TY - THES A1 - Richter, Sebastiaan T1 - The influence of lime, iron sulphate-lime mixtures, and iron compounds on bioavailable phosphorous N2 - Available nutrients for higher plants in the soil are crucial in agriculture and can be repressed by farming practices. The objective of this thesis was to determine if the application of a lime-FeSO4 mixture reduces the available phosphorus for higher plants further than conventional liming. For this, soils from the Lower Rhine region in Germany with different soil properties were collected, treated with different applications, and incubated over a predefined time. Aerobic and anaerobic conditions were created by raising the soils’ water content to 50% and 100% of their maximum water holding capacity. Bioavailable phosphorus was extracted from the incubated samples with the Calcium-acetate-lactate (CAL) method, and analysed in the Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Statistical analysis was conducted with the open-source program “R for statistical computing”. Results showed that not the treatment but rather the type of soil had a significant effect on the phosphorus availability. At some extent the WHC significantly influenced the phosphorus availability. In general, lime-FeSO4 mixtures showed a tendency to have higher phosphorus availability than conventional liming. Effects of long-term field application cannot be determined because the experiment was conducted under laboratory conditions for a limited time. For farming, further field experiments and monitoring of fields where the lime-FeSO4 mixtures are regularly applied can exclude negative long-term effects and determine sufficient the effect of lime-FeSO4 mixtures on bioavailable phosphorus. KW - Phosphorus KW - Liming KW - Bioavailability Y1 - 2018 ER - TY - THES A1 - Nidola, Marta T1 - Frass upcycling: study on the properties of frass and its use as fertilizer and soil amendment in agriculture N2 - Frass, as by-product of the emerging insect market, has been used as fertiliser worldwide. However, the impacts on soil microbial community structure and activity have been not yet well characterized. The aim of this study was to assess the effects that frass from black soldier fly reared on 3 different diets may cause when applied fresh and dried (70°C) on a sandy loam soil, in 2 application rates (0.2 and 2% w/w). For that, frass was chemically characterized before a 28-days incubation, at the end of which samples were analysed from the chemical and biological point of view. It was found that thermal treatments and diets didn’t vary significantly in microbiota stimulation, even though a chemical analysis would suggest the potential for enriched-frass from pig effluent and wheat bran to encourage microorganisms differently from beer & coffee diet. Furthermore, fresh frass contrarily to what expected didn’t contribute with living microorganisms to enhance microbial activity and growth. However, a difference was reported for the application rates, with the 2% leading to more mineralisation than control. A trend for 2% dried frass from B&C was found, indicating the establishment of an efficient community of fungi slowly mineralizing recalcitrant and exhausted frass. Results indicate that more studies testing application rates ranging between 2 and 2.5% have to be conducted. In fact, there is evidence that BSFF between the mentioned application rates could enhance a fast microbial growth leading to a substantial mineralisation of frass, thus availability of nutrients in the short and long term. Y1 - 2021 ER - TY - THES A1 - Rademacher, Marian Evelin T1 - Entwicklung eines Modells zur Untersuchung des Einflusses von präbiotischen Wirkstoffen und Konservierungsmitteln auf das Hautmikrobiom N2 - Der gezielte Einsatz von präbiotischen Wirkstoffen in kosmetischen Produkten, zur Verbesserung des Hautbildes mittels Beeinflussung des Hautmikrobioms, wird zunehmend verfolgt. Das Gleichgewicht der residenten Bakterien auf der menschlichen Haut ist sowohl für die äußere Erscheinung als auch für die Gesundheit von großer Bedeutung. Mittels Anwendung des präbiotischen Wirkprinzips, bekannt aus dem Lebensmittelbereich bezüglich spezifischer Förderung des Darmmikrobioms zur Verbesserung des Immunsystems, werden pathogene Bakterien im Wachstum gehemmt und positive Bakterien gefördert. Die Übertragung des Wirkprinzips, von sowohl Präbiotika wie auch Postbiotika, vom Lebensmittel- in den Kosmetikbereich findet zunehmend statt. Es besteht die Notwendigkeit die Wirkungsweise der Wirkstoffe zu verstehen und geeignete Untersuchungsmethoden bezüglich der Prüfung der Wirksamkeit anzuwenden. Zielgebend der Forschung der vorliegenden Arbeit ist die Entwicklung eines geeigneten in- vitro Modells zur Prüfung der Wirksamkeit einzelner präbiotischer bzw. postbiotischer Wirkstoffe, eingearbeitet in verschiedenen Formulierungsarten. Zusätzlich gilt es herauszufinden inwiefern Konservierungsmittel Einfluss auf das Hautmikrobiom ausüben. Die Herausforderung besteht darin eine Oberfläche, als geeignetes Äquivalent zur menschlichen Haut, zu finden, auf der die Formulierungen aufgetragen und verglichen werden können. Zur Entwicklung eines geeigneten Modells wurde mittels Modifikation und Behandlung von einzelnen Lederwaren die Wirksamkeit von prä- und postbiotischen Wirkstoffen untersucht. Aus dem Leder wurden, aus insgesamt sieben residenten Bakterien, verschiedene bakterielle Träger erstellt. Auf den Trägern wurden drei verschiedene präbiotische Wirkstoffe, in Kombination mit einem Konservierungsmittel, in verschiedenen Einsatzkonzentrationen und Auftragsmengen mit einer Einwirkzeit von 30 min appliziert. Als Vergleich wurden die Wirkstoffe als Rohstoff mittels Screening- Verfahren bezüglich ihrer Wirksamkeit geprüft. Die Ergebnisse zeigen, dass durch Anwendung des Modells das Wachstum der Bakterien durch die in den Formulierungen enthaltenden Wirkstoffe beeinflusst wird. Durch Variation der Einsatzkonzentrationen, Auftragsmengen und Formulierungsarten können unterschiedliche Einflüsse auf das bakterielle Wachstum beobachtet werden. Eine Hemmung der pathogenen und Förderung der positiven Bakterien wurde ersichtlich. Das Modell ermöglicht die Untersuchung prä- und postbiotischer Wirkstoffe, die in Formulierungen eingearbeitet wurden, bezüglich deren Wirksamkeit auf einer hautähnlichen Oberfläche. Für eine Etablierung des Modells sind weitere Versuchsreihen mit einer höheren Variation von Wirkstoffen und Bakterien notwendig. N2 - The specific use of prebiotic substances in cosmetic products, in order to improve skin appearance through influencing the skin microbiome, is increasingly being pursued. The balance of resident bacteria on human skin is of great importance for the external appearance as well as health. By applying the prebiotic mode of action, prominent in the food sector concerning the specific support of intestinal microbiomes to improve the immune system, pathogenic bacteria are inhibited in growth and positive bacteria are supported. This transfer, of prebiotics and postbiotics, from the food sector to the cosmetics sector is increasingly happening. It is key to understand the mode of action of substances and to apply appropriate research methods regarding the testing of efficacy. The objective of the research is the development of a suitable in vitro model in order to test the efficacy of individual prebiotic and postbiotic substances incorporated in different types of formulas. In addition, it is important to clarify the influence of preservatives on the skin microbiome. The challenge is to find a surface, that acts as a suitable equivalent to human skin, on which the formulas can be applied and set-in contrast. In order to develop a suitable model, the effectiveness of pre- and postbiotic agents was investigated by modifying and treating individual leather goods. Out of a total of seven resident bacteria, different leather bacterial carriers were created. At different application concentrations and application rates with an exposure time of 30 min, three different prebiotic agents, in combination with one preservative, were applied to the carriers. Meanwhile, the substances were tested as raw materials by means of screening procedures regarding their efficacy. The results show that through applying the model, the growth of bacteria is influenced by the substances contained in the formulas. Through varying the application concentrations, quantities and formula types, different effects on bacterial growth can be observed. The inhibition of pathogenic and support of beneficial bacteria became evident. The model allows the investigation of pre- and postbiotic agents incorporated into formulas with respect to their efficacy on a skin-like surface. Further series of experiments with a higher variation of substances and bacteria are necessary to establish the model further. Y1 - 2021 ER - TY - THES A1 - Kulms, Leander T1 - Paludiculture and farming practices for carbon storage in peatlands – a case study at the lower Rhine N2 - Moors have fascinated and scared humanity for centuries. Recently, these wetlands are discussed about for their Climate Change mitigation potential by re-wetting efforts. Since most studies on the topic of potential greenhouse gas (GHG) emission reduction in Germany focus on large areas in the North and South of Germany, this study observes a smaller example area of organic soil in Kleve, North-Rhine Westphalia. It is analyzed in terms of suitability for paludiculture as well as for potential savings of GHG and a reduction of the Global Warming Potential (GWP). The study introduces a ranking system that allows an easy estimation of the suitability of fields, based on criteria that assign points from 1 to 4 per criteria. The total for each field is compared with one another. Emission values are based on the GEST-approach, developed by moor scientists in Greifswald, Germany. This study compares current field emissions in Kleve and compares them to theoretical agricultural cultivation scenarios that are simulated and projected onto said fields. The scenarios include the cultivation of Phragmites australis, a grazing system with Bulbalus arnee and the neglection of agriculture supplemented with photovoltaic power harvesting. The research highlights that maintaining high water levels is crucial for significant greenhouse gas emission savings. Water levels of around the soil surface level are assumed to have the highest potential for such savings. Phragmites australis cultivation and the grazing scenario demonstrate the highest potential for savings, reaching up to 2118.56 t CO2-equivalent per hectare annually. Although the findings of this study are promising, it is strongly recommended to update this study with newer findings in the future and to consider production-related emissions that extend the sole on-field emissions. KW - Paludiculture KW - Moor KW - Lower Rhine KW - Organic soil KW - Wetland Y1 - 2023 ER - TY - THES A1 - Khedher, Lara T1 - Evolution of CRISPR-Cas genome editing methods: Chances and challenges in biotechnology N2 - Clustered regularly interspaced short palindromic repeats, CRISPR, are located on DNA sequences, which encode for an antiviral defense mechanism in bacteria and archaea. Together with CRISPR-associated proteins, Cas endonucleases, CRISPR-Cas has emerged into a powerful platform for editing DNA and RNA. This thesis investigates the evolution and function of this prokaryotic defense mechanism and points out the three most applied CRISPR-Cas systems in relation to current applications in biotechnology. Furthermore, chances and challenges of named systems as well as a guideline for choosing the appropriate system with Cas endonucleases is framed. Therefore, several scientific databases were screened for the most informative and influential publications around the topic. Information was collected and organized in a reference management software. The utilized literature was tabularly denoted and gives an overview of the broad scope of CRISPR-Cas. The analysis of the topic shows, that CRISPR-Cas offers a broad application range with a huge chance for genome editing. A conclusion of this thesis is, that CRISPR-Cas has an enormous potential to be implemented for human genome editing. However, its challenges should be cleared beforehand. Further research has to be done to fully understand the impact CRISPR-Cas may have in future. KW - Genome editing KW - Genetics KW - CRISPR KW - Cas Y1 - 2020 ER - TY - THES A1 - Kieroth, Alexander T1 - An optimization approach for the distribution logistics using the example of the Vital Centrum Hodey KG N2 - This thesis analyses how the Travelling Salesman Problem can be solved by applying the Simplex LP and the Evolutionary Algorithm with regards to driven kilometres. Each algorithm is solved by using the Excel Solver add-in provided by Microsoft Excel. The results of the two different algorithms are compared with the results of the route planning software PTV Map&Guide Online for the purpose of having a proof that the software works efficiently. Using a cost analysis, the costs for delivering goods are calculated and compared with an external supplier who acted as the outbound logistics for the company HODEY. Now that the delivery is insourced, the costs can be reduced and HODEY gains more control over the outbound logistics. An approach on how to reduce the stop times at the customers’ homes is analysed. Thus, the analysis provides information regarding where the delivery driver wastes most of their time. Additionally, an available space calculation of the delivery vehicles is carried out for the dispatching department of the company to avoid interim loading or unloading not planned for a delivery or retrieval tour KW - Travelling salesman problem KW - Simplex LP KW - Evolutionary algorithm Y1 - 2020 ER - TY - THES A1 - Maier, Franziska T1 - Komparative Analyse von Literaturdaten und Herstellerangaben zur Effektivität antimikrobiell ausgerüsteter Oberflächen N2 - Die schnelle Ausbreitung von Mikroorganismen wie Bakterien, Pilzen und Viren kann äußerst schädlich sein und zu saisonalen Epidemien führen. Darüber hinaus können diese Mikroorganismen Lebensmittel und wichtige Materialien verunreinigen, was zu erheblichen wirtschaftlichen Verlusten führt. Um die Ausbreitung von Mikroorganismen zu verhindern, ist es wichtig, die Wechselwirkungen zwischen verschiedenen Mikroben und Oberflächen zu verstehen, die zu deren Anhaftung und Wachstum führen. Ein solches Verständnis ist entscheidend für die Entwicklung antimikrobieller Oberflächen. In dieser Arbeit werden verschiedene Ansätze und Produkte zu den antimikrobiellen Oberflächen untersucht und Oberflächeneigenschaften mit antimikrobiellen Aktivitäten in Beziehung gebracht und analysiert. Eine Gegenüberstellung der wichtigsten Hersteller von antimikrobiellen Oberflächen und deren Technologien wird durchgeführt und mit aktuellen wissenschaftlichen Studien belegt. Die Übersicht konzentriert sich auf die physikalische und chemische Modifizierung der Oberflächen, um die Benetzbarkeit, die Oberflächentopografie und die Oberflächenladung zu modulieren und so die Adhäsion, das Wachstum und die Vermehrung von Mikroben zu hemmen. Darüber hinaus werden die Anwendungsgebiete von antimikrobiellen Oberflächen dargestellt. Die allgemeinen Erwartungen an eine antimikrobielle Oberfläche sind hoch, da sie die Anhaftung und das Wachstum von pathogenen Mikroben wirksam verhindern und langlebig sind. Sie sollen sicher für Mensch und Umwelt und möglichst kostengünstig sein. Bislang wurde das Design antimikrobieller Oberflächen zumeist nach dem Zufallsprinzip durchgeführt, ohne dass für jede Designstrategie robuste Struktur-Aktivitäts-Beziehungen oder die beabsichtigte Verwendung eines bestimmten antimikrobiellen Materials berücksichtigt wurden. Darüber hinaus werden in der vorliegenden Arbeit die wichtigsten Erkenntnisse der Systeme zur Entwicklung antimikrobieller Oberflächen kritisch diskutiert, ebenso wie die Grenzen der aktuellen Forschung und die Lücke, die noch geschlossen werden muss, bevor diese Ansätze in der Praxis umgesetzt werden können. KW - Effektivität antimikrobiell ausgerüsteter Oberflächen KW - Antimikrobielle Oberfläche Y1 - 2022 ER - TY - THES A1 - Künneke, Felix T1 - The influence of tire wear particles (microplastic) on food security With a focus on agriculturally relevant plant species (Avena sativa L., Brassica napus L. & Zea mays L.) and soil organisms (Aporrectodea caliginosa & Eisenia andrei) N2 - Development and implementation of environmental assessment concepts must gain stronger positions in policy making. This thesis focuses on the influences of currently, widely unregulated microplastic tire wear particle emissions on food security. An overview of global differences in microplastic waste treatments is given. Changes in behavior, law-making and technical innovations are argued to be equally needed to stop the ongoing pollution to prevent negative impacts on ecosystem services as the foundations for food security. In an experimental set-up, three particle size ranges (<125,125-250, 250-500 μm) in three treatment concentrations (0.01, 0.1, 1 %) with a negative control were applied to determine the influence of microplastic tire wear on three arable crop species and two earthworm species. Evenly, for all administrations, no significant effects could be observed on the organisms’ height, biomass, RSR, or body tissue. Nevertheless, the results should not be interpreted as an all-clear signal, as the experiments observed only a few of the vast amounts of microplastic sinks. More data is needed as the EU Commission's recent “call to action” emphasizes. Determination of species resilience factors and traits shall be foci of future investigations to find cofactors for solution strategies. A more precise definition of microplastic and its additives classifications will certainly aid the consensus on priorities in research and consumers' clarity about biodegradability. Y1 - 2022 ER -