio Infante Don Juan Manuel, Campus Universitario s/n, 02071 Albacete, Spain.
| | - Marina Vasileva
- Department of Chemical Engineering, Higher Technical School of Industrial Engineering, University of Castilla-La Mancha, Edificio Infante Don Juan Manuel, Campus Universitario s/n, 02071 Albacete, Spain
| | - Caridad Sainz de Baranda
- Clinical Parasitology and Microbiology Area, University Hospital Complex of Albacete, C/Hermanos Falcó 37, 02006 Albacete, Spain
| | - Eva Riquelme
- Clinical Parasitology and Microbiology Area, University Hospital Complex of Albacete, C/Hermanos Falcó 37, 02006 Albacete, Spain
| | - Pablo Cañizares
- Department of Chemical Engineering, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Edificio Enrique Costa Novella, Campus Universitario s/n, 13005 Ciudad Real, Spain
| | - Cristina Sáez
- Department of Chemical Engineering, Faculty of Chemical Sciences and Technologies, University of Castilla-La Mancha, Edificio Enrique Costa Novella, Campus Universitario s/n, 13005 Ciudad Real, Spain
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Wang M, Ateia M, Awfa D, Yoshimura C. Regrowth of bacteria after light-based disinfection - What we know and where we go from here. CHEMOSPHERE 2021; 268:128850. [PMID: 33187648 DOI: 10.1016/j.chemosphere.2020.128850] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/29/2020] [Accepted: 10/31/2020] [Indexed: 06/11/2023]
Abstract
Regrowth of bacteria after water/wastewater disinfection is a serious risk to public health, particularly when such pathogens carry antibiotic resistance genes. Despite increasing interest in light-based disinfection using ultraviolet or solar radiation, the mechanism of bacterial regrowth and their concentration upon light exposure (i.e., during storage, or after discharge into rivers or lakes) remain poorly understood. Therefore, we present a focused critical review to 1) elucidate regrowth mechanisms, 2) summarize the pros and cons of available experimental designs and detection techniques for regrowth evaluation, and 3) provide an outlook of key research directions for further investigations of post-disinfection bacterial regrowth. Bacterial regrowth can occur through reactivation from a viable but non-culturable state, repair of photo-induced DNA damage, and reproduction of bacteria surviving disinfection. Many studies have underestimated the degree of actual regrowth because of the use of simple experimental designs and plate count methods, which cannot quantify actual abundance of viable bacteria. Further research should investigate the effects of various factors on bacterial regrowth in realistic conditions in regrowth tests and adopt multiplex detection methods that combine culture-based and culture-independent approaches. An accurate understanding of the mechanisms involved in bacterial regrowth following disinfection is critical for safeguarding public health and aquatic environments.
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Affiliation(s)
- Manna Wang
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan
| | - Mohamed Ateia
- Department of Chemistry, Northwestern University, Evanston, IL, 60208, USA.
| | - Dion Awfa
- Water and Wastewater Engineering Research Group, Faculty of Civil and Environmental Engineering, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung, 40132, Indonesia
| | - Chihiro Yoshimura
- Department of Civil and Environmental Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8552, Japan
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Waso M, Khan S, Singh A, McMichael S, Ahmed W, Fernández-Ibáñez P, Byrne JA, Khan W. Predatory bacteria in combination with solar disinfection and solar photocatalysis for the treatment of rainwater. WATER RESEARCH 2020; 169:115281. [PMID: 31733621 DOI: 10.1016/j.watres.2019.115281] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/01/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
The predatory bacterium, Bdellovibrio bacteriovorus, was applied as a biological pre-treatment to solar disinfection and solar photocatalytic disinfection for rainwater treatment. The photocatalyst used was immobilised titanium-dioxide reduced graphene oxide. The pre-treatment followed by solar photocatalysis for 120 min under natural sunlight reduced the viable counts of Klebsiella pneumoniae from 2.00 × 109 colony forming units (CFU)/mL to below the detection limit (BDL) (<1 CFU/100 μL). Correspondingly, ethidium monoazide bromide quantitative PCR analysis indicated a high total log reduction in K. pneumoniae gene copies (GC)/mL (5.85 logs after solar photocatalysis for 240 min). In contrast, solar disinfection and solar photocatalysis without the biological pre-treatment were more effective for Enterococcus faecium disinfection as the viable counts of E. faecium were reduced by 8.00 logs (from 1.00 × 108 CFU/mL to BDL) and the gene copies were reduced by ∼3.39 logs (from 2.09 × 106 GC/mL to ∼9.00 × 102 GC/mL) after 240 min of treatment. Predatory bacteria can be applied as a pre-treatment to solar disinfection and solar photocatalytic treatment to enhance the removal efficiency of Gram-negative bacteria, which is crucial for the development of a targeted water treatment approach.
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Affiliation(s)
- M Waso
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - S Khan
- Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Doornfontein, 2028, South Africa
| | - A Singh
- Nanotechnology and Integrated BioEngineering Centre, Ulster University, Jordanstown Campus, Shore Road, Newtownabbey, Belfast, BT37 0QB, United Kingdom
| | - S McMichael
- Nanotechnology and Integrated BioEngineering Centre, Ulster University, Jordanstown Campus, Shore Road, Newtownabbey, Belfast, BT37 0QB, United Kingdom
| | - W Ahmed
- CSIRO Land and Water, Ecosciences Precinct, 41 Boggo Road, Queensland, 4102, Australia
| | - P Fernández-Ibáñez
- Nanotechnology and Integrated BioEngineering Centre, Ulster University, Jordanstown Campus, Shore Road, Newtownabbey, Belfast, BT37 0QB, United Kingdom
| | - J A Byrne
- Nanotechnology and Integrated BioEngineering Centre, Ulster University, Jordanstown Campus, Shore Road, Newtownabbey, Belfast, BT37 0QB, United Kingdom
| | - W Khan
- Department of Microbiology, Faculty of Science, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
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Ponce-Robles L, Oller I, Polo-López MI, Rivas-Ibáñez G, Malato S. Microbiological evaluation of combined advanced chemical-biological oxidation technologies for the treatment of cork boiling wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 687:567-576. [PMID: 31216510 DOI: 10.1016/j.scitotenv.2019.05.335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 05/22/2019] [Accepted: 05/22/2019] [Indexed: 06/09/2023]
Abstract
This paper contains a multidisciplinary approach that will contribute to design and properly evaluate a treatment line for complex biorecalcitrant wastewaters. To demonstrate this approach a specific industrial wastewater (cork boiling wastewater, CBW) was used. A treatment line based on a coagulation-flocculation step followed by an Advanced Oxidation Process (AOP) (solar photo-Fenton) and combined with an aerobic biological system was evaluated. Applied microbiological techniques: optical microscopy, plate count, DNA extraction and qPCR, indicated that some communities disappeared after the activated sludge adaptation period to the partially treated wastewater, while communities that did not disappear were damaged: 2-log reduction of total heterotrophic bacteria (THB) and a decrease in DNA concentration from 200 ng/μL to 65 ng/μL were observed. Therefore, chemical and microbiological results obtained along the set of experiments, suggested the inefficiency of the combined treatment option between solar photo-Fenton and advanced aerobic biological systems for CBW. This led to the necessity of applying solar photo-Fenton without combining with biotreatment and with the objective of improving the effluent quality enough for being reused in the own industry. Toxicity tests, based on different organisms (after coagulation-flocculation followed by solar photo-Fenton), showed increase on acute toxicity (from 46% to 71% by respirometric assays) and the development of chronic toxicity (from 21-29% to 83-90% also measured by respirometric assays), made evident the incompatibility of this type of wastewater with a biological treatment even after the application of an AOP.
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Affiliation(s)
- L Ponce-Robles
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain
| | - I Oller
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain.
| | - M I Polo-López
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain
| | - G Rivas-Ibáñez
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain
| | - S Malato
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain
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Ponce-Robles L, Polo-López MI, Oller I, Garrido-Cardenas JA, Malato S. Practical approach to the evaluation of industrial wastewater treatment by the application of advanced microbiological techniques. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 166:123-131. [PMID: 30265875 DOI: 10.1016/j.ecoenv.2018.09.044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 09/07/2018] [Accepted: 09/08/2018] [Indexed: 06/08/2023]
Abstract
In cork industry, the operation of boiling raw cork generates large volumes of wastewater named Cork Boiling Wastewater (CBW). The main characteristics are the low biodegradability and medium to low acute toxicity, resulting in the necessity of designing advanced biological treatments by possible conventional activated sludge adaptation. In order to evaluate the variation of bacterial population along that process, a study based on optical microscopy, plate count, DNA extraction, qPCR and massive sequencing techniques was performed. Results showed a diminution of the total and volatile solids (TSS and VSS), jointly with a decrease in DNA concentration, general bacteria (16 S) and ammonia-oxidizing bacteria (AOB). After a few hours of testing, diverse microbiological species died while others showed a possible adaptation of the biological system, accompained by a dissolved organic carbon (DOC) reduction. In addition, toxicity tests based on activated sludge showed the development of chronic toxicity through the contact time. Combination of classical and advanced microbiological techniques, such as quantitative real time Polymerase Chain Reaction (qPCR) and metagenomics, was essential to predict the variation of species during the experiment and to conclude if effective biological adaptation could be finally attained for the target complex wastewater.
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Affiliation(s)
- L Ponce-Robles
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain
| | - M I Polo-López
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain
| | - I Oller
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain.
| | | | - S Malato
- Plataforma Solar de Almería-CIEMAT, Carretera de Senés Km 4, 04200 Tabernas, Almería, Spain; CIESOL, Joint Centre of the University of Almería-CIEMAT, 04120 Almería, Spain
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Uyguner Demirel CS, Birben NC, Bekbolet M. A comprehensive review on the use of second generation TiO 2 photocatalysts: Microorganism inactivation. CHEMOSPHERE 2018; 211:420-448. [PMID: 30077938 DOI: 10.1016/j.chemosphere.2018.07.121] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 07/04/2018] [Accepted: 07/21/2018] [Indexed: 05/12/2023]
Abstract
Photocatalytic disinfection practices have been applied for decades and attract current interest along with the developments in synthesis of novel photocatalysts. A survey based investigation was performed for elucidation of photocatalytic treatment details as well as disinfection mechanism of microorganisms. The present work brings significant information on the utilization of second generation TiO2 photocatalysts for inactivation of microorganisms typically using E. coli as the model microorganism. Special interest was devoted to the role of organic matrix either generated during treatment or as a natural component. Studies on photocatalytic disinfection were extensively reviewed and evaluated with respect to basic operational parameters related to photocatalysis, and types and properties of microorganisms investigated. Degradation mechanism and behavior of microorganisms towards reactive oxygen species during disinfection and organic matrix effects were also addressed. For successful utilization and effective assessment of visible light active photocatalysts, standard protocols for disinfection activity testing have to be set. Further improvement of the efficiency of these materials would be promising for future applications in water treatment processes.
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Affiliation(s)
| | - Nazmiye Cemre Birben
- Bogazici University, Institute of Environmental Sciences, 34342, Bebek, Istanbul, Turkey.
| | - Miray Bekbolet
- Bogazici University, Institute of Environmental Sciences, 34342, Bebek, Istanbul, Turkey.
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Moreira NFF, Narciso-da-Rocha C, Polo-López MI, Pastrana-Martínez LM, Faria JL, Manaia CM, Fernández-Ibáñez P, Nunes OC, Silva AMT. Solar treatment (H 2O 2, TiO 2-P25 and GO-TiO 2 photocatalysis, photo-Fenton) of organic micropollutants, human pathogen indicators, antibiotic resistant bacteria and related genes in urban wastewater. WATER RESEARCH 2018; 135:195-206. [PMID: 29475109 DOI: 10.1016/j.watres.2018.01.064] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 12/23/2017] [Accepted: 01/26/2018] [Indexed: 05/29/2023]
Abstract
Solar-driven advanced oxidation processes were studied in a pilot-scale photoreactor, as tertiary treatments of effluents from an urban wastewater treatment plant. Solar-H2O2, heterogeneous photocatalysis (with and/or without the addition of H2O2 and employing three different photocatalysts) and the photo-Fenton process were investigated. Chemical (sulfamethoxazole, carbamazepine, and diclofenac) and biological contaminants (faecal contamination indicators, their antibiotic resistant counterparts, 16S rRNA and antibiotic resistance genes), as well as the whole bacterial community, were characterized. Heterogeneous photocatalysis using TiO2-P25 and assisted with H2O2 (P25/H2O2) was the most efficient process on the degradation of the chemical organic micropollutants, attaining levels below the limits of quantification in less than 4 h of treatment (corresponding to QUV < 40 kJ L-1). This performance was followed by the same process without H2O2, using TiO2-P25 or a composite material based on graphene oxide and TiO2. Regarding the biological indicators, total faecal coliforms and enterococci and their antibiotic resistant (tetracycline and ciprofloxacin) counterparts were reduced to values close, or beneath, the detection limit (1 CFU 100 mL-1) for all treatments employing H2O2, even upon storage of the treated wastewater for 3-days. Moreover, P25/H2O2 and solar-H2O2 were the most efficient processes in the reduction of the abundance (gene copy number per volume of wastewater) of the analysed genes. However, this reduction was transient for 16S rRNA, intI1 and sul1 genes, since after 3-days storage of the treated wastewater their abundance increased to values close to pre-treatment levels. Similar behaviour was observed for the genes qnrS (using TiO2-P25), blaCTX-M and blaTEM (using TiO2-P25 and TiO2-P25/H2O2). Interestingly, higher proportions of sequence reads affiliated to the phylum Proteobacteria (Beta- and Gammaproteobacteria) were found after 3-days storage of treated wastewater than before its treatment. Members of the genera Pseudomonas, Rheinheimera and Methylotenera were among those with overgrowth.
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Affiliation(s)
- Nuno F F Moreira
- Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Carlos Narciso-da-Rocha
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal
| | | | - Luisa M Pastrana-Martínez
- Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Joaquim L Faria
- Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Célia M Manaia
- Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal
| | - Pilar Fernández-Ibáñez
- Plataforma Solar de Almeria - CIEMAT, P.O. Box 22, 04200, Tabernas, Almeria, Spain; Nanotechnology and Integrated BioEngineering Centre, School of Engineering, University of Ulster, Newtownabbey, Northern Ireland BT37 0QB, United Kingdom.
| | - Olga C Nunes
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal
| | - Adrián M T Silva
- Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
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Aguas Y, Hincapie M, Fernández-Ibáñez P, Polo-López MI. Solar photocatalytic disinfection of agricultural pathogenic fungi (Curvularia sp.) in real urban wastewater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 607-608:1213-1224. [PMID: 28732400 DOI: 10.1016/j.scitotenv.2017.07.085] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/10/2017] [Accepted: 07/10/2017] [Indexed: 06/07/2023]
Abstract
The interest in developing alternative water disinfection methods that increase the access to irrigation water free of pathogens for agricultural purposes is increasing in the last decades. Advanced Oxidation Processes (AOPs) have been demonstrated to be very efficient for the abatement of several kind of pathogens in contaminated water. The purpose of the current study was to evaluate and compare the capability of several solar AOPs for the inactivation of resistant spores of agricultural fungi. Solar photoassisted H2O2, solar photo-Fenton at acid and near-neutral pH, and solar heterogeneous photocatalysis using TiO2, with and without H2O2, have been studied for the inactivation of spores of Curvularia sp., a phytopathogenic fungi worldwide found in soils and crops. Different concentrations of reagents and catalysts were evaluated at bench scale (solar vessel reactors, 200mL) and at pilot plant scale (solar Compound Parabolic Collector-CPC reactor, 20L) under natural solar radiation using distilled water (DW) and real secondary effluents (SE) from a municipal wastewater treatment plant. Inactivation order of Curvularia sp. in distilled water was determined, i.e. TiO2/H2O2/sunlight (100/50mgL-1)>H2O2/sunlight (40mgL-1)>TiO2/sunlight (100mgL-1)>photo-Fenton with 5/10mgL-1 of Fe2+/H2O2 at pH3 and near-neutral pH. For the case of SE, at near neutral pH, the most efficient solar process was H2O2/Solar (60mgL-1); nevertheless, the best Curvularia sp. inactivation rate was obtained with photo-Fenton (10/20mgL-1 of Fe2+/H2O2) requiring a previous water adicification to pH3, within 300 and 210min of solar treatment, respectively. These results show the efficiency of solar AOPs as a feasible option for the inactivation of resistant pathogens in water for crops irrigation, even in the presence of organic matter (average Dissolved Organic Carbon (DOC): 24mgL-1), and open a window for future wastewater reclamation and irrigation use.
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Affiliation(s)
- Yelitza Aguas
- Universidad de Sucre, School of Engineering, Cra 28 No 5-268, Sincelejo, Colombia; Universidad de Medellin, School of Engineering, Cra 87 No 30-65, Medellín, Colombia.
| | - Margarita Hincapie
- Universidad de Medellin, School of Engineering, Cra 87 No 30-65, Medellín, Colombia.
| | - Pilar Fernández-Ibáñez
- Nanotechnology and Integrated BioEngineering Centre, School of Engineering, University of Ulster, Newtownabbey, Northern Ireland BT37 0QB, United Kingdom.
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Comparison of EMA-, PMA- and DNase qPCR for the determination of microbial cell viability. Appl Microbiol Biotechnol 2017; 101:7371-7383. [PMID: 28875372 DOI: 10.1007/s00253-017-8471-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 07/21/2017] [Accepted: 08/03/2017] [Indexed: 01/13/2023]
Abstract
Ethidium monoazide (EMA) quantitative polymerase chain reaction (qPCR), propidium monoazide (PMA)-qPCR and DNase treatment in combination with qPCR were compared for the determination of microbial cell viability. Additionally, varying EMA and PMA concentrations were analysed to determine which dye and concentration allowed for the optimal identification of viable cells. Viable, heat treated (70 °C for 15 min) and autoclaved cultures of Legionella pneumophila, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus and Enterococcus faecalis were utilised in the respective viability assays. Analysis of the viable and heat-treated samples indicated that variable log reductions were recorded for both EMA [log reductions ranging from 0.01 to 2.71 (viable) and 0.27 to 2.85 (heat treated)], PMA [log reductions ranging from 0.06 to 1.02 (viable) and 0.62 to 2.46 (heat treated)] and DNase treatment [log reductions ranging from 0.06 to 0.82 (viable) and 0.70 to 2.91 (heat treated)], in comparison to the no viability treatment controls. Based on the results obtained, 6 μM EMA and 50 μM PMA were identified as the optimal dye concentrations as low log reductions were recorded (viable and heat-treated samples) in comparison to the no viability treatment control. In addition, the results recorded for the 6 μM EMA concentration were comparable to the results obtained for both the 50 μM PMA and the DNase treatment. The use of EMA-qPCR (6 μM) may therefore allow for the rapid identification and quantification of multiple intact opportunistic pathogens in water sources, which would benefit routine water quality monitoring following disinfection treatment.
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