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PREPARATION AND CHARACTERIZATION OF BIOPOLYMER-BASED NANOPARTICLES AND NANOFIBERS AND THEIR APPLICATION IN FOOD AND COSMETICS
Kundrát, Vojtěch ; Vilčáková, Jarmila (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The presented dissertation thesis deals with the polymer polyhydroxybutyrate and other biopolymers as a basic building block for the construction of micro- and nanoscopic structures and materials used in food and cosmetics. In the theoretical part, current literary review is prepared to introduce the basics of this application field. The practical part of the work is composed of three blocks developed during the doctoral study. In the first and most important part are summarized comments to the academic and patent outputs, where among the academic ones it is possible to find two peer-reviewed articles dealing with the electrostatic and wet spinning of PHB and properties of prepared materials. The patent outputs consist of several accepted and applied projects, which summarize results on both PHB spinning methods, but also on general approaches enabling the processing of PHB into forms enabling many applications in food and cosmetics. Second part was focused on the patented composition of the UV protection cream based on the prepared nanoscopic and micro- morphologies of PHB. The third block summarizes results focused predominantly on the electrostatic spinning of PHB and other biopolymers. Finally, a short chapter containing a brief description of projects that were in a way related to the dissertation topic, but rather practical development work in Central Tanzania and West Africa, which draw on knowledge and contacts gained during studies at FCH BUT Brno.
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Study of biodegradation of poly(hydroxy alkanoates).
Wurstová, Agáta ; Přikryl, Radek (referee) ; Obruča, Stanislav (advisor)
The master‘s thesis is focused on the study of biodegradation of polyhydroxyalkanoates, namely polymer polyhydroxybutyrate. The first part of the thesis is focused on the study of biodegradation of polyhydroxybutyrate in the form of crystalline granules of PHB and PHB films using selected species of microorganisms from bacteria, yeasts and fungi. As a representative of bacteria was chosen microorganism Delftia acidorovans, as yeast was selected Aureobasidium pullulans and Aspergillus fumigatus as fungi. PHB depolymerase activity was measured employing turbidemtiric method with suspension of PHB granules as substrate. The results showed that D. acidorovans can partially degrade PHB. On the contrary A. pullulans cannot effectively degrade PHB. The most significant degradation ability revealed A. fumigatus, which was able to degrade PHB completely. Extracellular enzymes excreted by these microorganisms when cultivated on PHB materials as sole carbon sources were analyzed by SDS-PAGE. The second part of the thesis deals with the biodegradation of PHB in the form of PHB film, PHB hardened foil and PHB Nanoul fabric using standard composting test. Semi-solid cultivation showed positive results. In the interval from 14 days to two months were all forms of the PHB completely biodegraded. With semi-solid cultivation was also studied biodegradation rate of the polyurethane elastomeric films which were modified by partial replacement of polyester polyol by PHB. The test samples were prepared using PHB from Sigma and the PHB samples prepared at the Faculty of chemistry VUT. Samples with different concentrations of the dispersed PHB (1 %, 5 % and 10 %) in the polyurethane were also object of the study. At the end of the cultivation (after 2 months) were measured mechanical properties in tension of the material, then efficiency of biodegradation by gravimetric analysis and modification of the material surface by microscopic analysis.
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FTIR analysis of soils containing plastics and microplastics
Sinčáková, Lenka ; Pavlovský, Jiří (referee) ; Doležalová Weissmannová, Helena (advisor)
This bachelor thesis deals with the sources of microplastics in soils, their potential toxicity for men as well as the environment and soil-plastic interaction. It provides an overview of methods that are commonly used for qualitative and quantitative characterisation of microplastics in soils with focus on FTIR spectrometry. In the experimental part, real soil samples were evaluated with the use of ATR-FTIR based on model soils-microplastics mixtures calibrations. Vaidation models for model mixtures and carbon content were also evaluated.
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Configuration of QoS in IP network using Cisco devices
Brož, Kamil ; Šporik, Jan (referee) ; Růčka, Lukáš (advisor)
This bachelor's thesis is divided into two main sections. The first, theoretical section, deals with parameters and requirements of modern real-time applications. This project analyses the particular means of providing QoS. It deals with access in a form of integrated services (IntServ) and with newer access in a form of differentiated services (DiffServ). The chapter covering the Integrated services describes the very basic principles of the problematics. Differentiated services and used algorithms are discussed in detail. The second, practical section, describes the capabilities of Cisco devices and their particular implementation in two designed network scenarios including traffic measurement and user experience tests.
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Utilization of spent wood chips for biotechnological production of PHA
Ladický, Peter ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
The aim of this work was to study the suitability of wood shavings and sawdust as a substrate for microbial production of PHA by bacteria Burkholderia cepacia and Burkholderia sacchari. In the experimental part of the work the most appropriate approach of hydrolysis of wood shaving and sawdust and the effect of polyphenol and furfural concentration on ability to accumulate PHA was studied. Burkholderia sacchari had greater ability to accumulate PHA compared to Burkholderia cepacia. PHB values 87–89 % were achieved when Bulkholderia sacchari was cultivated on medium that contained detoxified hydrolysate of sawdust. Sawdust is therefore a promising substrate for microbial production of PHA in terms of reducing production costs and high content of PHB in biomass.
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Biodegradable seed carriers for large area regeneration of forests
Balej, Marek ; Kučera, František (referee) ; Jančář, Josef (advisor)
This diploma thesis is focused on finding a suitable biodegradable polymer for the construction of mechanically activated forest seed carriers. The subject of the theoretical part of the work is a description of the investigated polymeric materials and characterization of the species composition of trees in domestic forests. Furthermore, the issue of technology to produce these seed carriers for the preparation of prototypes using 3D printing and for high-volume production through plastic injection moulding is elaborated. Finally, in this section, attention is paid to the difference between biodegradable and compostable plastics. The experimental part of the thesis deals with the application of the method of determining the complete aerobic biodegradability of the investigated materials in the soil, measuring the amount of carbon dioxide released and additional DSC, GPC and TGA analysis. It further investigates the saturation of the samples with carbon dioxide, their subsequent temperature-induced batch foaming and SEM analysis of the resulting structure. Finally, it focuses on the preparation of 3D printed prototypes of seed carriers and test specimens, on which the tests of their impact strength and tensile properties are performed. For more detailed analysis, two commercially available bioplastics, NonOilen® and ecoflex® were selected. The test of complete aerobic biodegradability of plastics in soil according to ISO 17556 proved that the biodegradation of NonOilen® and ecoflex® in the soil took place. This was subsequently substantiated by the results of the associated DSC, GPC and TGA analysis. Furthermore, in pressed samples from both materials, it was found by SEM observation that the method of CO2 saturation and subsequent batch, temperature-induced foaming is ineffective in obtaining a porous structure in the given materials. Finally, the impact strength and tensile properties of 3D printed prototypes for the investigated materials (NonOilen® and ecoflex®) were determined using 3D printed test specimens.
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Extraction of Poly(3-hydroxybutyrate) from Biomas
Jašek, Vojtěch ; Ing. Jiří Švrček, Ph.D (referee) ; Figalla, Silvestr (advisor)
Polyhydroxyalkanoates are a group of biopolymers which occur in cells of microorganisms. These biopolymers can be considered as alternatives to commonly used petrochemical materials such as polypropylene and polyethylene due to their physical and chemical properties. This bachelor thesis focuses on isolation of particular kind of PHA from biomass and contains both experimental and theoretical part. It consists of information about the origin and usage of PHA, challenges and problems of their biotechnological production and mainly various ways of downstream. Experimental part includes comparison of PHA extraction from biomass done by two ester solvents. Studied parameters were molecular weight of the polymer, solvent extraction ability and their resistance against hydrolysis. The main goal of this thesis was to verify the best process conditions of isolation done by nonhalogenated bio-solvent.
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Controlled production of polyhydroxyalcanoates by bacterial strain Ralstonia eutropha using different substrates
Šnajdar, Ondřej ; Duroňová, Kateřina (referee) ; Márová, Ivana (advisor)
This bachelor’s thesis deals with production of polyhydroxyalkanoates (PHA) by bacterial strain Ralstonia eutropha. Production of PHA on different substrates has been studied to lower the costs of feedstock. In theoretical part the review has been done about the most important types of PHA, production strains and possibilities of cultivation of Ralstonia eutropha using different substrates. In practical part there has been studied production of PHA on different vegetable oils, including waste oils from different sources (restaurants, homes, food companies). Incorporation of different precursors for copolymer production control was studied too. The highest yields of poly-3-hydroxybutyrate (P3HB) have been achieved using waste oils. For economical and ecological reasons these oils are very suitable substrates. Using concentration 20 g/l of waste rapeseed oil from university canteen there has been produced 13,32 g/l of biomass containing 58,63% of P3HB in 84th hour of cultivation. The highest yield of PHA in precursors study has been achieved applying 1% propanol in 24th hour of cultivation. The PHA increase has been 97%. This PHA was composed from 91% of 3HB and 9% of 3-hydroxyvalerate.
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Biotechnological production of polyhydroxyalkanoates using wastes of coffee production
Vašíčková, Monika ; Benešová, Pavla (referee) ; Obruča, Stanislav (advisor)
This bachelor thesis is focused on study of production of polyhydroxyalkanoates (PHA) by bacteria Burkholderia cepacia and Burkholderia sacchari. Production of PHA has been studied using spent coffee grounds hydrolysates which have been prepared by different aproaches. In the thesis is compared standard method of coffee ground hydrolysis by mineral acid followed by enzymatic hydrolysis. Hydrolysates which have been produced were analyzed in terms of concentration of saccharides and efficiency of hydrolysis. The best producer of PHA (based on results) was bacterium Burkholderia cepacia, in the medium which has been prepared by hydrolysis of spent coffee grounds extracted by 60% solution of ethanol. Biomass yield of this cultivation was 3,553 g/l with 32,472% PHA content. This PHA contained 6,09% 3-hydroxyvalerate. In the other experiment, we verified alternative hydrolysis of spent coffee grounds – by commercially available enzymes. We used cellulase, hemicellulase and the enzymatic cocktail which has been produced by mould. Hemicellulase was the most effective hydrolytic enzyme and its application resulted in production of the highest amount of biomass – 5,708 g/l. In this cultivation, only homopolymer PHB has been which is probably caused by the fact, that during the enzymatic hydrolysis levulinic acid or any other potential precursor of 3HV is formed.
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Influence of selected parameters on biotechnological production of polyhydroxyalkanoates
Eremka, Libor ; Pekař, Miloslav (referee) ; Obruča, Stanislav (advisor)
The aim of this work is to study microbial production of polyhydroxyalkanoates (PHA). Theoretical part is focused on production of PHA using microoganisms and transgenic plants. Bacterial strain Cupriavidus necator H16 was used for laboratory production of PHA. Various waste oils were used as sole carbon and energy source. Salt of propionic adic and 1-propanol were used as intermediate for 3-hydroxyvalerate monomer (3HV) unit. Incorporation of 3HV to polymer can improve material features of PHA. The major part of experimental work was focused to study influence of aeration (concentration of dissolved oxygen) to bacterial growth, selected metabolic pathways and formation of PHA. Furthermore, influence of aeration to monomer composition of polymer was evaluated. According to experimental conclusion of this work it was approved dependance between aeration and monomer composition of PHA. Moreover, it was approved that higher concentration of oxygen supports bacterial growth and influences PHA content in cells. In addition, NADPH is one of the substrates influencing flux of acetyl-CoA throughout the metabolism; higher intracellular concentration of NADPH inhibits TCA cycle and enhances accumulation of PHA in cells. For this reason, specific enzymatic aktivity of several selected intracelular enzymes were measured, including those enzymes which can generate NADPH.
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