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Each year, an immense amount of plastic debris enters marine ecosystems, much of which ends up in the Great Pacific Garbage Patch (GPGP). The plastic fragments are home to a diverse community of microorganisms, and while researchers have gained a better understanding of these marine plastic biofilms, we lack insights into the physiology and genomic potential of the bacteria that colonize them. Examining the lifestyle of plastic colonizers from the GPGP is particularly intriguing, as the high concentration of plastics in this accumulation zone might allow for a microbial adaptation to this unique man-made habitat. A range of pigmentation was observed in 67 isolated strains obtained directly from plastic pieces sampled from the GPGP surface water. Sequence comparison between the cultivated bacterial strains and the 16S rRNA gene amplicon dataset confirmed that most of the cultivates could also be captured through DNA-only methods. Whole genome analysis of four taxonomically diverse representatives revealed multiple carotenoid pathways, including those to produce less common glycosylated carotenoids, like sarcinaxanthin glucoside. Further, we identified a potentially new Rhodobacteraceae species containing a photosynthetic gene cluster (PGC). Absorption analysis confirmed the actual production of the carotenoids and bacteriochlorophyll a. Floating plastics represent a habitat with strong UV-light exposure, making the protection with antioxidant carotenoids as well as the ability to use light as an energy source highly beneficial traits for plastic colonizers. Our findings indicate, that the production of pigments is a common adaption mechanism for plastic-associated bacteria, and that plastic biofilms present a so far overlooked source of rare carotenoids and light-harvesting mechanisms.
Glutaraldehyde (GTA) is commonly used to disinfect medical equipment, in animal husbandry and in hydraulic fracturing. Its wide use bears the risk that microorganisms in different environments are exposed to potentially non-lethal doses of glutaraldehyde. To date, little is known about the effects of glutaraldehyde on the susceptibility of bacteria to antibiotics and its role in the selection of tolerant phenotypes.
Objectives
• To determine the effect of glutaraldehyde exposure on the survival of E. coli, S. aureus and P. aeruginosa to antibiotics
• To find the mechanistic basis for antibiotic tolerance upon glutaraldehyde exposure
Materials & Methods
Four bacterial isolates were exposed to sub-inhibitory glutaraldehyde. Antibiotic tolerance was determined by time-kill assays. Regrowth dynamics (lag times) were determined with ScanLag. E. coli was further investigated, using RNAseq to identify genes and processes involved in antibiotic tolerance. Mutants of candidate genes were screened for their antibiotic tolerance and heterogeneous target gene expression under stressed and unstressed conditions.
Results
Short-term exposure to sub-inhibitory levels of glutaraldehyde induced tolerance to high doses of bactericidal antibiotics. Tolerance to antibiotics was associated with highly heterogeneous regrowth dynamics and global transcriptome remodeling. Differentially expressed genes represented diverse biological functions and cellular components, including antibiotic efflux, metabolic processes, and the cell envelope. The heterogeneous regrowth dynamics and the diversity of the differentially expressed genes are likely related to the unspecific mode-of-action of glutaraldehyde. Among the many differentially expressed genes, several genes were identified that were not previously associated with antibiotic tolerance or persistence, which, when overexpressed alone, increased antibiotic tolerance.
Conclusion
Our results highlight how the big advantage of a disinfectant, its unspecific mode-of-action, can induce transient tolerance to antibiotics in bacteria. These findings have implications for 1.) settings where disinfectants and antibiotics are used in proximity, such as hospitals and animal husbandry, and 2.) for the selection dynamics of tolerant bacteria in fluctuating environments because of the trade-off that arises from overcoming the lag phase as fast as possible and maintaining antibiotic tolerance.
In-vivo mutagenesis of the rock inhabitant Knufia petricola by a customized Ac/Ds transposon system
(2023)
Microcolonial black fungi ubiquitously inhabit sun-exposed natural and man-made surfaces of our planet. To promote genetic studies, CRISPR/Cas9-based genome editing was implemented in the rock-inhabiting fungus Knufia petricola (Eurotiomycetes/ Chaetothyriales). Now efficient targeted mutagenesis of K. petricola - as a representative of the polyphyletic group of black fungi - enables the elucidation of extremotolerance, oligotrophism, unusual types of cell division, mineral weathering and symbiotic interactions. Even more progress on assigning functions to yet unknown genes can be achieved by a forward genetics approach. We chose the two-component Activator/Dissociation (Ac/Ds) transposon system from maize for generating K. petricola insertional mutants by in-vivo mutagenesis. For the optimal use of this genetic tool, an inducible promoter i.e, from the metabolism-independent Tet-on system, was combined with the AcTPase-coding sequence enabling the regulatable transposition of the resistance cassette-containing Ds transposon. In total, six auxotrophic Ac/Ds starter strains containing the Ds transposon at different position of ade2, ura3 or ppt1 were generated. The cultivation of these strains with doxycycline for induction of TET::Ac and subsequent selection of cells on ADE/URA/LYS-lacking media resulted in prototrophic colonies (revertants) for most Ac/Ds strains. Amplicon sequencing of excision sites revealed characteristic footprint patterns, proving that the transposon jumped. For identifying unknown Ds re-insertions sites, the thermal asymmetric interlaced (TAIL)-PCR was successfully implemented. First identified Ds re-insertion sites suggest that the distribution pattern may depend on the excision site. Currently, transposition frequencies and genome-wide distribution of re-insertion sites are studied in different Ac/Ds starter strains to identify the best candidate for generating saturated mutant libraries. This transposon mutagenesis strategy is also interesting for studying other black fungi, because once the Ac and Ds components are integrated in the genome, the fungus ‘only’ needs to be cultivated for generating insertional mutants.
The exponential rise in the number of fungal genomes sequenced by next-generation sequencing techniques makes it necessary to increase efforts to correctly annotate and assign gene functions. There are two possibilities to explore a genome and its gene functions. The hypothesis-based method proves the function of already existing gene/allele candidates by targeted mutagenesis - so called reverse genetics. The basis of forward genetics approaches is the random mutagenesis of the genome, followed by screening of obtained mutants for the phenotype of interest, and identification of the mutated genes in the respective mutants. This strategy is hypothesis-generating, means it is necessary to verify the relationship between the detected mutations and the observed phenotype by targeted mutagenesis of the identified gene. We developed a toolbox for editing the genome of the rock inhabitant Knufia petricola [Eurotiomycetes, Chaetothyriales] that allows the study of the phenotypic characteristics of black fungi such as the regulation of pigment synthesis, general stress responses, oligotrophy, and the unusual modes of cell division by advanced reverse and forward genetics approaches. The toolbox includes the annotated genome sequence of strain A95, efficient strategies for CRISPR/Cas9-based genome editing and live-cell imaging using genetically encoded fluorescent proteins, as well as protocols for -omics approaches and for simulation of mineral weathering. A forward genetics approach using transposon mutagenesis is currently developed for identifying essential genes. The established protocols and knowledge gained from K. petricola form a starting point for making other fungi from extreme environments accessible to genetic manipulation.
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, a polyphyletic group of Ascomycetes (microcolonial fungi/ black yeasts) dwelling in hostile habitats such as bare rock surfaces in hot and cold deserts, exhibits 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 relevance of constitutive 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 DHN-deficient mutants are studied. Here, we will discuss the role of the DHN melanin layer on the outer cell wall in tolerating UV irradiation.
Sustainable product policy is one pillar of the European Green Deal and the Circular Economy Action Plan. The European Commission is to begin to address recycling, recycled content and repair under the Ecodesign Directive and very likely in the announced European Sustainable Products Regulation. In addition, initiatives on recyclability and other aspects of sustainable products can be observed in France under the Ecomodulation Approach for some electrical and electronic products. Neither the Commission's ambitions nor the Ecomodulation Approach have so far led to a crucially better ecodesign of products.
Therefore, at the EU level, indices for reparability (already developed for smartphones and tablets), recyclability and recycled content of products are being discussed within the Ecodesign legislative framework in an attempt to achieve better ecodesign through advanced consumer purchasing decisions. The product standards requested by the European Commission to assess the recyclability (EN4555) and recycled content (EN4557) of energy-related products have already been published, but are purely based on a mass-based approach. Material-specific aspects such as the environmental impact or the financial, technical and redesign efforts required by manufacturers to facilitate the recycling and use of recycled materials are not addressed. Materials that are easy to recycle and use and have a high recycled content, such as copper, are treated in the same way as plastics that are difficult to recycle and use in products as post-consumer recycled plastics. Including such aspects would be essential to trigger environmentally relevant and significant improvements in product design.
Der Vortrag fasst die Schnittmenge zwischen Normung und Politik bezüglich einer zirkulären Wirtschaft (Circular Economy) zusammen. Es wird an konkreten Schlüsselgremien und praktischen Beispielen gezeigt, wie Circular Economy bereits heute durch Normung gelingen kann und welche Zuarbeit durch die Politik von den Normungsgremien erbeten wird.
Understanding the fundamentals of bioreceptivity enables the developement of functionalized materials. Concrete as the most used building material worldwide is of special interest as microbially greened panels may represent an alternative to classic façade greening with plants.
As standards are not ye established, material characterization in context as well as bioreceptivity assessment itself has been proven to be difficult. The presentation reviews first results of methods adapted for this application.
This presentation summarizes outcomes of the CUSP projects POLYRISK and PlasticsFatE according to thermoanalytical methods.It highlights the importants of analytical methods to measure physical and chemical properties of the test materials. These informations are neccessary for interpretation of the toxicological test results.
Design and construction of a rainfall simulator to test metal runoff at atmospheric conditions
(2023)
A rainfall simulator was presented as an environmental assessment tool to quantify wash-off concentrations from metallic materials. It is part of the RUNOFF-project, which studies and re-assesses the durability of roofing and facade materials under current atmospheric conditions in Germany.
Studying building materials is important as they have a significant impact on achieving a variety of goals and targets within the sustainable developments goals (SDGs). The durability of materials is essential to reach sustainability. However, the durability of metallic materials is strongly depended on climate conditions, which have changed as a result of technical measures in industry, climate change and increasing urbanisation. In Germany at least, the data base is not up-to-date leading to prediction models regarding corrosion resistance and durability of metallic materials which can no longer be trusted and therefore need to be re-assessed and updated. Also, not only the demand for sustainable but also environmentally friendly building materials has increased dramatically. A number of construction materials produce chemical hazards, and therefore have negative impacts on water quality, soils health and ecosystems. To limit these impacts, environmental assessment methods and tools are needed to measure and quantify the inputs and outputs of building materials throughout their lifetime.
The presentation gives general information about the European Standard EN 16516 “Construction products – Assessment of release of dangerous substances – Determination of emissions into indoor air”. This test standard was developed based on the mandate M/366 of the European commission and is a horizontal reference method for the determination of volatile organic compounds (VOC) from different classes of construction (building) products. Specific test conditions are to be selected by the product TCs (technical committees) in a way that a product is tested under its intended condition of use.
The test is based on the use of emission test chambers which are operated at constant air change rate and climate (23°C, 50 % r.h.) over 28 days. The standard defines the conditions and requirements for the measurement including loading factor, air change rate, sampling, analysis and calculation of emission rates of the substances. A 30 m³ reference room is described which is used to calculate air concentrations from the determined emission rates.
The standard EN 16516 enables the evaluation of construction products regarding their emissions into indoor air under defined and comparable conditions. The evaluation includes the determination of identified target compounds, non-identified target compounds, volatile carcinogenic compounds and the sum values TVOC, TSVOC and R.
Glutaraldehyde is widely used as a disinfectant and preservative, but little is known about its effects on bacterial susceptibility to antibiotics and the selection of tolerant phenotypes. We found that short-term exposure to sub-inhibitory levels of glutaraldehyde makes E. coli resistant to high doses of bactericidal antibiotics from different classes. This tolerance is associated with delayed, heterogeneous regrowth dynamics and global transcriptome remodeling. We identified over 1200 differentially expressed genes, including those related to antibiotic efflux, metabolic processes, and the cell envelope. The cells entered a disrupted state likely due to the unspecific mode-of-action of glutaraldehyde. Despite this unregulated response, we identified several differentially expressed genes not previously associated with antibiotic tolerance or persistence that induce antibiotic tolerance when overexpressed alone. These findings highlight how the unspecific mode-of-action of disinfectants can make bacteria temporarily resistant to antibiotics. They have implications for settings where disinfectants and antibiotics are used in close proximity, such as hospitals and animal husbandry, and for the selection dynamics of tolerant pheno- and genotypes in fluctuating environments where microorganisms are exposed to these substances, such as sewage systems. A trade-off arises from overcoming the disrupted state as quickly as possible and maintaining antibiotic tolerance.
Glutaraldehyde is widely used as a disinfectant and preservative, but little is known about its effects on bacterial susceptibility to antibiotics and the selection of tolerant phenotypes. We found that short-term exposure to sub-inhibitory levels of glutaraldehyde makes E. coli resistant to high doses of bactericidal antibiotics from different classes. This tolerance is associated with delayed, heterogeneous regrowth dynamics and global transcriptome remodeling. We identified over 1200 differentially expressed genes, including those related to antibiotic efflux, metabolic processes, and the cell envelope. The cells entered a disrupted state likely due to the unspecific mode-of-action of glutaraldehyde. Despite this unregulated response, we identified several differentially expressed genes not previously associated with antibiotic tolerance or persistence that induce antibiotic tolerance when overexpressed alone. These findings highlight how the unspecific mode-of-action of disinfectants can make bacteria temporarily resistant to antibiotics. They have implications for settings where disinfectants and antibiotics are used in close proximity, such as hospitals and animal husbandry, and for the selection dynamics of tolerant pheno- and genotypes in fluctuating environments where microorganisms are exposed to these substances, such as sewage systems. A trade-off arises from overcoming the disrupted state as quickly as possible and maintaining antibiotic tolerance.
By tracing sustainability impacts along the supply chain, certification schemes and labels are crucial to unlock the potential of bio-based systems in achieving several SDGs. However, the rapid proliferation of certification schemes and labels led to questioning their effectiveness and robustness and to what extent they deliver important outcomes, in line with sustainability policy priorities. The STAR4BBS project develops indicators and a monitoring system for assessing the effectiveness and robustness of existing certification schemes and labels, applicable to biological feedstock and bio-based materials and products.
Der Vortrag stellt das Forschungsvorhaben RUNOFF vor, welcher auf der zweitägigen Veranstaltung „24. Projekttage der Bauforschung“ gehalten wurde. Die Präsentation erläutert zunächst die Bedeutung der Abschwemmung von Metallionen für die Bauindustrie und Umwelt. Dabei werden Faktoren, welche den Schadstofftransport im urbanen Raum begünstigen sowie Stadtentwässerungstypen vorgestellt. Anschließend folgen Folien zum wissenschaftlichen Hintergrund zur Ausbildung von Deckschichten, aktuellen Wissensstand sowie Lücken in der Korrosionsforschung von metallenen Werkstoffen unter atmosphärischen Bedingungen. Nach einer kurzen Übersicht zu den Hauptzielen des Forschungsvorhabens wurde detaillierter auf die Versuchsdurchführung sowie fünf der acht Arbeitspakete mitsamt Zwischenergebnissen eingegangen.
In Deutschland fallen aktuell pro Jahr über 5 Mio. Tonnen Hausmüllverbrennungs-aschen (HMVA) an. Eine Verwertung dieser Aschen und Schlacken ist in Deutschland möglich und findet überwiegend im Deponiebau statt. Für die Verwertung sind in der Ersatzbaustoffverordnung Eluatgrenzwerte für Schwermetalle und einige andere Parameter vorgesehen.
Der Umgang mit HMVA könnte durch eine Einstufung als gefährlicher Abfall erschwert werden. Maßgeblich für die Einstufung eines Abfalls als gefährlich oder ungefährlich sind die gefahrenrelevanten Eigenschaften HP 1 bis HP 15 nach Anhang III der Richtlinie 2008/98/EG über Abfälle mit dort festgelegten Konzentrationsgrenzen. Für HMVA ist im Wesentlichen nur der Parameter HP 14 (Ökotoxizität) von Bedeutung. Dafür sind entscheidend die Gehalte an chemischen Verbindungen mit den Gefahrenhinweiscodes (hazard statement code, HSC) H400, H410, H411, H412 und H413. Eine detaillierte Diskussion zu den übrigen Gefahreneigenschaften bei HMVA findet sich in der Literatur. Die Einstufung als gefährlicher Abfall erfolgt nach festgelegten Rechenregeln.
Die BAM bearbeitet ein durch das UBA gefördertes Forschungsprojekt zur Erfassung und Bewertung von Analysedaten zu Aschen und Schlacken aus Abfallverbrennungsanlagen. Die Ergebnisse des Vorhabens sollen bei der Weiterentwicklung des vorhandenen Konzeptes für eine bundeseinheitlichen Untersuchung und abfallrechtlichen Einordnung von Aschen und Schlacken aus deutschen Abfallverbrennungsanlagen unterstützend herangezogen werden. Im Vortrag werden Verfahren zur quantitativen Bestimmung der einstufungsrelevanten Verbindungen vorgestellt: 1.) der Praxisleitfaden von ITAD und IGAM, 2.) Methode basierend auf der Bioverfügbarkeit und 3.) Methode basierend auf Speziierungsanalyse.
Im Rahmen des Vortrages wurde ein kurzer kurzer Einstieg in die Circular Economy und die Schnittmenge zur Politik, speziell der nationalen und europäischen Rechtssetzung gegeben. Weiter wurde an praktischen Beispielen gezeigt, wie Circular Economy bereits heute durch Normung gelingen kann und wo es Verbesserungsbedarf gibt. Außerdem wurde ein Überblick über bestehende und zukünftige Legislativvorgaben gegeben.
Significant Cu-deposition and precipitation only occurred in combination with carbon steel. High-alloyed materials prevent the disturbing Cu-agglomeration. Pb-deposition and precipitation only occurred in combination with carbon steel. No negative Pb-effect could be observed in combination with high-alloyed steels. High alloyed corrosion resistant alloys are suitable and shall be chosen for future design of the piping system, either in massive or in cladded form, to prevent unwanted interactions with brine components.
Der Vortrag umfasst eine Einsortierung der Circular Economy in der Normung, skizziert die Inhalte der DIN/DKE/VDI-Normungsroadmap Circular Economy bezüglich Digitalisierung, Elektrotechnik und IKT sowie Batterien und zeigt Schnittstellen zur Politik. Zum Schluss zeigt der Vortrag erste Ansätze zur Umsetzung der in der Normungsroadmap beschriebenen Normungsbedarfe.
Kunststoffdichtungsbahnen (KDB) aus PE-HD (Polyethylen hoher Dichte) werden häufig zur Abdichtung von Bauwerken in der Geotechnik verwendet. Diese Produkte werden aus einem Kunststoff mit relativ komplexer Zusammensetzung hergestellt. Um eine Aussage über die Haltbarkeit von KDB aus PE-HD treffen zu können, muss das Materialverhalten berücksichtigt werden. In diesem Zusammenhang sind die wichtigsten Aspekte der Dauerhaftigkeit die Spannungsrissbeständigkeit und die Beständigkeit gegen Oxidation. Verschiedene PE-Sorten weisen eine unterschiedliche Spannungsrissbeständigkeit auf. Um dieser Eigenschaft von PE-HD zu begegnen, werden nur KDB aus sehr hochwertigen Rohstoffen zugelassen. Auf der anderen Seite werden hohe Anforderungen an die umgebenden Schichten, wie Auflager und Schutzschicht gestellt, um möglichst geringe Spannungen zu erzeugen und damit Dehnungen die Dehnungen der KDB gering zu halten. Bestimmte Medien, die bei den betreffenden Prüfungen verwendet werden, dürfen nicht mehr in der EU in Verkehr gebracht werden. Im Folgenden sollen die Zusammenhänge in Kürze dargestellt werden. Darüber hinaus sollen Diskussionen und Änderungen der Zulassungsrichtlinie für Schutzschichten im und durch den Fachbeirat vorgestellt werden.
The roles of DHN melanin and the stress-activated MAP kinase in the rock inhabitant Knufia petricola
(2023)
Black fungi/yeasts exhibit high stress tolerance, yeast‑like or meristematic growth, and constitutive 1,8-dihydroxynaphthalene (DHN) melanin formation. Due to their slow growth, robust cell walls and the lack of sexual cycles and genetic tools, the underlying mechanisms of their phenotypic traits have remained largely unexplored. Using recently developed genetic tools, it is now possible to manipulate the genome of the rock-inhabiting model fungus Knufia petricola. Thus, gene functions and the cell biology of black fungi can be studied using CRISPR/Cas9-based genome editing and live-cell imaging with genetically encoded fluorescent proteins. Here, we are addressing the question to which extent constitutive pigment formation (melanin and carotenoids) and responses mediated by the stress-activated mitogen-activated protein (MAP) kinase contribute to the observed extremotolerance of K. petricola. The mutations of pks1, phs1 and both genes result in melanin-free (pink), carotenoid-free (black) and pigment-free (white) strains, respectively. The other putative melanogenic genes were identified in the genome, deleted to confirm their involvement in DHN melanogenesis and co-expressed in Saccharomyces cerevisiae for reconstruction of the synthesis pathway. Sak1 encoding the stress-activated MAP kinase was deleted in the wild-type and different pigment-deficient backgrounds. Growth of the obtained single, double and triple deletion mutants was tested by droplet tests on media supplemented with different stress-inducing agents. The Δsak1 mutants show slightly reduced growth rates even without environmental pressure and are hypersensitive to different stresses: e.g. osmotic, oxidative, membrane, pH and heat stress. Melanin-free Δsak1 mutants are more sensitive than black Δsak1 mutants to some but not all stress conditions, suggesting that melanin and the SAK1 pathway have complementary roles in protecting K. petricola from stress.
SRB are environmentally and industrially important microorganisms. The disadvantage of their metabolic activity (e.g. sulfate reduction) results in the formation of toxic sulfide that leads to microbial influenced corrosion. SRB have been responsible for biocorrosion of ferrous metal. One of mitigation strategy is the use of biocides. However, it has been shown that various bacteria develop antimicrobial resistance due to excessive use of biocides. Thus, a deeper understanding of the evolution of biocide resistance of SRB is necessary. Three commonly used biocides, THPS, BAC, and GLUT were applied to investigate the susceptibility of Desulfovibrio alaskensis G20.The minimum inhibitory and bactericidal concentration and the killing kinetics of the three biocides was determined. These results will be used to conduct evolution experiments to determine the evolution of resistance towards biocides of SRBs. The outcome of this work can be helpful to improve the management of MIC treatments.
Eines haben die Krisen dieses Jahrzehnts gemeinsam: Sie motivieren zum Handeln. Bezüglich der Klimakrise wird eine grundlegende Änderung unseres Wirtschaftens als wesentlicher Lösungsweg gesehen. Die aktuell praktizierte lineare Wertschöpfung führte zu Ressourcenknappheit und -abhängigkeit und trug aktiv zur Verstärkung des Klimawandels bei. Wie wir in diesem Jahrzehnt unseren Absprung von gewohnten Produktions-, Konsum- und Verwertungsmustern gestalten, wird entscheidend für die nächsten Jahrzehnte sein. Die Frage, wie bis 2030 die Transformation hin zu einer zirkulären Wirtschaft gelingen kann, wurde u.a. von der Circular Economy Initiative Deutschland beantwortet. Sie nennt zehn Handlungsschwerpunkte, wobei „Standardisierung“ mit an wichtigster Stelle steht. Dieses beruht auf Gegenseitigkeit. Auf der diesjährigen G7 Standardisation High-level Conference wurde Circular Economy zu dem Themabereich mit dem größten Potential für Klimaschutzmaßnahmen gesehen.
In 2022 haben DIN, DKE und VDI mit über 500 Fachexperten aus Wirtschaft, Wissenschaft und Politik an einer Normungsroadmap Circular Economy gearbeitet. Die BAM war in fünf von sieben Schwerpunktthemen beteiligt. Ziel der Roadmap ist es, einen Handlungsrahmen für die Normung und Standardisierung zu schaffen, der die Transformation hin zu einer Circular Economy fördert. Normen und Standards bilden den untergesetzlichen und technischen Rahmen, auf denen eine zirkuläre Wirtschaft aufwachsen kann. Sie definieren Schnittstellen und stellen eine klare Kommunikation zwischen den verschiedenen Phasen des zirkulären Kreislaufes sicher – sie machen einen Kreislauf erst möglich.
In der Präsentation sind die Highlights der Normungsroadmap Circular Economy dargestellt. Die Roadmap liefert einen Überblick über die aktuelle Normungslandschaft sowie die An- und Herausforderungen zu Schwerpunktthemen wie Elektrotechnik, Kunststoffe, Verpackungen, Textilien, Bauwerke, etc. Mit >250 Normungs- und Standardisierungsbedarfen zeigt die Roadmap konkrete Handlungsfelder auf, ebenfalls mit Überschneidungen zum Geschäftsfeld der BAM.
Rock-inhabiting black fungi are adapted to survive extreme stresses such as radiation and lack of water and are thus able to colonise arid material surfaces like solar panels and marble monuments. Black fungi can typically grow as one of two cell types: depending on the environmental conditions, they are able to form yeast-like cells or hyphal filaments. Knufia petricola is one member of the rock-inhabiting black fungi which functions as a model reference species. As there is no mathematical model for biofilm formation of RIF, we are going to develop a model for K. petricola which describes fungal growth on the level of individual cells adn biofilm formation.
Rock-inhabiting fungi are known to colonise air-exposed substrates like minerals, photovoltaic panels building facades and monuments, withstanding the various stresses these extreme habitats are known for. Here we show how both colonisation and stress resistance are linked to the properties of the fungal cell surface. By deleting genes involved in the synthesis of melanin and carotenoid pigments of the model rock-inhabiting fungus Knufia petricola via CRISPR-Cas and comparing the behaviour of the gene-deletion mutants with the wild type (WT), we studied the role of these genes in mineral colonisation and stress sensitivity. The extracellular polymeric substances (EPS) of biofilms of the WT and mutants were extracted, quantified and chemically characterised. We observed that the absence of melanin affected the quantity and composition of the produced EPS: melanin-deficient mutants synthesised more EPS containing fewer pullulan-related glycosidic linkages. Moreover, in mineral dissolution experiments, these mutants showed a lower ability to colonise the mineral olivine. We hypothesise that not melanin, but the pullulan-related linkages enabled the melanin-producing strains to attach more strongly to the mineral. Moreover, ICP-OES analysis of the aqueous mineral-derived solutes showed that biofilms of the K. petricola mutants which could attach were able to dissolve the olivine faster than those that could not. The same mutants were also characterised by their sensitivity to desiccation stress: only the mutant deficient in both melanin and carotenoid synthesis was more sensitive to desiccation compared to the WT, indicating that a combination of both pigments is critical to withstand desiccation. Overall, these results show the critical role of the cell surface in the specific capacities of rock-inhabiting fungi.
Materials are key for our modern communities. In particular metals play important roles in all areas of our daily life - from building materials to high tech products.
Due to the increasing consumption of metals and corresponding waste production, an elevated release into the environment takes place. Furthermore, metals in direct contact with the environment undergo corrosion leading to a release into the (aquatic) environment. Thus, lifespan of products/buildings are substantially reduced – hence unnecessary economic costs arise. Thus, research in this regard is needed within the force field of metal/material - environment.
Evaluating the environmental impact of materials as well as developing “safe” materials, new analytical methods are highly needed. One promising powerful tool is single cell-ICP-ToF-MS for multi-elemental analysis on a single cell/organism level.
Within this presentation the concept, strength as well as challenge of single cell-ICP-MS are briefly introduced. Two application examples are presented: (i) assessing the environmental impact of metals and (ii) the impact of the environment on metal-based materials and the derivation of potential environmental-friendly material protection strategies. These applications highlight the strength of new analytical approaches to explore the durability and safety of newly developed materials. Thus, analytical chemistry is one corner stone to transformation of modern society into circular economy (CEco).
(i) Diatoms are located at the bottom of the food chain. Thus, toxicological relevant metals taken up by diatoms possibly accumulate within the food web causing harmful effects. Diatoms are common test system in ecotoxicology. To investigate potential metal uptake and effects, we developed an on-line single cell-ICP-ToF-MS approach for multi-elemental diatom analysis. Our approach is a new potential tool in ecotoxicological testing for metal-based materials.
(ii) Next to classical corrosion processes, microorganisms are responsible for so called microbially influenced corrosion (MIC). MIC is a highly unpredictable process relying on interaction pathways between cells and the metal surface. Sheding light on MIC processes and derivate potential protection strategies, we applied single cell-ICP-ToF-MS for MIC research on a single bacteria/archaea level. It turned out that microorganism are taking up particular metals from alloys - thus, single bacteria-ICP-ToF-MS will enable development of corrosion protection strategies.
•Overview of expertise of division Biophotonics
•Functional molecular and nanoscale luminescent reporters, probes, and
sensors including design principles available from division Biophotonics
•Examples for pH and O2 responsive molecular probes and particle sensors
•Surface group quantification Analytical methods and cleavable probes
•Concepts & standards for the validation and traceability of optical measurements
Biocides used as material preservatives are in contact with various environments during direct application or passive leaching from protected materials [1]. Antimicrobial resistance (AMR) is a global health problem and the environment is an important compartment for the evolution and transmission of AMR [2,3]. Soil is an environment with a large reservoir of natural microbial communities and antimicrobial resistance (AMR) genes. Those natural microbial communities are frequently exposed to biocides used as material preservatives. Previous studies have shown that antibiotics, metals and pesticides affect the underlying processes of resistance evolution and spread; namely de novo mutagenesis and horizontal gene transfer by conjugation and transformation in microbial communities. However, it is unknown if active substances used in material preservatives are involved in these processes. We show that biocides used as material preservatives affect rates of mutation and conjugation in microorganism in a species- and substance-dependent manner, while rates of transformation are not directly affected. Our data highlights the importance of assessing the contribution of material preservatives on AMR evolution and spread in the environment.
Biocides used as material preservatives are in contact with various environments during direct application or passive leaching from protected materials. Antimicrobial resistance (AMR) is a global health problem and the environment is an important compartment for the evolution and transmission of AMR. Soil is an environment with a large reservoir of natural microbial communities and antimicrobial resistance (AMR) genes. Those natural microbial communities are frequently exposed to biocides used as material preservatives. Previous studies have shown that antibiotics, metals and pesticides affect the underlying processes of resistance evolution and spread; namely de novo mutagenesis and horizontal gene transfer by conjugation and transformation in microbial communities. However, it is unknown if active substances used in material preservatives are involved in these processes. We show that biocides used as material preservatives affect rates of mutation and conjugation in microorganism in a species- and substance-dependent manner, while rates of transformation are not directly affected. Our data highlights the importance of assessing the contribution of material preservatives on AMR evolution and spread in the environment.
Der Vortrag fasst den aktuellen Stand der Forschung an der BAM zum Thema "Biorezeptive Betonfassaden" zusammen. Während im Projekt Funktionsbeton der Einfluss der Textur von ultrahochfestem Beton auf die Biorezeptivität im Vordergrund steht, wird im Projekt Algenbiofilmfassade untersucht, inwieweit ein Biofilm künstlich auf Betonsubstraten etabliert werden kann.
Microbiologically influenced corrosion (MIC) is a highly unpredictable process dictated by the environment, microorganisms, and the respective electron source. Interaction pathways between cells and the metal surface remain unclear. The development of this novel single cell-inductively coupled plasma-time of flight-mass spectrometry analytical method and a MIC-specific staining procedure facilitate the investigation of steel-MIC interactions. With this it is possible to analyze the multi-elemental fingerprint of individual cells. The detection method revealed elemental selectivity for the corrosive methanogenic archaeal strain Methanobacterium-affiliated IM1. The interface between material and environmental analysis thus receives special attention, e.g., when considering MIC on solid steel. Hence, the possible uptake of individual elements from different steel samples is investigated. Results showed the cells responded at a single-cell level to the different types of supplemented elements and displayed the abilities to interact with chromium, vanadium, titanium, cobalt, and molybdenum from solid metal surfaces. The information obtained will be used in the future to elucidate underlying mechanisms and develop possible material protection concepts, thus combining modern methods of analytical sciences with materials research.
It is of high priority to capture the extent of microplastics (MP) contamination for understanding its impact and consequences to our environment. However, due to a lack of standardized methods, MP analysis as well as its quality assurance, is still a challenge. The thermal extraction desorption-gas chromatography/-mass spectrometry (TED-GC/MS) as a novel innovative thermoanalytic method can detect MP particles in environmental samples based on their decomposition products. According to MP analysis, a distinctively larger polyethylene (PE) content in comparison to other synthetic polymers was detected in environmental samples. Various substances within the matrix which have a similar molecular structure to PE, like fats and oils, might interfere with its marker and lead to an overestimation. In this investigation an automated extraction method, the accelerated solvent extraction (ASE), is introduced as quality control tool before TED-GC/MS measurement. Thereby, not the extract like usually used, but the solid filtrate is analyzed. The aim is to clean the environmental samples from solvent removable compounds which could lead to false positive signals and thus receive a more accurate PE mass. Consequently, a sample mimicking environmental samples with a defined matrix and a known polymer mass was generated. The common polymers polyethylene, polypropylene, polystyrene and styrene-butadiene rubber, used as an indication for tire wear, were added to the matrix. Different parameters for ASE extraction were varied such as different solvents, filters and purge time. Finally, a PE recovery rate of 91 % after extraction could be reached.
Calcium sulfate minerals are abundant in natural and engineered environments and they exist in the form of three hydrates: gypsum (CaSO4·2H2O), bassanite (CaSO4·0.5H2O), and anhydrite (CaSO4). Due to their relevance in natural and industrial processes, the formation pathways of these calcium sulfate phases from aqueous solution have been the subject of intensive research1.
The state-of-the-art of the calcium sulfate formation mechanisms builds upon and goes beyond what we have come to appreciate in the astounding intricacy of other mineral formation processes from ions in aqueous solutions. The original, and rather naive, 'textbook' image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species2. These include solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc.. In this context, a number of studies have already revealed that nucleation in the CaSO4-H2O system is non-classical, where the formation of the different crystalline phases involves several steps including a common amorphous precursor1, 3, 4.
In this contribution we show that the formation of the amorphous phase involves the aggregation of small primary particles into larger disordered aggregates exhibiting a "brick-in-the-wall" structure5, 6. The actual crystallization occurs by the restructuring and coalescence of the particles ("bricks") into a given calcium sulfate phase depending on the physicochemical conditions of the solution. Importantly, the rearrangement process does not continue until a (nearly-)perfect homogeneous single crystal is obtained. Instead it comes to a stop, or at least significantly slows down. Such a process thus yields a final imperfect mesocrystal, composed of smaller domains rather than a continuous crystal structure, within which the domains are separated by an amorphous (i.e. less ordered) calcium sulfate phase.
Hence, the non-classical crystallization process of CaSO4 yields a final imperfect mesocrystal with an overall morphology resembling that of a single crystal, yet composed of smaller nano-domains. Importantly, these observations reveal that organic-free calcium sulfate mesocrystals grown by a particle mediated-pathway preserve in the final crystal structure a “memory” or “imprint” of their non-classical nucleation process, something that has been overlooked until now. Furthermore, the nano-scale misalignment of the structural sub-units within these crystals can propagate through the length-scales, and be expressed macroscopically as misaligned zones/domains in large single crystals. Indeed, by considering large anhydrite crystals from the famous Naica Mine (“Cueva de los cristales”) we observed a suite of correlated self-similar void defects spanning multiple length-scales7. These flaws, in the macroscopic crystal, stem from “seeds of imperfection” originating from a particle-mediated nucleation pathway. Hence, building a crystal could be viewed as Nature stacking blocks in a game of Tetris, whilst slowly forgetting the games core concept and failing to fill rows completely.
Antimicrobial resistance (AMR) is a global health problem with the environment being an important compartment for the evolution, selection and transmission of AMR. These processes are impacted by pollution with antibiotics. However, biocides used as disinfectants and material preservatives are major pollutants by far excceding the market for antibiotics in terms of mass. Our work shows that biocides have the potential to affect evolutionary processes towards AMR by increasing the rates of de-novo mutation and conjugation. These effects depend on the species and biocidal substance. Importantly, chlorhexidine and quaternary ammonium compounds (QACs) affect rates of mutation and conjugation at environmentally relevant concentrations in E. coli. Moreover, our results show a connection between the RpoS-mediated general stress and the RecA-linked SOS response with increased rates of mutation and conjugation, but not for all biocides. Furthermore, our work highlights the potential of biocides to contribute to selection and transmission of AMR. We show that the application of biocides, especially QAC disinfectants, leads to the rapid evolution of tolerance (i.e. increased survival) in adaptive laboratory evolution (ALE) experiments. The evolved tolerant strains have a selective advantage in the presence of environmentally-relevant concentrations of antibiotics, which could lead to the stabilization of biocide tolerance in environments where biocides and antibiotics co-occur (e.g. wastewater, animal stables). ALE experiments with biocide tolerant strains indicate a decreased evolvability of resistance to antibiotics. Taken together, our work shows the importance of assessing the contribution of biocides on evolution, selection and transmission of AMR in the environment.
Bisphenol A (BPA) is widely used in many Polymers. Many outdoor applications are made from BPA-based materials which are exposed to a variety of environmental impacts, like temperature, solar radiation, rain, and others. This could lead to damaging and aging of the material which might cause leaching or migration of pollutants into the environment. To understand the fate and behavior different transformation products of selected Bisphenols will be generated and analyzed.
Der Fachbeirat kommt bereits seit 13 Jahren in seiner jetzigen Form zusammen, um Zulassungsrichtlinien, weitere Dokumente und fachliche Fragestellungen zu beraten. Die Zeit bringt auch personelle Veränderungen mit sich, darüber wollen wir berichten. Derzeit wird die Zulassungsrichtlinie für Schutzschichten im Fachbeirat und in seiner Arbeitsgruppe Geotextilien und Kunststoff Dränelemente (AG Geotextilien) überarbeitet. Zudem wurde die Zulassungsrichtlinie für Kunststoffdichtungsbahnen auf den aktuellen Stand der Regelsetzung und Normung gebracht. Bestimmte Medien, die hier bei einigen Prüfungen verwendet werden, dürfen nicht mehr in der EU in Verkehr gebracht werden. Hier werden die Hintergründe und Zusammenhänge in Kürze aufgezeigt. Zuletzt wird die Diskussion in Bezug auf den Einsatz von Rezyklaten in den zugelassenen Produkten aufgeführt.
Fluorescent semiconductor nanocrystals, also known as quantum dots (QDs), enabled many advancements in biotechnology, photovoltaics, photocatalysis, quantum computing and display devices. The high versatility of this nanomaterial is based on their unique size-tunable photoluminescence properties, which can be adjusted from the visible to the near-infrared range. In contrast to other nanomaterials, QDs made the transition from a laboratory curiosity to the utilization in commercial products, like the QLED television screen or in smartphone displays. The best investigated QDs are composed of heavy metals like cadmium or lead, which is not the best choice in terms of toxicity and environmental pollution. A more promising material is Indium Phosphide (InP), which is also currently used by Samsung, Sony and co. in the QLED displays.
In this contribution, I would like to give you a sneak peek behind the curtains of nanomaterial synthesis and show how this material is produced, how to stabilize their structural properties, and assess their toxicity in environmentally relevant conditions. Furthermore, I would like to present a synthesis method to accomplish the last open challenge in display technology of a blue luminescent LED based on QDs by introducing a new element to the InP QDs.
Deutschland befindet sich inmitten eines umfassenden Transformationsprozesses hin zu einer klimaneutralen und nachhaltigen Wirtschaft und Gesellschaft. Sowohl das Erreichen der Klimaziele als auch die Anpassung an die Folgen des Klimawandels fordern ein rasches, bestimmtes und gleichzeitiges Handeln in vielen Sektoren und Lebensbereichen.
Normen und Standards können einen wichtigen Beitrag zum Erreichen dieser Ziele leisten. So haben Normungsorganisationen weltweit mit der ISO London Declarationeinen Pakt zur Unterstützung des Klimas geschlossen. Das bestehende Normenwerk muss auf Klimawandel-Tauglichkeit überprüft und eine Überarbeitung angestoßen werden.
Der Klimawandel als Querschnittsthema betrifft alle Wirtschaftszweige, und daher bieten DIN, DKE und VDI mit dieser durch Impulsvorträge eingeleiteten Diskussionsreihe eine Plattform zum Austausch über Normung als Werkzeug zum Thema Klima mit allen Akteuren.
The talk is about microplastics in soil. Some results were presented with mainly state of the art according to microplastics in standardization.
Der Vortrag wurde im Rahmen der konstituierenden Sitzung des Arbeitskreises "Atmosphärische Korrosion" der GfKORR - Gesellschaft für Korrosionsschutz e.V. gehalten. Er stellt die zur Diskussion stehenden Fragestellungen und Herausforderungen im Bereich der atmosphärischen Korrosion zusammen, denen sich der neue Arbeitskreis widmen wird.
Microcolonial black fungi are inhabitants of exposed natural and man-made surfaces in all climate zones. Genetic studies are hampered by slow growth, lacking sexual cycles and difficulties to transform these fungi. Recently, we implemented CRISPR/Cas9-based genetic tools enabling efficient targeted mutations of the rock inhabitant Knufia petricola (Eurotiomycetes/Chaetothyriales) for studying stress responses, the unusual types of cell division, mineral weathering and symbiotic interactions with phototrophic microbes (Voigt, Knabe et al. 2020, Sci Rep; Erdmann et al. 2022, Front Fungal Biol). To further explore the genome of this fungus as representative of the polyphyletic group of black fungi and to assign functions to yet unknown genes, a forward genetics approach is aimed. We chose the two-component Activator/ Dissociation (Ac/Ds) transposon system from maize for generating a collection of insertional mutants by in-vivo mutagenesis. For the optimal use of this genetic tool, an inducible promoter for the expression of the Ac transposase and by this the regulatable transposition of the resistance cassette-containing Ds transposon is requested. However, endogenous promoters for nitrate assimilation and galactose catabolism that are often used in fungi for regulatable gene expression are not inducible by their substrates in K. petricola suggesting that the regulatory networks for nutrient acquisition differ significantly in the oligotrophic black fungi. Therefore, the metabolism-independent Tet-on system was adopted and validated using a Ptet::gfp construct. No GFP fluorescence was detected in absence of the inducer doxycycline (DOX) while fluorescence intensities increased with increasing inducer concentrations. Consequently, the Tet-on system is suitable for regulatable expression of endogenous and foreign genes in K. petricola.
Biocides, including disinfectants and antimicrobial surfaces (AMCs), are important to prevent the spread of pathogens and antimicrobial resistant bacteria via surfaces. However, concerns have been raised about the evolution and selection of resistance against disinfectants and AMCs. In turn, resistance against disinfectants and AMCs can be associated to antibiotic resistance due to cross-resistance and co-resistance. We need to understand the mechanisms and risks of disinfectants and AMCs for resistance and cross-resistance evolution to optimize their application and safeguard their long-term efficacy. We used adaptive laboratory evolution (ALE) experiments based on repeated exposure of bacteria to disinfectants. Our results show that repeated disinfection of E. coli with benzalkonium chloride in suspension results in a 2000-fold increase in survival within 5 exposure cycles. Adaption is linked to the initial presence of persister cells highly tolerant to benzalkonium chloride. We used the same approach to develop standardizable ALE experiments to determine resistance evolution to AMCs. The results highlight rapid adaptation of E. coli and P. aeruginosa towards copper surfaces. Moreover, there are multiple situations in the clinic or in the environment in which biocides and antibiotics co-occur and in which combination effects can shape their antimicrobial activity or their selective effects. Our work with P. aeruginosa shows prevalent combination effects of biocides and antibiotics, ranging from synergy to antagonism and resulting in the selection for or against antibiotic resistant strains. The combination effects are dependent on the biofilm mode-of-growth, manifesting in apparent differences in the structural arrangement of antibiotic sensitive and resistant strains in biofilms exposed to combinations. Furthermore, biocides affect rates of mutation and horizontal gene transfer, thereby having a potential facilitating effect on resistance evolution. Taken together, our work shows that the role of biocides as potential drivers of resistance evolution and selection deserves further study and regulative action.
A series of field exposure tests according to ISO 9223 up to 9226 was carried out at different locations to determine the corrosivity and the corrosion progress of different test sites throughout northern and eastern Germany. Standard test specimens of steel, zinc, copper and aluminium were exposed to rural, city and marine atmosphere at test sites of the Bundesanstalt für Materialforschung und -prüfung (BAM). Test sites at city atmosphere comprised exposure on a rooftop, next to a highly frequented road and directly at a motorway. Exposure under marine conditions was carried out at Heligoland in the North Sea. The specimens were stored under sheltered and unsheltered conditions on each test site, respectively. Corrosion rates after the first year of field exposure were determined and used for the classification of the atmospheres and the test sites regarding the corrosivity category.
Results after the first year of exposure were presented at the EUROCORR 2018 in Cracow. The current presentation will present an update of results of the systematic study after five years of exposure. The corrosion progress and the mass loss of the standard metals steel, zinc, copper and aluminium will be presented and discussed with respect to the atmospheric conditions and the time of wetness at the test sites. In addition, the difference between sheltered and unsheltered conditions will be discussed.
Aim. The European biocidal products regulation requires environmental risk assessments for biocidal products under service conditions. This is only possible, if processes that lead to biocide emissions into the environment are understood and can be reasonably predicted.
Actual emissions due to leaching result from different processes that are affected by material properties and environmental conditions. Transformation of biocides can affect emissions considerably.
Leaching and possible transformation of the film preservatives carbendazim, diuron, OIT and terbutryn in paints was observed under laboratory and field conditons in order to investigate the influence of different factors, e.g. water contact and radiation on biocide emissions. The paints contained either white titanium dioxide or a red iron oxide pigment to check whether pigments affect leaching processes.
Methods. Test specimens of a water-based styrene acrylic dispersion paint on glass were exposed to UVA-radiation in a UV weathering device and/or exposed to water contact by immersion events on the basis of the European standard EN 16105. Plywood panels were coated and exposed to natural weather conditions in a semi-field experiment. Concentrations of biocides and transformation products were analysed in leachates from laboratory tests, runoff samples and remaining coatings.
Results. The impact of weathering conditions on transformation processes differs for the investigated active substances. Water contact, radiation as well as pigments in the paints determine the pattern and amount of transformation products on coatings, leachates and runoff water. Observations from laboratory and field experiments were compared. It proved that results from laboratory tests support understanding of data from field experiments.
Detailed knowledge on the fate of active substances under environmental conditions supports manufacturers to develop safe applications of film preservatives and authorities to evaluate its environmental impact.
Fungi that share light-flooded habitats with phototrophs may profit from their excess photosynthetic products. But to cope with sunlight-associated stresses [e.g. high temperatures, UV radiation with associated DNA damage, accumulation of reactive oxygen species (ROS), desiccation and osmotic stresses] it is important for fungi to accurately sense and respond to changes in light. The genomes of black [dihydroxynaphthalene (DHN) melanin-containing] fungi from phyllosphere and exposed solid surfaces contain multiple photoreceptors (PRs). The plant pathogen Botrytis cinerea (Leotiomycetes) has a highly sophisticated photosensory and signalling system that helps to avoid light and to locate susceptible hosts. Rock-inhabiting Dothideomycetes and Eurotiomycetes including Knufia petricola possess equal numbers of PRs along with the same set of protective pigments. This similarity between black fungi from plant and rock surfaces suggests that photoperception and -regulation are important for fungi that receive nutrients through cooperation with phototrophs.
Sunlight is an important environmental factor is almost all ecosystems by being a source of energy, information, and stress. All organisms must protect themselves from the harmful effects of light such as UV radiation, ROS accumulation, heat, and desiccation. Finally, light qualities and quantities can be used for decision making, timing and as guide for directed growth when they are sensed and transduced into intracellular signals. Botrytis cinerea and other plant pathogens infecting the sun-exposed parts of the plant must cope with the high light conditions the host plant seeks. Further they experience an altered light spectrum (‘green gap’) when they colonize shaded parts of the plant; it is depleted for blue and red light that is absorbed by the plant chlorophyll and enriched for green and far-red light that is reflected or transmitted by the plant tissue. As these ambient light conditions trigger the shade avoidance response in the plant, the pathogens may trigger their own ‘shading response’ such as the upregulation of virulence determinants and inoculum production. B. cinerea maintains a highly sophisticated light signaling machinery that senses different light qualities to trigger a variety of responses, that are protection, morphogenesis, positive and negative tropisms, and entrainment. These characteristics render B. cinerea a valuable model to enlighten the role of light in parasitic fungus-plant interactions and beyond. The vegetative mycelium – the core of all infection and developmental programs – is not visibly pigmented and thus considered to be sensitive to biotic and abiotic stresses. However, the vegetative hyphae have a very limited half-life and are usually restricted to the invasive growth phase in which they are protected from light by the plant tissue. Fast colonization of host tissues and by this proper nutrient acquisition enables the rapid formation of long-lasting reproduction structures (melanized conidiophores with conidia, sclerotia) on the surfaces of rotted plant tissues. Depending on the light and temperature conditions, conidiation or sclerotial development is initiated. Taken together, B. cinerea uses light-regulated signaling networks to avoid light whenever possible; for example, by minimizing the half-life of sensitive cells that are hiding in plant tissues and by scheduling critical steps such as conidiogenesis, conidial germination and penetration of plant tissues for the night.
Microbiologically Influenced Corrosion of Cast Iron Containers for High-Level Nuclear Waste Disposal
(2022)
Ductile and corrosion resistant cast iron is investigated as a potential container material to store high-level nuclear waste (HLW) in deep geological repositories (DGR) in claystone bedrock. The dynamic corrosion process is dependent on the conditions present in the DGR which are influenced and/or controlled by geochemical parameters (e.g., redox potential, pH, presence of and ionic concentration in (pore-)water), physical parameters (e.g., pressure), and the influence of metabolically active microorganisms. Cast iron corrosion will occur at the intersection of container and its decontaminable coating with the bentonite backfill material which contains natural microbial populations.
The conditions in a DGR are simulated in microcosm experiments to investigate the impact of microbiologically influenced corrosion (MIC); the microcosms contain: B27 bentonite, synthetic pore water, N2 or N2-CO2 atmosphere, cast iron coupons, as well as the bacterium Desulfosporosinus burensis (isolated from repository depth in Buré, France). Three coupon configurations will be used: untreated, coated with decontaminable coating, and coated with decontaminable coating which has been damaged to simulate possible damages. The microcosms will be examined for bio- and geochemical parameters, such as pH, redox potential, mineral phases, sulphate concentration, Fe(II):Fe(III), changes in microbial populations, and the corrosion process for formation of corrosion products, and potential microbial influence, after a 270-day incubation period at 25°C under anaerobic conditions. In subsequent experiments, the sorption behavior of lanthanides and actinides onto the membranes of viable cells and spores of D. burensis, as well as the surface of corroded cast iron coupons will be investigated.
The overall interest in nanotoxicity, triggered by the increasing use of nanomaterials in the material and life sciences, and the synthesis of an ever increasing number of new functional nanoparticles calls not only for standardized test procedures1,2 and for efficient approaches to screen the potential genotoxicity of these materials, but also for standardized and validated methods for surface analysis.
4,5 The analysis and quantification of surface chemistry is hence in the focus of an increasing number of standardization organizations and interlaboratory comparisons with different analytical methods are being done.5 For the monitoring of nanomaterial synthesis and the fast assessment of the number of functional groups such as carboxyl and amino functionalities, which are very commonly used functionalities in the life sciences, simple and validated methods are needed that can be performed with common laboratory instrumentation. 5,6 Here we provide a brief overview of the ongoing research in division Biophotonics employing quantitative NMR (qNMR), conductometry, and colorimetric and fluorometric optical assays for the determination of the total and the accessible number of carboxyl and amino groups on differently sized polymer and silica nano- and microparticles.5-7
Using nanofiber-like cell appendages, secreted proteins and sugars, bacteria can establish initial surface contact followed by irreversible adhesion and the formation of multicellular biofilms. Here, the stabilizing extracellular biofilm matrix together with physiological changes on the single cell level leads to an increased resilience towards harsh environmental conditions, antimicrobials, the host immune response and established cleaning procedures. Persistent microbial adhesion on e.g., medical implants, in water supply networks or food-processing industry is often associated with chronic inflammation, nosocomial and foodborne infections, enhanced biofouling and product contamination. To prevent persistent microbial colonization, antibacterial surface strategies often target the initial steps of biofilm formation and impede adhesion of single cells before a mature biofilm is being formed. While chemical coatings have been widely used, their restricted biocompatibility for eukaryotic cells and attenuated antibacterial-effects due to compound release limit their areas of application and alternative strategies focus on modified surfaces topographies to impede bacterial adhesion. In this work, we used ns-UV laser treatment (wavelength 248 nm and a pulse duration of 20 ns) to generate laser-induced periodic surface structures (LIPSS) with different submicrometric periods ranging from ~210 to ~610 nm on commercial poly(ethylene terephthalate) (PET) foils. Following structurally and chemically analyses, PET samples were subjected to bacterial colonization studies with Escherichia coli TG1, a bacterial test strain with a strong biofilm formation capacity due to the formation of nanofiber-like cell-appendages (pili). Bacterial adhesion tests revealed that E. coli repellence decisively depends on the spatial periods of the LIPSS with the strongest reduction (~91%) in cell adhesion observed for LIPSS periods of 214 nm. Scanning electron microscopy and additional biofilm studies using a pili-deficient E. coli TG1 strain revealed the importance of extracellular appendages in the bacterial repellence observed here, thus, pointing out new antibiotics-free strategies for antibacterial surfaces by impeding nanofiber-mediated bacterial adhesion.
The processing of laser-induced periodic surface structures (LIPSS) represents a simple and robust way for the nanostructuring of solids that allows creating a wide range of surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. While the currently available laser and scanner technology already allows surface processing rates at the m2/min level, industrial applications of LIPSS are sometimes hampered by the complex interplay between the nanoscale surface topography and the specific surface chemistry. This typically manifests in difficulties to control the processing of LIPSS and in limitations to ensure the long-term stability of the created surface functions. This presentation aims to identify some unsolved scientific problems related to LIPSS, discusses the pending technological limitations, and sketches the current state of theoretical modelling. Hereby, it is intended to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry.
Commercially available carbon steels are suitable for compression and pipelines as long as moisture content and impurities are limited. (water 50 to 100 ppmv, SO2 and NO2 ca. 100 ppmv) Corrosion rates increase with increasing water content. (0.2 – 20 mm/a) Condensation of acids and therefore droplet formation is always possible, even at low water contents. A low SO2 content within the CO2-stream might be more important than a low water content. Cr13-steels showed a general susceptibility to shallow pitting and pitting. So, they seem to be not suitable for CCUS applications. Low alloyed steels showed better corrosion behavior (predictable uniform corrosion). For direct contact with saline aquifer fluids only high alloyed steels shall be used.
The exposure to antimicrobial substances drives the evolution of antimicrobial resistance. Biocides are antimicrobials used as disinfectants, antiseptics and preservatives. They find application on a large scale in the industrial and medical sector, but also in private households. In terms of mass, the worldwide use of biocides exceeds that of antibiotics. Thus, despite their important role in preventing the spread of pathogens, due to their ubiquity, biocides are suspected to be drivers of the antimicrobial resistance crisis. In our work at BAM we try to understand how biocides contribute to the emergence of AMR, what the underlying adaptation principles and mechanisms are and how they compare to those found for antibiotics. Within our group, I mainly focus on the following two questions: How does phenotypic heterogeneity in bacteria affect the ability to survive treatment with biocides? And what are the consequences of phenotypic heterogeneity for the evolution of resistance to biocides and antibiotics?
I will share published and unpublished results which demonstrate that phenotypic heterogeneity can enable the survival of biocide treatment and, through this, facilitate the evolution of AMR. On the other hand, we find that adaptation to a biocide can unexpectedly impair the ability to evolve resistance against an antibiotic.
Black fungi also called black yeasts, rock-inhabiting fungi or microcolonial fungi are a group of Ascomycetes [Eurotiomycetes, Arthoniomycetes and Dothideomycetes] that exhibit high stress tolerance, yeast‑like or meristematic growth, and constitutive 1,8-dihydroxynaphthalene (DHN) melanin formation. They dominate a range of hostile natural and man‑made environments – from desert rocks and salterns to dishwashers, roofs, and solar panels. Due to their slow growth and the lack of sexual cycles and genetic tools, the underlying mechanisms of black fungi’s phenotypic traits have remained largely unexplored. We consider the rock inhabitant K. petricola [Eurotiomycetes, Chaetothyriales] a suitable model for studying the phenotypic characteristics of black fungi. With K. petricola the regulation of pigment synthesis, general stress responses and the unusual modes of cell division can be dissected by advanced reverse and forward genetics approaches. The genome of K. petricola strain A95 was sequenced using a combination of short high quality Illumina reads and long PacBio reads. The final assembly consists of twelve contigs: five complete chromosomes and six contigs with one telomer each. Gene annotation supported by transcriptomics and proteomics data was manually curated. Recently, we developed a set of genetic tools to manipulate the genome for analyzing gene functions and studying the cell biology. This set includes CRISPR/Cas9-based genome editing and live-cell imaging using genetically encoded fluorescent proteins, as well as protocols for -omics approaches and for simulation of mineral weathering in the laboratory. Mutants defective in DHN melanogenesis, carotenogenesis or both processes are currently studied to elucidate the role of these protective pigments in tolerance of natural and man-made stresses, weathering of olivine, penetration of marble, and adhesion to surfaces. Further, the established protocols and knowledge gained from K. petricola form a starting point for making other extremotolerant black fungi accessible to genetic manipulation.
Bei Betrachtungen zur Lebensdauer von Metallbauteilen im Bauwesen müssen Korrosions- und Runoff-Vorgänge an der Atmosphäre als verschiedene Reaktionen unterschieden werden. Korrosion ist der Prozess, der von elektrochemischen Reaktionen an der Grenzfläche Metall/Patina kontrolliert wird. Runoff dagegen wird durch chemische Reaktionen an der Grenzfläche Patina/Atmosphäre begünstigt. Mit zunehmender Bewitterungszeit nimmt die Korrosionsgeschwindigkeit stetig ab, während postuliert wird, dass die Geschwindigkeit des Runoffs über die gesamte Zeit konstant bleibt. Dieses Verhalten des Runoffs muss aber zunehmend bezweifelt werden. Die Gesamtmenge an abgezehrtem Metall beinhaltet zwei Bestandteile. Ein Teil wird in die Schicht aus Korrosionsprodukten eingebaut, der andere wird aufgrund von Niederschlägen aus der Patina gelöst. Aus diesem Grund ist die Menge an Zink-Runoff stark abhängig von den Eigenschaften der Korrosionsprodukt- bzw. Patinaschicht und nicht anhand der Zusammensetzung des Metalls abschätzbar. Vorhandene Modelle können die Menge an Runoff, und damit verbunden die Abzehrung einer Schicht aus Zink und Kupfer, sowie den resultierenden Eintrag von Schwermetallionen in die Umwelt nicht mehr darstellen und erklären. Um den Korrosionsschutz an Bauwerken zum einen dauerhaft unter Beachtung von Kostenaspekten und Ressourcenschonung und zum anderen unter ökologischen Gesichtspunkten auslegen zu können, müssen deshalb neue wissenschaftliche Grundlagen erarbeitet und die Mechanismen beschrieben werden.
Das BAM-Forschungsvorhaben RUNOFF widmet sich den Fragestellungen. Der Vortrag gibt einen kurzen Überblick zum Forschungsvorhaben.
Mit dem stetigen weltweiten Anstieg der Nachfrage nach Polymerprodukten nimmt auch die potenzielle Menge an Kunststoffabfällen in der Umwelt zu. Problematisch ist, dass viele der wirtschaftlich relevantesten Kunststoffe sehr lange brauchen, um in der Umwelt abzubauen, sich dort akkumulieren und in kritisch betrachtetes Makro- und Mikroplastik zu zerfallen. Auf der Grundlage des Vorsorgeprinzips fordert die Europäische Kommission daher die Entwicklung neuer polymerer Materialien, die diesem Problem der Persistenz entgegenwirken und unter natürlichen Umweltbedingungen schneller abgebaut werden können. 1,2
Um dieses Problem anzusprechen, wurden mittels additiver Fertigung Polymerblends aus photooxidationsempfindlichem Polystyrol (PS) und hydrolyseempfindlicher Polymilchsäure (PLA) hergestellt. Die Hypothese war, dass sich die beiden Thermoplaste aufgrund ihrer unterschiedlichen Abbauprozesse gegenseitig in ihrem Abbau unterstützen, wenn sie unter moderaten, realitätsnahen Umweltalterungsbedingungen (45 °C) abwechselnd der Photooxidation und Hydrolyse ausgesetzt werden.
In der Praxis zeigten die Ergebnisse, dass die Degradation von PLA durch die Anwesenheit von PS deutlich beschleunigt worden ist – wohingegen die Degradation von PS gehemmt wurde. In diesem Vortrag werden die detaillierten Ergebnisse der Oberflächen- (ATR-FTIR, REM) und Bulk-Analysen (DSC, TGA, FTIR-Transmission, TED-GC/MS) der Blends sowie ergänzende Mikroplastik-Ergebnisse des umgebenden Wassermediums (TED-GC/MS) erörtert.
(i) Überblick zum aktuellen Stand der Normung und aktuellen Normungsvorhaben im Bereich Ökodesign.
(ii) Vorstellung des Forschungsprojektes (Steigerung der produktbezogenen Energie- und Ressourceneffizienz) vor allem in Hinblick auf Vorhaben die sich auf die Langlebigkeit, Reparierbarkeit und Recyclingfähigkeit.
In recent years, the demand for new and sustainable products has been constantly rising. Especially cementitious materials are known for their high carbon footprint and novel approaches will be needed to counterbalance that. The BAM departments 7.1 (building materials) and 4.0 (Material and the environment) try to improve the sustainability of concrete panels by establishing a biofilm on the weather protection layer. Using an ultra-high-performance-concrete allows the production of very thin facade tiles with a small carbon footprint. Furthermore, the durability of these tiles is expected to surpass the one of “normal” concrete facades and offer the possibility of modular renewing of defective tiles instead of a wall, or even remodeling a whole building. The controlled application of biofilms on facades aims to improve biodiversity, microclimate, and air quality in cities. Furthermore, the greening of typically gray surfaces could improve the mental health of the residents. The project focuses on testing a multiplicity of concrete samples, varying e.g., in roughness or pH. The bioreceptivity is analyzed via laboratory tests, as well as in perennial outdoor experiments.
In dieser Präsentation wurden dem Beirat Umwelt die High-Lights und der weitere Ausblick des Foresight Process MIC vorgestellt. Im Fokus stehen hierbei insbesondere die neu angelaufenen Projekte:
COST Action Euro-MIC
MIC im Endlager
Hydrogen: MIC & Wasserstoffversprödung
Biorezeptivität von Betonoberflächen
Mitigation schwarze Pilze
WIPANO ResTest
Phenotypic heterogeneity in disinfection: sources and consequences for antimicrobial resistance
(2022)
A summary of projects here at BAM which investigate the influence of phenotypic heterogeneity on the outcome of disinfection and the influence on antimicrobial resistance. This presentation was given in the Theory Seminar of the Quantitative and Theoretical Biology group of Prof. Oliver Ebenhöh at HHU Düsseldorf
The role of methanogens in microbiologically influenced corrosion (Mi-MIC) is often neglected, due to 1) low reported corrosion rates and 2) the suspected corrosion product siderite, which is electrically non-conductive. Typically, MIC corrosion studies are carried out using batch cultures, which did not represent the dynamic conditions, i.e. pipeline and provide insufficient information on the overall corrosion potential.
We established a unique approach, a multiport flow column (MFC), to simulate pipeline conditions and obtained 10-times higher corrosion rates than previously published. Our result showed that testing procedures have a large impact on the corrosive potential of methanogens. We found strong indications with a combination of ToF-SIMS, SEM-EDS and FIB-SEM analyses that siderite is not the sole corrosion product. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of other environmental parameters (e.g. pH) on Mi-MIC.
Microbiologically influenced corrosion (MIC) is a now well-known challenge and affects industry, society and infrastructure. For a long time, the impact of methanogen-induced MIC (Mi-MIC) was underestimated. This was mainly due to the rather low published corrosion rates and the presumed corrosion product siderite, which is not electrically conductive. In our laboratory, we were able to show that this trivialization or underestimation of Mi-MIC was due to the nature of the testing. The static systems used so far do not provide environmentally relevant information about the corrosion rate and the corrosion product, especially for methanogens
To further illustrate the importance of the environment on the MIC process, we established a multiport flow column (MFC), to simulate the natural environment. With this method, and in contrast to published results using the static conditions, we obtained ten times higher corrosion rates. We analyzed the corrosion products with a combination of techniques, like ToF-SIMS, SEM-EDS and FIB-SEM, and found strong evidence that siderite is not the sole corrosion product of Mi-MIC. The corrosion layers contain phosphorus, oxygen, magnesium, calcium and iron and lacked on carbon-related species. It is hypothesized that methanogens may have influenced the nucleation process of siderite, converting bicarbonate into carbon dioxide for methanogenesis. This results in increased localized corrosion and reduced siderite formation. To verify and deepen our understanding of Mi-MIC, we are currently studying the influence of additional environmental parameters (e.g. pH, salinity, flow rate etc.) on Mi-MIC and the subsequent impacts on corrosion rates and the corrosion products.
Overall, results of this study will expand the current understanding of MIC from both analytical and mechanistic points of view, thus aiding the development of different mitigation strategies for various industry sectors.
Corrosion is a very expensive and serious problem in the different industry sectors, eg. Petroleum-, On- and off-shore, infrastructure. It is estimated that 20% of all corrosion damage is caused by microorganisms or microbiologically influenced corrosion (MIC). Several microorganisms are known to cause corrosion, including sulfate-reducing bacteria, nitrate-reducing bacteria, methanogens etc. For several years, methanogens were regarded as a mild corroder (~0.065 mm/yr), largely due to a lack of detailed investigation on the corrosion mechanism under real-environment simulated conditions. Resulting in the common belief that siderite, a non-conductive compound, is the sole corrosion product (CP) of methanogen-induced MIC (Mi-MIC).
To simulate natural environmental conditions, we developed and introduced the multiport flow column system (MFC), a multi-sectional corrosion flow-cell. Using the MFC, we obtained ten times higher corrosion rates than previously reported. With a combination of several analytical techniques, such as ToF-SIMS, SEM-EDS and FIB-SEM, we found strong indication that siderite is not the sole corrosion product of Mi-MIC. The corrosion layers contained phosphorus, oxygen, magnesium, calcium and iron. The differences in the CP between static and dynamic environments demonstrated the impact of testing procedures on the corrosive potential of methanogens. To further verify and deepen our understanding of Mi-MIC, we are currently studying the influence of additional environmental parameters (e.g. pH, salinity, flow rate) on Mi-MIC.
Overall, results of this study will expand the current understanding of MIC from both analytical and mechanistic points of view, thus aiding the development of different mitigation strategies for various industry sectors.
Der Fachbereich 7.6 untersucht seit einiger Zeit an Auslagerungsständen auf dem Testgelände in Horstwalde Korrosion im maritimen Bereich. Im Moment läuft das System mit künstlichem Meerwasser und simuliert die Bewitterung von Metallproben unter angenäherten klimatischen Bedingungen ähnlich zum natürlichem Habitat. Im Laufe der Zeit konnte nicht intendierter mikrobieller bewuchs beobachtet werden. Es stellte sich die Frage, welche Mikroorganismen vorlagen und ob diese einen Einfluss auf die Korrosionsuntersuchungen haben könnte. Aus diesem Grund wurden 16S-rRNA Untersuchungen durchgeführt welche alle drei Domänen des Lebens widerspiegeln Bakterien, Archaea und Eukaryoten. Es konnte gezeigt werden, dass über 95% der vorliegenden Biomasse Grünalgen waren, die durch Licht Eintrag in den Container Photosynthese betrieben und dadurch an Biomasse zunahmen. Des weiteren konnten Bakterien detektiert werden, welche in der Regel halophilen und aeroben Habitaten zu finden sind. Allerdings wurden auch Sulfat reduzierende Bakterien (MIC) detektiert, wenn auch in einem geringen prozentualen Anteil. Es muss allerdings Berücksichtigt werden, dass die mikrobielle Zusammensetzung sich im Laufe der Zeit weiter ändern kann. Als Ursprung der Biomasse wird, das künstliche Sediment vermutet. Außerdem wäre es für zukünftige Experiment denkbar, das System mit echtem Sediment aus dem marinen Habitat anzuimpfen.
Der konstruktive Leichtbau erfordert den zunehmenden Einsatz hochfester Feinkornbaustähle mit Streckgrenzen bis zu 1300 MPa. Um darüber hinaus Schweißzeit, Schweißnahtvolumina und Schweißkosten zu minimieren, kam es zur Entwicklung moderner Lichtbogenprozesse mit erhöhter Abschmelzleistung, wie bspw. dem modifizierten Sprühlichtbogen. Das Schweißen mit modifiziertem Sprühlichtbogen bietet die Möglichkeit, schmalere Nahtfugen bzw. kleinere Nahtöffnungswinkel zu schweißen. Mit zunehmender Festigkeit der Baustähle steigen allerdings die Anforderungen an die schweißtechnische Verarbeitung. Hochfeste Feinkornbaustähle weisen ein erhöhtes Risiko gegenüber der wasserstoffunterstützten Kaltrissbildung auf. Diese Werkstofftrennungen entstehen unter gemeinsamer Wechselwirkung von lokalem risskritischem Gefüge, lokal erhöhter Wasserstoffkonzentration und lokal erhöhter Beanspruchung bzw. Dehnung. Untersuchungen haben gezeigt, dass der Einsatz des modifizierten Sprühlichtbogens in Verbindung mit schmalen Nahtfugen zu erhöhten Wasserstoffkonzentrationen im Schweißgut führt. Die vorliegende Arbeit gibt einen Aufschluss hinsichtlich der Kaltrissempfindlichkeit des vergüteten, hochfesten Feinkornbaustahls S960QL anhand der durchgeführten Kaltrissprüfung mittels selbstbeanspruchenden TEKKEN-Tests. Dazu wurden die Nahtöffnungswinkel der Prüfnähte zwischen 30° (Einsatz des modifizierten Sprühlichtbogens) und 60° (Einsatz des konventionellen Übergangslichtbogens) variiert. Ferner wurde die Wirksamkeit einer Nachwärmprozedur aus der Schweißwärme heraus zur Vermeidung der wasserstoffunterstützte Kaltrissbildung untersucht. Die Ergebnisse weisen in allen Proben (ohne Nachwärmung) Kerbrisse auf, welche als Kaltrisse identifiziert werden konnten. Durch eine Nachwärmung unmittelbar nach dem Schweißen können diese gänzlich vermieden werden. Das Schweißgut mit modifizierten Sprühlichtbogen weist die höchsten mittleren Wasserstoffkonzentrationen auf. Ferner zeigt das Schweißgut unter reduziertem Nahtöffnungswinkel eine vermehrte Mikrorissbildung auf.