4 Material und Umwelt
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Organisationseinheit der BAM
- 4 Material und Umwelt (139) (entfernen)
Since nowadays people spend most of their time indoors, a healthy environment is essential. Volatile organic compounds (VOCs) emitted from furniture and building materials are reported to cause health complaints. Therefore, the usage of low emitting materials will improve the indoor air quality. Quantitative VOC emission testing is usually conducted in emission test chambers under specified controlled conditions as described in DIN 16000-9 and DIN EN 16516.
For reasons of quality control/quality assurance (QC/QA) and for a better comparability of test results from different laboratories, suitable emission reference materials (ERM) are needed. Here, it is important to have a homogenous material with known emission rates over a specific time. Different approaches can be found in literature, inter alia polymer films loaded with the target compound to be released again, or a lacquer material to which a VOC mixture is added. After curing of the lacquer, the material can be loaded into a test chamber. Drawback of those approaches are their relatively fast decreasing emission profiles. For QC/QA purposes according to the test standards, VOC sources with constant emission profiles are desirable.
The EU-funded research project MetrIAQ “Metrology for the determination of emissions of dangerous substances from building materials into indoor air” is working on a multi-component ERM with an envisaged instability of ≤ 10 % in the emission rate over at least 14 days.
Within a doctoral thesis porous materials are impregnated with VOCs. Supercritical CO2 is used as solvent. Thus, the impregnated material does not contain any solvent that may show a measurable amount of emission in the emission test chamber. Furthermore, CO2 has the benefits to have a good availability and low costs. For the selection of porous materials several properties like the pore size, the surface, and the interaction with the components in the atmosphere need to be considered. The impregnation method is optimised while the different porous materials are tested. For the selection of porous materials the pores need to be large enough for the VOC molecules, further influence of the pore size is tested.
We demonstrate a 2D platform based on high contrast wetting patterns suitable for miniaturized microbiological assays.
In principal, superhydrophilic spots are surrounded by a superhydrophobic surface area. The special structure of the superhydrophilic functional surface ensures that liquids, e.g. bacterial suspensions or biocide solutions, spread immediately and evenly on this surface without passing the wetting boundary. This feature allows a homogenous distribution of bacteria or chemical substances on well defined lateral dimensions. The superhydrophilic spots may also serve as substrate for bacterial biofilms. Due to the high wetting contrast and the fabrication process, it is possible to minimize the test areas as well as their distance to each other.
We demonstrate the fabrication process of the high wetting contrast platform and also present a microbiological assay as an application example. Advantages of this platform are the use of low volumes and its potential of automated analysis.
Development of a methodical approach for in-situ analysis of modern reverse paintings on glass
(2018)
The technique of painting on the reverse side of glass was rediscovered by artists in the early 20th century and gained great popularity, especially in Germany. In contrast to other paint techniques (e.g. panel and mural painting), the paint layers are applied in reverse succession starting with the foremost paint layer and ending with the primer (backmost layer). The paintings are viewed in reflected light, thus revealing an impressive gloss, luminosity and depth of colour.
Scientific investigation of the material provides important information for appropriate conservation concepts. Transport of the precious and fragile objects to the lab is often not feasible. Therefore, in-situ, non-invasive analysis is necessary to analyse colorants and binders. However, some analytical problems need to be considered: due to the reverse paint stratigraphy in reverse paintings on glass, the measured layer is always the backmost one. The analytical possibilities are extremely reduced, when the back is covered by a metal foil (or by paper, carton etc.). However, measurements through the glass (using Raman and VIS) can still yield information on the colourants of the front layer.
When the paint layer is accessible, we start our procedure using X-ray fluorescence (Tracer III-SD, Bruker AXS Microanalysis GmbH, 40 kV, 15 μA) and VIS reflectance spectroscopy (SPM 100, Gretag-Imaging AG). Both techniques provide first information on the inorganic colourants. Raman measurements (i-Raman®Plus, Bwtek inc., 785 nm, 50× objective, resolution 4 cm-1) are then carried out to clarify uncertain XRF measurements and to identify synthetic organic pigments (SOP). Diffuse Reflection-Infrared-Fourier-Transform Spectroscopy (DRIFTS; ExoScan, Agilent GmbH, 4000–650 cm-1, 500 scans, spectral resolution 4 cm-1) is used for the classification of the binders. Moreover, it may help to identify SOP, when fluorescence dominates the Raman signal. This analytical sequence yields the best results, when time is the limiting factor.
We present two in-situ studies of the paintings “Kreuzabnahme” (1914-15) by Carlo Mense and “Stadt am Morgen” (1921) by Walter Dexel. The painting “Kreuzabnahme” is an outstanding piece in Mense’s ɶuvre, because the glass plate was painted on both sides (Fig. 1). The results of the back-side show mainly inorganic pigments: basic lead white, talc, red and brown ochre, cinnabar, chrome yellow, viridian, ultramarine blue, Prussian blue and bone black. The classification of binding media using DRIFTS yields positive results for drying oil. Acrylic resin could be identified in two areas, resulting from a previous restauration treatment. For the front side painting, Mense used basic lead white, cinnabar, chrome yellow and umbra as pigments and oil as binder.
Measurements of the abstract painting “Stadt am Morgen” by Walter Dexel show zinc white, basic lead white, chalk, cinnabar, red lead, strontium yellow, cadmium yellow, cobalt blue, Prussian blue, ultramarine blue, brown ochre and bone black as pigments. Moreover, synthetic alizarin (PR83) was identified as dark red colorant. The results of DRIFTS classify oil as binding media.
We conclude that, the use of complementary spectroscopic methods yields the best results for in-situ analysis of reverse paintings on glass.
The technique of painting on the reverse side of glass was rediscovered by artists in the early 20th century. The artist group “Der Blaue Reiter” around Wassily Kandinsky and Franz Marc got in touch with this technique in 1908 and 1909. In the following years it gained great popularity, especially in Germany. Nevertheless, the technique has not received its due appreciation in art history. It was considered as stained glass. However, the paint layers are applied cold, hence this artistic technique doesn’t involve a firing step.
Our multidisciplinary project investigates the art historic backgrounds, the painting techniques and materials of modern reverse paintings on glass. More than 1000 paintings from ~100 artists were discovered in the framework of our project. A selection of 60 paintings could be analyzed using non-invasive, in-situ methods such as Raman and VIS spectroscopy, Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) and X-ray fluorescence (XRF). In this paper we want to point out the key role of Raman spectroscopy for our research. It offers the unique opportunity to measure paint layers from both sides. (front = through the glass; reverse = directly on the paint layer).
This work addresses the identification of synthetic organic pigments (SOP) in ten modern reverse paintings on glass (1912-1946) by means of an in-situ multi-analytical approach. The combination of the complimentary properties of mobile Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) enabled the detection of sixteen SOP even in complex mixtures with inorganic compounds and binders. For the β-naphthol pigments, both Raman and DRIFTS yield appropriate results. DRIFTS was the preferred method for the detection of synthetic alizarin (PR83). Its diagnostic band pattern even allows its detection in complex mixtures with mineral pigments, binders and fillers. Raman spectroscopy yielded distinctive spectra for the triaryl carbonium pigments (PG1, PV2, PR81) and the two-yellow azo SOP (PY3, PY12), whereas DRIFT spectra were affected by extensive band overlapping. This may also occur in Raman spectra, but in less problematic amounts. Fluorescence is the major problem with Raman and it significantly hampers the SOP spectra even with the 785 nm laser. On the one hand the big spot size of DRIFTS (10 mm) limits the technique to rather large sampling areas, whereas the use of a 50× objective for in-situ Raman measurements permits a focus on small spots and aggregated SOP flakes. Moreover, “environmental” factors like temperature changes, artificial light, limited space and vibrations when people pass by need to be considered for in-situ measurements in museums.
Finally, the results show the experimental use of SOP in modern reverse glass paintings. Among several rare SOP (e.g. PB52, PR81), two of them (PG1, PV2) have never been reported before in any artwork.
First insights into Chinese reverse glass paintings gained by non invasive spectroscopic analysis
(2019)
A non-invasive methodological approach (X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), Raman spectroscopy) has been carried out to identify the pigments and classify the binding media in two Chinese reverse glass paintings (The Archer, Yingying and Hongniang) from the late 19th and early 20th centuries. The results reveal a combined use of traditional Chinese and imported European materials. Several pigments like cinnabar, lead white, orpiment, carbon black and copper-arsenic green (probably emerald green) were found in both paintings; red lead, artificial ultramarine blue, Prussian blue and ochre appear in at least one of the paintings.
The presence of portlandite (Ca(OH)2) along calcite (CaCO3) in the fine-grained, white backing layer of Yingying and Hongniang indicates the presence of limewash. In Chinese tradition, limewash was produced from clamshells, and was then sold as clamshell white. In contrast to the Japanese pigment, Chinese clamshell white was made of finely grounded shells, which were heated over a low fire. The residue (CaO) forms portlandite (Ca(OH)2) when water is continuously added. This water-rich mixture is applied on the painting. Portlandite reacts with atmospheric CO2 during drying and forms fine-grained calcite (CaCO3) [1,2].
The identification of emerald green (The Archer) suggests an earliest manufacturing date in the 1830s [3] and promotes the sinological dating of the painting. Drying oil was classified as a binding media in most areas of both paintings. However, the orange background of The Archer yielded prominent bands of both proteinaceous and fatty binder.
Background. Disinfection is an important mitigation strategy to control and prevent the spread of infections. Incomplete or incorrect usage of disinfection may promote evolution of resistance against disinfectants and antibiotics. Ideally, disinfection reduces the number of surviving bacteria and the chance for resistance evolution. Resistance describes the ability to grow in previously inhibitory concentrations of an antimicrobial, whereas tolerance is associated with enhanced survival of lethal doses. Individual bacteria from the same population can display considerable heterogeneity in their ability to survive treatment (i.e. tolerance) with antimicrobials, which can result in unexpected treatment failure.
Objective. In this study, we investigated six active substances of disinfectants, preservatives, and antiseptics against a population of E. coli to identify the presence of a tolerant subpopulation.
Methods. We performed time-kill experiments and analyzed the data with a mathematical model to statistically infer whether the data is best explained by the presence of a tolerant subpopulation.
Results. The analysis identified bimodal kill kinetics for benzalkonium chloride, didecyldimethylammonium chloride, and isopropanol. In contrast, kill kinetics by chlorhexidine, glutaraldehyde, and hydrogen peroxide were best explained by unimodal kill kinetics. These findings have implications for the risk of disinfection failure. In addition, we are currently performing adaptive laboratory evolution (ALE) experiments with the different disinfectants to investigate the potential consequences of tolerant sub-populations for the evolution of antimicrobial resistance and tolerance.
Background. Disinfection is an important mitigation strategy to control and prevent the spread of infections. Incomplete or incorrect usage of disinfection may promote evolution of resistance against disinfectants and antibiotics. Ideally, disinfection reduces the number of surviving bacteria and the chance for resistance evolution. Resistance describes the ability to grow in previously inhibitory concentrations of an antimicrobial, whereas tolerance is associated with enhanced survival of lethal doses. Individual bacteria from the same population can display considerable heterogeneity in their ability to survive treatment (i.e. tolerance) with antimicrobials, which can result in unexpected treatment failure.
Objective. In this study, we investigated six active substances of disinfectants, preservatives, and antiseptics against a population of E. coli to identify the presence of a tolerant subpopulation.
Methods. We performed time-kill experiments and analyzed the data with a mathematical model to statistically infer whether the data is best explained by the presence of a tolerant subpopulation.
Results. The analysis identified bimodal kill kinetics for benzalkonium chloride, didecyldimethylammonium chloride, and isopropanol. In contrast, kill kinetics by chlorhexidine, glutaraldehyde, and hydrogen peroxide were best explained by unimodal kill kinetics. These findings have implications for the risk of disinfection failure. In addition, we are currently performing adaptive laboratory evolution (ALE) experiments with the different disinfectants to investigate the potential consequences of tolerant sub-populations for the evolution of antimicrobial resistance and tolerance.
In the transition to the Circular Economy (CE) model, where the added value of products is kept as long as possible and waste is eliminated, the sustainable management of raw materials plays a key role. In above CE model, especial attention is paid to CRMs which are economically and strategically important for the European economy, but have a high-risk associated with their supply.
One of the most important element which can not be replaced and is an essential element for human nutrition, yet limited resource is phosphorus (P). An importance of issues related to sustainable P management results from EU legislation, which indicated P as a Critical Raw Material (CRM).
The sustainable management of P-resources is especially important for the Baltic region. A consequence of waterborne loads passing into the sea, mainly as wastewater with a high P content is the eutrophication of the Baltic Sea environment. Due to the largest inputs of P (37%) into the Baltic Sea originate from Poland, the development of sustainable solutions aimed at more rational P management for this country is externally important.
Due to the vital importance of phosphorus (P) and its increasing scarcity as a natural resource, phosphorus recovery has recently gained significant scientific and technical interest. An interesting sources of phosphorus are sewage sludge (SS) and sewage sludge ash (SSA) due to the major part of the phosphate from P rich wastewater is transferred to the sludge (approx. 90%). Despite the fact that the raw materials base is large (PURE report indicates that in 2020 the amount of sewage sludge generated in Poland will reach 180% of the dry matter of sewage sludge produced in 2010), at present recycling of phosphorus is not a commonly used practice in Poland.
Whereas the behavior of geosynthetics in landfill engineering is well studied and documented since decades, little is known on application in applications such as coastal protection or ballast layers for wind energy plants.
However, due to the rapid expansion of offshore wind energy, rising water levels and more extreme weather conditions as a result of climate change more and more hydraulic engineering projects will be realized in the future.
Construction with geosynthetics has various advantages, but it has to be ensured that there is no negative environmental impact from the application of geosynthetics in hydraulic engineering.
It is expected that any effect will be visible only on the long-term. Therefore, accelerated testing is needed to derive requirements for geosynthetics in hydraulic engineering.
Aschen und Schlacken aus der thermischen Abfallbehandlung enthalten eine Vielzahl von Schwermetallverbindungen. Für Antimon, Chrom, Kupfer, Molybdän und Vanadium werden in der neuen Ersatzbaustoffverordnung Eluatgrenzwerte für die Verwertung festgelegt. Aschen und Schlacken werden aus der Abfallverbrennungsanlage nass ausgetragen und vor einer Verwertung in der Regel mehrere Wochen gelagert. Dabei finden hydraulische Reaktionen statt und enthaltenes CaO wird zu einem Großteil in Calciumcarbonat umgewandelt. Während wässrige Eluate von frischen Aschen pH-Werte von 12 und höher aufweisen, sind die Eluate nach einigen Wochen weniger stark alkalisch. Die gemessenen Schwermetallkonzentrationen sind daher dann auch deutlich niedriger, mit Ausnahme von Antimon (Sb) und Vanadium (V). Hier steigen die Konzentration mit der Lagerungsdauer. Grund sind sinkende Konzentrationen von Ca-Ionen, die sonst zu einer Ausfällung von Antimonaten und Vanadaten führen. Zu hohe Eluatwerte von Sb und V können durch Sorption an Eisenoxidverbindungen gemindert werden. Als besonders wirkungsvoll hat sich Schwertmannit (Eisen-Oxyhydroxysulfat) erwiesen. Es entsteht durch Oxidation von pyrithaltigem Material durch Mikroorganismen und wird deshalb in Gebieten gefunden, in denen Braunkohle abgebaut wurde, z.B. in der Lausitz. Weitere untersuchte Eisenoxidverbindungen waren Hämatit und Schlämme aus der Abtrennung von Eisen und Mangan in Wasserwerken.
A mobile Bruker S2 Picofox TXRF spectrometer has been used in two field campaigns within the EMPIR env07 AEROMET project for the on-site analysis of cascade impactor aerosol samples.The results show that even at moderate air pollution levels – i.e.PM10 fairly below 20 μg/m³ - element mass concentrations in air in the range of 100 pg/m³could be measured in up to 13 size bins after sampling times of less than only 0.5 days.
The OECD test guidelines (TGs) for testing chemicals have been widely used for regulatory purposes all over the world since the establishment of the Mutual Acceptance of Data (MAD) principle in 1984. This MAD principle ensures that, if a chemical is tested under the Good Laboratory Practice (GLP) conditions accordingly to an OECD TG, the data should be accepted in all OECD countries. The TGs have been developed, harmonized, internationally validated (round robin tests) and adopted by OECD countries to be used for the physical-chemical characterisation, fate estimation, and hazard identification for risk assessment of various chemicals. In addition to the TGs, OECD Guidance Documents (GDs) usually provide guidance on how to use TGs and how to interpret the results. These GDs do not have to be fully experimentally validated, and hence they are not under MAD, but they are based on relevant published scientific research.
But are the existing TGs and the related GDs applicable and adequate for the regulatory testing of nanomaterials? In general, it is accepted that most of the "endpoints" or more precisely measurement variables are applicable also for nanomaterials. However, for some endpoints new or amended TGs are needed. In addition, several GDs are needed to give more precise advice on the test performance in order to gain regulatory relevant data on nanomaterials.
The poster will present the status quo on recent TGs and GDs development for nanomaterials at OECD level with relevance for physical-chemical characterisation. Emphasis will be given to the proposed OECD TG on particle size and size distribution for manufactured nanomaterials. The development of such a TG is of special importance as particle size and size distribution is considered as major information for nanomaterial identification and characterization. A reliable and reproducible characterisation of particle size and size distribution is also needed for chemicals risk assessment of nanomaterials, for instance to interpret and compare test results and - in future – to forecast interaction and effects of nanomaterials. The presented poster will illustrate the way from the idea for a new TG and new GD to an accepted OECD TG/GD.
Biofilm formation on materials leads to high costs in industrial processes, as well as in medical applications. This fact has stimulated interest in the development of new materials with improved surfaces to reduce bacterial adhesion.
We present a flow chamber system to test and quantify bacterial adhesion on materials that are part of antifouling concepts. The adhesion process is standardized and can be adapted to different bacteria in subaquatic of subaerial environments. It is combined with a standardized evaluation procedure based on statistical evidence.
DHN (1,8-dihydroxynaphthalene) melanin is produced by different Ascomycetes via slightly differing biosynthetic routes. The polyketide synthases (PKS) release the heptaketide YWA1, the hexaketide AT4HN or the pentaketide T4HN. The first two products are deacetylated by ‘yellowish-green’ hydrolases to T4HN, and T4HN is further converted by a core set of enzymes to DHN. Final polymerization steps are accomplished by multicopper oxidases (MCOs). The involved genes are tightly clustered, partially clustered or widely distributed in the genomes of DHN melanin-producing fungi. DHN melanogenesis is often regulated in a spatial and temporal fashion resulting e.g. in melanized reproduction, survival and/or infection structures. In contrast, a polyphyletic group of Ascomycetes (microcolonial fungi/ black yeast) dwelling in hostile habitats such as bare rock surfaces in hot and cold deserts, exhibits constitutive melanogenesis. Here, we report on the identification and functional characterization of the DHN melanogenic genes of Knufia petricola as a representative of the Chaetothyriales, the sister order of the Eurotiales. Orthologs for all melanogenic genes were identified in the genome of K. petricola A95, including one gene encoding the polyketide synthase (KpPKS1), two genes encoding ‘yellowish-green’ hydrolases (KpYGH1,2), two genes encoding THN reductases (KpTHR1,2) and one gene encoding a scytalone dehydratase (KpSDH1). Ten genes encoding MCOs were identified, all MCOs are predicted to be secreted. The genes are not clustered in the genome but are highly expressed. Gene functions are studied by generation of single, double, and multiple deletion mutants in K. petricola and by heterologous expression in Saccharomyces cerevisiae for reconstruction of the synthesis pathway.
Black yeasts form a polyphyletic group of Ascomycota that colonize bare surfaces like rocks, facades of buildings, and solar panels. Their protective adaptations enable an adequate response to fluctuating and diverse temperature, water and UV radiation stresses. Together with bacteria and algae they form sub-aerial biofilms (SAB) this way discoloring and weathering the surfaces they grow on. Strain A95 of Knufia petricola (Eurotiomycetes, Chaetothyriales) displays both typical yeast-like cell growth and constitutive dihydroxynaphthalene (DHN) melanogenesis. Along with the cyanobacterium Nostoc punctiforme as photobiont, it is already used in a model system for studying SAB formation and bio-weathering. Applying the recently developed tools for the generation of deletion mutants will allow to define gene functions and to identify genes critical for abiotic and biotic interactions. We present a chromosome-level genome assembly and annotation for K. petricola A95. The genome was assembled with MaSuRCA using a hybrid assembly approach of Illumina MiSeq and PacBio SMRT sequencing data. The resulting assembly consists of 17 contigs including the complete mitochondrial genome and five complete chromosomes. It shows indication of repeat-induced point mutations (RIP). Supported by RNA sequencing data from eight different growth conditions, 10,994 genes were predicted with the BRAKER2 pipeline. Functional annotation of genes was obtained from general functional annotation databases and the fungal specific database FungiPath. Comparative analyses are in progress to identify genes specific to black yeasts, that may facilitate the survival on exposed surfaces. In sum, the genome sequence of K. petricola is a valuable resource to gain insight into the protein inventory and functional pathways of extremotolerant and symbiosis-capable fungi.
Dihydroxynaphthalene (DHN) melanin is produced by diverse Ascomycetes via slightly differing biosynthetic routes. The polyketide synthases (PKS) release the heptaketide YWA1, the hexaketide AT4HN or the pentaketide T4HN. The first two products are deacetylated by ‘yellowish-green’ hydrolases to T4HN, and T4HN is further converted by a core set of enzymes to DHN. Final polymerization steps are accomplished by multicopper oxidases. DHN melanogenesis is often regulated in a spatial and temporal fashion resulting e.g., in melanized reproduction and survival structures of the foliar plant pathogen Botrytis cinerea (Schumacher 2016, Mol Microbiol). In contrast, microcolonial black fungi exhibit constitutive melanogenesis. Here, DHN melanin builds a protective layer around all vegetative cells thus contributing to the survival of diverse environmental stresses even without specialized reproduction structures. For studying the regulation and relevance of DHN melanogenesis for tolerance of abiotic and biotic stresses, adhesion to substrates and subsequent damage of colonized surfaces, the rock-inhabiting fungus Knufia petricola was chosen as gene functions in this fungus can be studied by CRISPR/Cas9-based genome editing. The putative melanogenic genes were identified in the genome of K. petricola, deleted to confirm their involvement in DHN melanogenesis and co-expressed in Saccharomyces cerevisiae for reconstruction of the synthesis pathway. Phenotypes of deletion mutants are studied for specifying the functions of DHN melanin in K. petricola.
DHN (1,8-dihydroxynaphthalene) melanin is produced by Ascomycetes via slightly differing synthetic routes. Polyketide synthases release YWA1, AT4HN or T4HN. YWA1 and AT4HN are deacetylated by ‘yellowish-green’ hydrolases, and T4HN is converted by a core set of enzymes to DHN. Final polymerization steps are accomplished by multicopper oxidases. The melanogenic genes are tightly, partially or not clustered in the genomes, and are often regulated in a spatial and/or temporal fashion. By contrast, microcolonial fungi/black yeasts – a polyphyletic group of Ascomycetes dwelling in hostile habitats such as bare rock surfaces – feature constitutive DHN melanogenesis. Here, we report on the DHN melanogenic genes of Knufia petricola (Eurotiomycetes/Chaetothyriales).
Assessing co-selection of biocide and antibiotic resistance in wastewater microbial communities
(2022)
Biocides are used for a wide range of purposes, including disinfectants or preservatives. Biocides play a major role in the prevention of microbial infections in healthcare and animal husbandry. The use of biocides often leads to the discharge of active biocidal substances into wastewater streams, causing the exposure of wastewater microbial communities to subinhibitory concentrations. In turn, it is known that wastewater treatment plants (WWTP) are hotspots for antibiotic resistant bacteria. Since similar mechanisms confer resistance to biocides and antibiotics, exposure to biocides can result in co-selection of antibiotic resistant bacteria in WWTP due to biocides. Here, we investigate the magnitude and the drivers of co-selection of antibiotic resistance in natural wastewater microbial communities upon biocide exposure. Microbial communities will be sampled at the WWTP Ruhleben in Berlin and characterized regarding their biocide and antibiotic resistance. Changes in the resistance level after exposure to different biocides will be determined by enumerating resistant and non-resistant E. coli and heterotrophic bacteria on selective plates with and without several biocides and antibiotics. Moreover, we are establishing a synthetic community comprising about 100 environmental E. coli isolates each with different antimicrobial resistance traits. Each isolate will be tagged with a unique DNA-barcode. All isolates will be pooled and exposed to different biocides at various concentrations. The barcode labeling enables us to determine the abundance of each isolate at the beginning and end of the experiment by transposon-tag sequencing. The project results will inform risk assessment of the effects of biocidal residues on antimicrobial resistance selection in WWTP.
The project is part of the BIOCIDE consortium funded within the call on Aquatic pollutants by JPI-AMR, JPI-OCEANS and JPI-WATER.