Sanitär- und Kommunaltechnik; Umwelttechnik
Filtern
Dokumenttyp
- Posterpräsentation (12)
- Vortrag (10)
- Zeitschriftenartikel (4)
- Beitrag zu einem Tagungsband (1)
- Dissertation (1)
Schlagworte
- Biofilm (28) (entfernen)
Organisationseinheit der BAM
- 4 Material und Umwelt (10)
- 4.0 Abteilungsleitung und andere (6)
- 4.1 Biologische Materialschädigung und Referenzorganismen (5)
- 6 Materialchemie (4)
- 7 Bauwerkssicherheit (4)
- 7.1 Baustoffe (4)
- 1 Analytische Chemie; Referenzmaterialien (2)
- 5 Werkstofftechnik (2)
- 5.1 Mikrostruktur Design und Degradation (2)
- 6.2 Material- und Oberflächentechnologien (2)
Paper des Monats
- ja (1)
Eingeladener Vortrag
- nein (10)
Biochemische und physiologische Charakterisierung der extrazellulären Matrix eines Modellbiofilms
(2018)
An der Grenzschicht zwischen einer festen Oberfläche und der umgebenden Luft wachsende subaerische Biofilme (SAB) zeichnen sich durch eine erhöhte Toleranz gegenüber extremen Umweltbedingungen und dem Eintrag von Bioziden aus. Dieser Schutz vor äußeren Umwelteinflüssen wird vornehmlich durch den Beitrag von extrazellulären polymeren Substanzen (EPS) und Pigmenten, wie Melanin und Carotinoiden, vieler unterschiedlicher Organismen gewährleistet. Deren Synthese wird wiederum durch intrazelluläre Botenstoffe reguliert. Das Cyanobakterium Nostoc punctiforme und der mikrokoloniale Pilz Knufia petricola, als Partner eines etablierten SAB-Modells und Vertreter zweier typischer Organismengruppen in SAB, wurden genutzt, um Botenstoffe und Pigmente genetisch zu manipulieren und die Biofilmmatrix dieser Mutanten strukturell zu untersuchen. In dieser Arbeit konnten erstmals die EPS beider Organismen extrahiert und die Struktur der extrazellulären Polysaccharide beschrieben werden. Daneben wurden die extrazellulären Polysaccharide von K. petricola Wildtyp mit denen verschiedener Pigmentmutanten verglichen. Das Fehlen des Schutzpigmentes Melanin führte zu einer ausgeprägteren extrazellulären Matrix in den Biofilmen. Gleichzeitig änderte sich die Struktur der extrazellulären Polysaccharide. Während der Wildtyp zu ~80% ein α-Glucan und zu ~20% ein α/β-Galaktomannan sekretierte, war der Anteil des Galaktomannans bei den Melaninmutanten erhöht. Das Ausschalten der Carotinoid-Synthese hatte jedoch keinen Einfluss auf die Beschaffenheit der extrazellulären Polysaccharide. Ein deutlich komplexeres extrazelluläres Polysaccharid aus acht verschiedenen Monosaccharid-Einheiten bildete N. punctiforme. Durch die Überproduktion des bakteriellen sekundären Botenstoffes c-di-GMP konnte zudem ein grundlegender Einfluss auf die Reaktion des Cyanobakteriums gegenüber externen Signalen und die damit verbundene Zelldifferenzierung gezeigt werden. Ein artifiziell erhöhtes c-di-GMP-Level in den Zellen führte zur Ausbildung eines sessilen Lebensstils durch Hemmung der Differenzierung motiler Hormogonien und vermehrte Produktion von EPS. Die Struktur der extrazellulären Polysaccharide wurde dadurch nicht verändert. Neben der strukturellen Analyse konnten die Veränderungen der extrazellulären Matrix beider Organismen zusätzlich durch mikroskopische Methoden visualisiert werden. Beide Organismen steuern komplexe Polymere, deren Produktion maßgeblich mit intrazellulären Faktoren verknüpft ist, zu der extrazellulären Matrix des Modellbiofilms bei.
Development and characterization of starch film and the incorporation of silver nanoparticles
(2020)
Starch is one of the biopolymers being used for bioplastic synthesis. For production, starch can be combined with different plasticizers, starches from different plant sources and even with nanomaterials to improve or to add film properties. The challenge of adding these, e.g. in the form of silver nanoparticles (AgNp) is to determine the concentration so as to avoid impairing the properties of the film, agglomeration or altering the visual characteristics of the film. In this study, a starch film synthesis route and the incorporation of silver nanoparticles has been proposed in order not to alter the properties of the film while maintaining the transparency and a clear colour of the starch film. The results showed that the proposed synthesis route is promising, efficient, reproducible, fast and the film has good mechanical properties.
Fungal biofilms on materials: describing and modelling growth of the black fungus Knufia petricola
(2023)
Fungi that grow as biofilms are associated with clinical settings as well as various cases of material fouling and material damage. Black fungi as biofilm formers have been rarely studied so far. Their conspicuous dark pigmentation, EPS production, adhesion capabilities and adaptations to stresses allow black fungi to develop biofilms on materials under harsh conditions. For example, rock-inhabiting black fungi withstand sun irradiation and dehydration and are therefore ubiquitous on arid surfaces like solar panels and marble monuments.
To understand and control their ability to colonise and deteriorate materials, one should assess and model black fungi’s growth patterns. But so far, no mathematical model has been developed to describe their growth. Knufia petricola A95, representing rock-inhabiting fungi from Chaetothyriales, is genetically amenable and can serve as a model for biofilm studies in black fungi. The primary objective of this project is to develop a growth model for K. petricola A95 which will enable to define and predict material colonisation of black fungi.
Dedicated experimental work with K. petricola will allow the quantitative assessment of the impact of environmental conditions (e.g. pH, nutrients, etc.) on the growth behaviour at the biofilm and single cells level. Data which will be used to validate and develop an individual-based model (based on the iDynoMICS modelling platform) that explains how fungal biofilms form, colonise materials, and cause deterioration.
Thus far, research has been conducted on the impact of different concentrations and sources of major elements (e.g. C, N, …), as well as trace elements (e.g. Cu, Mg, …), on the colony shape and biomass of Knufia petricola A95 biofilms. To study the behaviour of single cells, the length of the cell cycle in different growth media has been determined via the combined use of microfluidic devices and confocal microscopy.
Microbiological biofilms on rocks are ubiquitous in nature and their influence on soil formation through rock weathering has been shown (Gorbushina 2007). However, most previous studies on rock weathering are limited to understanding the physical and chemical aspects overlooking the impact of biota. Due to the enormous amounts of variables that come with a biological process, the quantification of its influence is only possible by using well-controlled and simplified laboratory models. Thereby gaining more insight on the impact of rock inhabiting biofilms on mineral weathering. This presentation will show the impact of biotic weathering in terms of olivine dissolution rates
Natural forsterite was incubated in batch reactor flasks with and without a model consortium consisting of the phototrophic cyanobacterium Nostoc punctiforme and the rock-inhabiting ascomycete Knufia petricola, and submerged in a growth solution (pH 6). The flasks were incubated for 30 days under 25°C, 90 µmol photons/m2s and were shaken at 150 rpm. qPCR was performed to quantify the cell number of both organisms, BET to gather the specific surface of the used olivine and ICP-OES to follow up the change of concentration of the leached out metals.
Our results show that our model consortium, especially K. petricola does increase the dissolution rate of olivine. The pH increased from the initial 6 to around 7.2 for all setups. Initially Mg was preferentially released over Si (Mg/Si of 3.5), until after two days the ratio starts equilibrating around stoichiometric dissolution. During this timeframe the dissolution rate drops by nearly two orders of magnitude, just as observed by Daval et al., (2011). The difference in dissolution rates between the different setups is initially non-existent, but increases over time. After 30 days the setup with K. petricola gives a dissolution rate of 1.08 10-13 moles/cm2s, compared to 9.23 10-14 moles/cm2s for the abiotic setup.
We expect this study to cause awareness on the impact of microbiology on mineral weathering. Additionally it is a starting point for other, more complicated experiments using for instance flow through or drip flow reactors or other minerals.
Genetic manipulation of protective pigments in a rock-inhabiting model fungus Knufia petricola A95
(2016)
Sub-aerial biofilms typically form on bare rock. They consist of 99% cell material and extracellular polymeric substances (EPS) metabolising at low water availability. Rock-inhabiting melanised fungi represent an important part of the microbial community in these environments, playing important roles in the colonisation of mineral surfaces, rock weathering and soil formation in the ecological/geochemical context. Different cellular stress responses make rock-inhabiting ascomycetes fit for survival under extremely changing irradiation, as well as water, energy sources and nutrient availability. Melanised, rock-inhabiting fungi possess multiple protective pigments, form facultative symbiotic associations with photobionts and weather minerals. Melanised fungi build a protective layer around the cell that is critical in adhesion to other living partners, for the colonisation of the substrate and in the subsequent damage of the colonised surface. We chose Knufia petricola (Chaetothyriales) as a model species to analyse colonisation of surfaces. The basic physiology of K. petricola strain A95 is studied, its full genome sequence has been prepared for annotation and methods for deleting specific genes have been established. Unique features of K. petricola including the protective pigments (melanin and carotenoids) and EPS/cell wall properties are now being dissected genetically. As K. petricola strain A95 is in the basic clade of Chaetothyriales, it is an ancestor of both important human pathogens including Exophiala and lichens from the Verrucariaceae family. For this reason studies with A95 can help clarify the basis of fungal pathogenicity – as well as explain interactions with microscopic phototrophic partners like unicellular green algae and cyanobacteria. With Knufia petricola we will establish a canon of experimental approaches to characterise and quantify fungi that actively contact inanimate solid materials. The set of methods developed for Knufia will be adapted to heavily melanised and EPS-producing ascomycetes and can be broadly applied to medically important as well as material-colonising fungi.
A new tool in material science - Targeted disruption of melanin synthesis in rock-inhabiting fungi
(2016)
The ability to survive almost absolute dehydration through air-drying is a remarkable feature of rock-inhabiting microcolonial fungi (MCF), which colonise rock surfaces in hot and cold deserts. Understanding of the underlying mechanisms which allow this group of fungi to conquer natural and man-made environments requires a set of modern biological techniques and approaches that are under development in our laboratory. We will present an overview of the targeted disruption of melanin biosynthesis genes in the rock-inhabiting Knufia petricola and give inside into the lines of research and the network of supporting laboratories that made this progress possible.
In the modern world there is an increased understanding that design and performance monitoring of materials have to be tested in connection to chemical, physical and (micro)biological challenges. A systematic study on how biofilms interact with materials and what could be done to engineer biofilms and/or materials in order to maximize the resistance of the material (surface) or the resistance the biofilm-modified material (bulk) is in strong need. In the Department “Materials and the Environment” of the BAM new experimental platform is being developed. With the help of different type of device for high throughput and microbiologically-controlled environment simulation we establish a new approach to clarify the mechanisms of biofilm/material interactions. Despite the focus on fundamental research, the main results of this project proposal will be transferable into material technology and construction chemistry and will influence the development of standardization in this topic. As the interactions of biofilms and materials have implications for most constructions as well as climate change, the results of the research generates additional value.
The story of how black fungi survive harsh conditions on sun-exposed desert rocks and material surfaces is fascinating. In the presentation examples of how knowledge of these organisms can be of practical value (e.g., in biodeterioration studies, such as on stone markers in cemeteries) would be given. Among other stories, the example of how roof tiles amended with a titanium oxide layers as a biocide actually selected for the black fungi will be told. A hypothesis about how these organisms would likely be found on solar panels and some early BAM work in that area will be presented. This then brings the connection to a study ripe for investigation in North Carolina. The talk presents the development of a study aiming at deciphering the influence of microbial biofilm formation on the energy conversion efficiency of solar photovoltaic panels or modules at two facilities (one facility under the impact of high intensity of animal agriculture and high deposition of ammonia from atmosphere and the other with low animal agriculture and lower atmospheric ammonia deposition) in North Carolina. The main hypothesis of the study is that microbial biofilm formation on solar photovoltaic panels will lead to significant decreases in energy conversion efficiency of solar photovoltaic modules and biofilm formation will also be accelerated by high ammonia concentration in the ambient atmosphere and high nitrogen deposition.
Essential processes necessary for the establishment and maintenance of rock biofilms include photosynthesis, production of extracellular polymeric substances, substrate penetration and nutrient enrichment from the atmosphere. This natural functional diversity is supported by a complex biofilm community consisting of heterotrophic and phototrophic microorganisms. While heterotrophic rock biofilm-formers are dominated by stress-tolerant microcolonial ascomycetes, phototrophs might be represented by diverse algae and cyanobacteria. Reduction of model systems to the genetically tractable minimum, a proven successful experimental strategy in different symbiotic systems, is now applied to rock biofilms. These complex and important natural systems are simulated in the lab using genetic methods coupled with continuous microscopic and analytical (microscopic as well as geochemical and biochemical) observations. Our in vitro bipartite model includes free-living and symbiosis-competent, genetically tractable microorganisms – a rock-inhabiting fungus Knufia petricola A95 and a cyanobacterium Nostoc punctiforme strain ATCC 29133. To accurately reflect the development of a rock biofilm, contacts of these two genetically tractable partners are studied under well-controlled laboratory conditions. This experimental strategy is strongly supported by the knockout mutants of Knufia petricola which have been recently created and will be compared in their action on mineral surfaces. An impact of Knufia petricola strain A95 with or without protective pigments on mineral adhesion and alteration will be presented.
Soil formation on weathering rock surfaces is intrinsically connected with the development of primary microbial colonization at the atmosphere-lithosphere interface. A great number and variety of microorganisms is involved in these microbial communities, which are dominated by fungi, algae, cyanobacteria and heterotrophic bacteria. Rock-inhabiting life is ubiquitous on rock surfaces all around the world, but the laws of its establishment, and more important, quantification of its biodeterioration and geological input are possible only in well-controlled and simplified laboratory models. Here we would like to compare two model rock biofilm consisting of the heterotrophic and the phototrophic interacting partners. In the present work the growth of these model biofilms on diverse materials with different physical and chemical properties was investigated under well-controlled laboratory conditions. To clarify the role of environmental factors, the parameters temperature, light intensity and relative humidity were varied in growth test series. For an accelerated substrate colonization and to increase the biomass yield different flow-through chambers systems with semi-continuous cultures have been applied, simulating weathering conditions like flooding, desiccation and nutrient input. The biofilm development was studied by (i) confocal laser scanning and electron microscopy and (ii) qualitatively and quantitatively with respect to cell forms and biomass. A correlation between the presence of the model biofilm and mineral surface alteration as well as geochemical tracers of weathering were followed on various rock substrates (with differing geochemistry, porosity etc) exposed in another flow-through chamber, filled with crushed rock material. Under mentioned environmental conditions different types of flow-through chambers have been used and will be compared.