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Thermal analysis of fuels
Šrámek, Zbyněk ; Hrnčířová, Michaela (referee) ; Moskalík, Jiří (advisor)
The main goal of this thesis is to introduce the field of thermal analysis as an independent scientific discipline. The first section is mostly informative and introduces into a concept of thermal analysis. The second part describes the most fundamental and essential methods of thermal analysis and the last section is focused on evaluating a real thermogravimetric experiment which deals with biomass sample.
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Utilization of biomass for the energy purposes
Romanová, Kristýna ; Ing.Ondřej Kosík, Ph.D. (referee) ; Flodrová, Dana (advisor)
The theoretical part of work focuses on the issue of biomass used for energy purposes, in particular agricultural waste, which can be used as a substrate for biogas station. Furthermore, examines the composition of polymer substrates, which affects most biogas process. The aim of this work was to measure each sample of enzyme activity of biomass, which is used as a raw material for biogas plants.
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Solubility analysis of lignocellulosic substances with antioxidative efficiency
Hrušková, Lucie ; Kalina, Michal (referee) ; Kovalčík, Adriána (advisor)
One of the main obstacles to efficiently valorise lignin is its heterogeneous solubility, which varies depending on the biological origin and the method of isolation. The theoretical part of the bachelor thesis is devoted to a basic description of lignin from its structure to its specific properties, which has led to a wide range of studies on lignin. The experimental part of the thesis deals with the determination of the solubility of commercially available lignin in selected organic solvents Solubility was determined in a total of 15 pure or mixed solvents. The highest solubility of lignin was achieved in water, in which a solubility of 99.16 % was measured. For the eight best solvents, the size and stability of the dissolved particles were further analyzed. It was found that nanoparticles can be prepared using water and DMSO. Further, the antioxidant activity (expressed by TEAC parameter) and its structure (by FTIR) were determined for the dissolved lignin and its change was recorded. Based on the solubility results, two and three step fractionations were performed. Size, stability, and antioxidant activity were determined for the final fractions. The results obtained showed that during each fractionation step, characteristic functional groups were removed, thus decreasing the antioxidant activity of the resulting fractions.
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Isolation of lignin from grape seeds and its application as filler for polyhydroxyalkanoates (PHA)
Vostrejš, Pavel ; Vítová, Eva (referee) ; Kovalčík, Adriána (advisor)
This diploma thesis deals with 1) the preparation of biodegradable polymer films based on polyhydroxyalkanoates (PHA) and 2) their modification by lignin as an active additive. The motivation for this work was to prepare active packaging material for food packaging. Polymer films were prepared by blending of neat crystalline poly(3hydroxybutyrate) (P3HB) and amorphous polyhydroxyalkanoate (PHA). The lignin was isolated from grape seeds derived from grape pomace. The solubility of lignin in chloroform was improved by acetylation. The properties of the isolated lignin were determined by elemental analysis, ash content, and infrared spectroscopy (FTIR). Lignin was used as an active additive for the modification of polymeric films prepared by solution casting of P3HB or P3HB blended with amorphous polyhydroxyalkanoate. The effect of different concentrations of lignin in the range of 1 to 10 % was tested. The lignin type and concentration had a different influence on the final thermal and mechanical behaviour of polymeric films. Lignin increased the values of the Young modulus and tensile strength of the prepared films. Differential scanning calorimetry data confirmed that lignin positively modified crystallization kinetics of P3HB. Thermogravimetry was used to analyse the thermal stability of PHA films. Lignin markedly increased the thermal stability of PHA films. However, acetylated lignin harms the mechanical properties of films. Moreover, this work showed that lignin isolated from grape seeds and added into PHA films proved its high antioxidant capacity. PHA films with lignin displayed much better gas barrier properties compared with PHA films without lignin. The prepared bioactive PHA films fulfil the requirements for sustainable food packaging with high antioxidant capacity and excellent gas barrier properties.
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Vliv ligninu ve funkci plniva na pevnost lepených spojů materiálů na bázi dřeva
Klonová, Sára
Analysis of the effect of lignin added in various amount to binders containing thermoreactive resins commonly used for bonding wood-based materials is a main theme of this thesis. Itʼs also related to a similar problem analysed in the bachelor thesis – influence of added lignin into heat-activated adhesives, so it can complete already obtained results with some new findings by a change of analysed wood-based material. Practical part of this thesis is focused on a strength of adhesive joints bonded with binders that contain different amount of lignin. Adhesives are applied on a surface of testing samples made of ash and larch and then climatized in a various moisture condition. The tensile strength, shear tensile strength and flexural strength of adhesive joints are being tested. Thesis provides application of obtained results of utilisation of lignin as filler of adhesives used for bonding wood-based materials exposed to specific physical – mechanical factors in practice.
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Targeted editing of the Arabidopsis CYP98A3 gene using the CRISPR/Cas9 method
Šamaj, Matej
Lignin is an abundant biopolymer, which fulfils several important functions including facilitation of polar water transport and mechanical strengthening of plant body. It is required for proper growth and development of plants but also for plant defence responses. Complex lignin biosynthesis involves the activity of numerous enzymes catalysing diverse chemical reactions that are stepwise generating various precursors for lignin formation. One such enzyme of lignin biosynthetic pathway, P‐COUMAROYL SHIKIMATE 3′‐HYDROXYLASE (C3′H), is encoded by the gene CYP98A3/ C3′H and convert p-coumaroyl shikimate to caffeoyl shikimate. CRISPR/Cas systems adapted from prokaryotes, where they provide adaptive immunity, have very quickly evolved to unique and powerful tool for precise gene editing. The CRISPR/Cas9 technology allows to specifically target desired sites within the genomes to subsequently perform very precise mutagenesis of selected gene(s). The purpose of this thesis was to employ the CRISPR/Cas9 method to perform targeted editing of the CYP98A3/C3′H gene in transformed Arabidopsis thaliana plants. Selected transformed plants were verified to confirm the presence of CRISPR/Cas9-mediated gene editing. The verified T2 generation putative mutant plant shows altered phenotypes of leaves, leaf rosettes, stems and inflorescences accompanied by lower deposition of lignin as revealed by histochemical staining by basic fuchsin and microscopic observations.
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Production of lignin-degrading enzymes by Phanerochaete chrysosporium
Péčiová, Bianka ; Hudečková, Helena (referee) ; Kovalčík, Adriána (advisor)
This diploma thesis deals with the study of the production of ligninolytic enzymes produced by the mold P. chrysosporium and subsequently their immobilization. The theoretical part describes the selected production microorganism, principles of action of ligninolytic enzymes (lignin-peroxidase, manganese-dependent peroxidase and laccase) and methods of their immobilization. In the experimental part, optimal conditions of the production of ligninolytic enzymes by P. chrysosporium were monitored as a composition of culture medium with different glucose content and with using two different inducers: lignin and guaiacol. During the 14-day cultivation cycles, the enzyme activity of lignin-peroxidase, manganese-dependent peroxidase and laccase was monitored on each day of cultivation. Based on the optimized enzyme production procedure, the enzymes were subsequently immobilized by various methods: by method of forming enzyme aggregates (CLEA), adsorption on bacterial cellulose (BC) and a combination of both (CLEA + BC). The CLEA method proved to be the most effective, but there was problem with isolation of enzyme aggregates. Therefore, immobilization on bacterial cellulose associated with the enzymes aggregates was chosen as the most advantageous. With this method, the operational stability of the immobilized enzymes was monitored in 7 consecutive reaction cycles. Subsequently, CLEA and CLEA with BC were used to modify the model phenolic substance, where the alkali lignin was selected. For both sets of immobilizers was confirmed the effect of the enzymes on the lignin structure by measuring the molecular weight (Mw) and polydispersity index (PI).
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Study of the effect of microbial degradation of lignin on its molecular weight
Fialová, Tereza ; Hudečková, Helena (referee) ; Kovalčík, Adriána (advisor)
This diploma thesis deals with the microbial degradation of lignin using wood-degrading fungi Fomitopsis pinicola and Lenzites betulina. In the first phase of the experimental part, media screening was carried out, the aim of which was to select the best media for fungal growth and production of ligninolytic enzymes. Based on the determination of activity, in the next step, the conditions for their production were optimized in selected media. As part of these experiments, the optimal concentration of lignin and glucose was selected for subsequent cultivations. Commercially available lignin was used as substrate. Based on the results of measured enzyme activities, Lenzites betulina was selected as the better producer. The most produced enzyme of this fungus was laccase, followed by manganese-dependent peroxidase and the least lignin peroxidase. Further experiments were performed only with L. betulina. In the next part of the experiment, lignin was characterized, and its properties compared before and after microbial degradation. Its molecular weight was determined by SEC-MALS and the change in structure by FTIR. The molecular weight of lignin decreased after cultivation and a change in its structure was also noted. The results show that the microbial degradation of lignin was successful.
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