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The Influence of Microbial Degradation of Biochar in Soil on its Physico-chemical Properties
Kurková, Marie ; Weidlich, Tomáš (referee) ; Kalina, Michal (advisor)
This master‘s thesis studies the different factors that can affect biochar in soil and cause its degradation. These factors include irrigation, root exudates and the action of microorganisms. In the experimental part, the degradation of biochar in the soil environment was studied in two ways, firstly without the action of microorganisms, where the effect of irrigation was simulated by leaching biochar in ultrapure distilled water and model rainwater, and the effect of root exudates was simulated by extracting of biochar in citric acid as a model root exudate of maize sown. The extracted biochar solutions without prior cultivation in soil were characterized by pH, conductivity, UV-VIS analysis and elemental analysis. The biochar residues after extractions were characterized for morphology by SEM, structural differences by FTIR, and organic and mineral content by TGA analysis. The biochar samples after cultivation in soil were subjected to extractions under the same conditions and the same analyses were performed. The effect of cultivation in soil on biochar resulted in a change in elemental composition, a decrease in biochar alkalinity and changes in the ratio of organic matter and mineral fraction were observed. The decrease in pH and conductivity of biochar was mainly related to potassium leaching. The structural and morphological analysis indicated that there is no significant degradation of the structure of the biochar due to washing or cultivation in soil, but there is a partial fouling of the biochar pores by low molecular weight impurities from the soil. These results suggest a short-term action of biochar in soils as a source of nutrients (potassium, phosphorus) and, conversely, a long-term action as a soil conditioner.
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Dissolved Air Flotation – From Pilot Plant to Full Scale Implementation
Dobiáš, Pavel ; Hlaváč, Jaroslav (referee) ; Janda,, Václav (referee) ; Vávrová, Milada (referee) ; Dolejš, Petr (advisor)
The thesis deals with the use of dissolved air flotation (DAF) in water treatment technology in the Czech Republic. It summarizes the knowledge gained at pilot plant studies as well as the experience with full-scale flotation units which have been built in potable water treatment plants in the Czech Republic in years 2006-2018. This thesis provides a broad background of experimental studies of a modern separation process, which does have great advantages in the removal of natural organic matter and microorganisms from water in the drinking water treatment industry. In this thesis, there are presented some examples of the excellent efficiency of the microorganisms removal, both under the experimental conditions as well as water treatment plants, which were improved by DAF units installation in full scale. In addition to the high separation efficiency, it is shown, how DAF units could influence the subsequent separation steps as for example filtration through the granular media. The negative influence of the pre-ozonization on the DAF separation efficiency in Hradec Králové WTP is demonstrated too. The results of the pilot experiments support the idea, that the key condition for high removal efficiency is the optimal coagulation process chemistry. Design of pilot experiments was based on the factorial planning theory and some results are discussed in this thesis. The very big portion of the pilot experiments was made for estimating of the full-scale DAF design parameters before the water treatment plants reconstruction phase
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Use of plasma jet for biomedical application
Doubravová, Anna ; Márová, Ivana (referee) ; Skoumalová, Petra (advisor)
This master´s thesis is focused on the utilization of the sterilization effects of low temperature plasma towards the bacterial microorganisms that occur mainly on the human skin. The plasma sterilization process is fast efficient, non-toxic, environmentally friendly, cost-effective and safe for the operating staff as well as for the patient. Another advantage of using low temperature plasma is to support cell proliferation and wound healing. By combining these advantages, an effective method can be obtained, which would sterilize the wounds sparingly with regard to the surrounding healthy tissue and support the regeneration of the damaged tissue at the same time. In the experimental part, gram positive and gram negative bacteria were used to prove the sterilization effects with respect to different cell wall structure. Staphylococcus epidermidis and Propionibacterium acnes, which cause purulent skin inflammations, were used as gram-positive microorganisms. Serratia marcescens and Escherichia coli were selected from gram positive bacteria. These model organisms were inoculated at various concentrations on culture broths and treated by plasma at a distance of 1 mm from the agar surface. The microwave discharge was generated in argon at a power of 9 W, a gas flow rate of 5 l / min and water cooling to avoid thermal effects on the treated surface. Subsequently, model skin cells of HaCaT were exposed to low temperature plasma and tested for plasma cytotoxicity to demonstrate its healing effects. The obtained results make it possible to state that the sterilizing effects of low-temperature plasma in all tested gram-positive and gram-negative bacterial strains are verified in this work. Finally, tests were demonstrated using a suitable method of the treatment on human skin cells, where the safety and usefulness of the tested low-temperature plasma was demonstrated when applied to shorten the healing process.
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Mikrobiologie čerstvých a polotvrdých sýrů – změny v počtech významných skupin mikroorganismů v průběhu výroby a skladování.
Vítová, Jana
The aim of the thesis was to find out whether the numbers of important groups of microorganisms in fresh and semi-hard cheeses change during storage. Changes in the number of microorganisms were detected by microbiological analysis, where significant groups of microorganisms were determined. The total number of microorganisms, psychrotrophic microorganisms, coliforms including Escherichia coli, lactic acid bacteria and micromycetes including yeasts and molds were detected. The microorganisms were detected in fresh cheeses packed in boxes, vacuum packed stored for 14 days and stored for 21 days. The fresh cheeses were produced in the dairy manufactory of the Faculty of AgriSciences at Mendel University and contained four different concentrations of cream starter. For the semi-hard cheeses microbiological analysis was carried out on delivery of the cheeses to the laboratory and subsequently at an interval of either 14 days or 8 weeks. The semi-hard cheeses were obtained from the market. Very low numbers of coliforms and moulds were detected in packaged fresg cheeses. On the other hand, due to the longer storage time, there was a significant decrease in lactic acid bacteria. Longer storage period resulted in higher detection of yeast and psychrotrophic microorganisms. As for semi-hard cheeses that were analysed after 8 weeks, there was a decrease in the total number of microorganisms and lactic acid bacteria. For semi-hard cheeses analysed after 14 days, higher total numbers of microorganisms, psychrotrophic bacteria and moulds were detected. No coliforms were detected in any of the semi-hard cheeses, including Escherichia coli. The results of the work showed that vacuum packaging of fresh cheeses can extend their shelf life. However, longer storage times reduce lactic acid bacteria.
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Možnosti využití mikroorganismů pro výrobu tuku z odpadních materiálů
Novotný, Jonáš
The aim of the work was to use special strains of microorganisms to produce lipids and lipophilic substances using wastes and by-products of the food industry. Lipids are a valuable component of food and their increasing consumption has an impact on the growth of input costs of plants. Some strains of yeast and bacteria can accumu-late high concentrations of lipids in the cell. The composition of these lipids has a si-milar character to commercially used fats and oils. The work focuses on the production of both equivalents of e.g. cocoa butter or palm oil, and specific products such as polyunsaturated fatty acids, which are used for example to enrich foods. For the cultivation of oleaginous strains of microorganisms, waste and by-products of the food industry are used as a carbon substrate. Individual substrates, which are often subject to disposal in incinerators, are described as potential low-cost media for microbial production technology. Some of the carbon sources discussed include whey, fruit and vegetable pomace and waste cooking oil. Furthermore, the extraction of microbial lipids by chemical and physical methods is addressed. In particular, microbial lipid production appears to be the future of food industry. The technology is still in its infancy and the biggest problem is the cost of the resul-ting products, mainly related to the treatment of substrates and extraction processes. Until costs are significantly reduced, microbial lipids and their products will not be compe-titive.
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Biofilmy v potravinářském průmyslu
Škrobáčková, Monika
The work is focused mainly on bacterial biofilms, which are typical for the food industry. This work describes their history, definition, structure, formation and evolution, which includes their communication or quorum sensing (QS). Furthermore, the microorganisms that can form biofilms are described in detail in this thesis, such as the genera Escherichia, Staphylococcus, Enterococcus and others. The locations where biofilms are most commonly found in food industry such as dairy or meat industry are also described. Their detection and prevention methods are also described, which include individual tips on how to prevent biofilm formation itself. For example, sanitizers, natural antimicrobials, enzymes or nanoparticles are used.
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Heat effects of microbial life in soil
Drápalová, Karolína ; Kalina, Michal (referee) ; Krouská, Jitka (advisor)
This research is intended to be an application of calorimetry to the study of thermal manifestations of microbial life in soil. Although this research has slowly but steadily expanded over the past half century, many unanswered questions still remain. Calorimetry is a suitable tool for determining several parameters of soil quality. Therefore, it is a very important indicator for agriculture. Very well-known indicators used in soil research can be measured by various calorimetric methods such as differential compensation calorimetry (DSC) and thermogravimetry (TG), which are temperature scanning methods used to estimate certain properties of soil material. Calorimetry can be used to determine the activity of microbial life in the soil, which is an essential parameter for the proper functioning of the soil, i.e. for its health. Microorganisms will release a certain amount of heat, based on their metabolism, which can be boosted by adding certain nutrients. We can therefore say that the presence of microorganisms in the soil can be detected thanks to calorimetry.
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Food supporting the intestinal microbiota
JAROLÍMOVÁ, Kristýna
Diet is an important factor that affects the composition and function of the gut microbiota. The aim of this bachelor thesis was to evaluate the possible influence of food representation in the diet on gut microbiota through a questionnaire survey. A total of 753 questionnaires were obtained. It was found that the majority of respondents (89%) believe that microorganisms are important for proper digestion. Women consume more fruit than men (34%, resp. 22%; P <0,01) and are more likely to follow alternative diets such as vegetarianism. Low daily consumption of fried and fast food was found to be favorable (5% of men and no women; P <0,01). The results of this study support the importance of diet as one of the factors influencing the gut microbiota. This issue is important in view of the increasing prevalence of diseases related to gut microbiota balance.
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Možnosti využití mikroorganismů pro rozklad plastového odpadu
HEŘMANOVÁ, Pavlína
Heřmanová, P. Possibilities of using microorganisms for the decomposition of plastic waste.. České Budějovice, 2023. Bachelor Thesis at Faculty of Agriculture and Technology of University of South Bohemian. Thesis Supervisor Kristýna Perná Mgr.Ing. Ph.D. This work deals with possibilities of biodegradation of plastics using microorganisms. The production of the most used plastics and their use is described here, and I also deal with plastic waste and its leakage into the environment. Attention is paid to microorganisms and their enzymes, which are capable of biodegrading plastics, and the met hods used in evaluating the course of biodegradation are further evaluated
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