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Use of microcalorimetry in the study of hydration of biopolymers
Bola, Tomáš ; Smilek, Jiří (referee) ; Krouská, Jitka (advisor)
This master thesis deals with the using of microcalorimetry in the study of hydration of biopolymers. Lactose has been selected together with the other biopolymers although it is not among biopolymers but disaccharides. Selected biopolymers are alginate, dextrane, chitosan and hyaluronan of two molecular weights. Lactose has been selected for these purposes mainly because it is a model example to determine whether or not the reaction to moisture between the other samples and the saturated salt solution occurs. The biopolymer hydration study, as opposed to the commonly used perfusion calorimetry method using the possibility of measuring with adjustable moisture has been used an isothermal microcalorimetry method where at two constant temperatures the reaction of the sample to the different moisture released by the saturated salt solution was monitored.
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Usage of physical-chemical methods for the study of interaction of humic substances with the plant cutisles
Rampáčková, Eliška ; Sedláček, Petr (referee) ; Smilková, Marcela (advisor)
This bachelor’s thesis deals with the study of interaction (or binding or adsorption) of plant cuticle with potassium lignohumate, as a liquid agriculture product used in the field of foliar fertilization, which belongs to the most used agronomic applications in general. The studied materials became the plant cuticle, which forms upper part of plants and potassium lignohumate (commercially Lignohumate), which is widely used thanks to its properties, which allow to increase the quality, growth and profitability of the crops. The aim of this bachelor’s thesis was to investigate the binding of compounds to plant cuticles, useful methods for this field of research and the use of thermal methods (precisely isothermal microcalorimetry and thermogravimetry). The next step was to use this instrumentation as a physicochemical method for assessing the ability of Lignohumate to bind to plant cuticles.
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Use of microcalorimetric techniques in the study of stress adaptation of microorganisms
Korfantová, Stanislava ; Slaninová, Eva (referee) ; Krouská, Jitka (advisor)
This bachelor thesis uses microcalorimetric techniques to study stress adaptation of wild strain of H. halophila and H. halophila strain adapted to lower salinity of medium in the environment of levulinic acid, which occurs naturally in hydrolysates of lignocellulosic materials. These can serve as inexpensive substrates on which H. halophila is capable of producing polyhydroxybutyrate. Microcalorimetric measurements showed that the wild-type H. halophila strain could adapt to levulinic acid to a concentration of 5 g/l. The adapted strain, which was assumed to have poorer stress management based on lower PHB yields, could adapt to all observed concentrations. The results were compared with a conventional method that confirmed the results of microcalorimetry. Microcalorimetry has been evaluated as a universal and susceptible method that is suitable for studying the metabolic activity of microorganisms. To better interpret the obtained microcalorimetric results, it is necessary to supplement the technique with information from other analytical techniques. The bachelor thesis uses spectrophotometric and gravimetric determination and gas chromatography with a flame ionization detector to characterize the wild and adapted strain before monitoring the adaptation to levulinic acid. The techniques offered enriching information to supplement the microcalorimetry outputs.
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Behaviour of microorganisms using microcalorimetry
Piletskaya, Maryia ; Sedláček, Petr (referee) ; Krouská, Jitka (advisor)
The diploma thesis deals with the study of the behavior of a microorganism with the help of microcalorimetry. The theoretical part of the thesis deals mainly with the characterization of the microorganism Rhodospirillum rubrum selected for experimental work and the application of microcalorimetry in microbiology. The second goal was to screen the growth of the bacterial strain R. rubrum using different substrates, and subsequently, based on experimental results, to select the most suitable substrate, and optimize its concentration and aeration of the medium for the microorganism using microcalorimetry. Hexanoate, malate, acetate and fructose were used to examine the most suitable substrate by microcalorimetry. Another goal was data processing and discussion of the advantages and disadvantages of substrate selection and media aeration with respect to bacterial strain growth. Hexanoate was found to be the best substrate for growth, followed by optimization of the concentration and aeration of the medium. The results of the microcalorimetric measurement were confirmed by spectrophotometric study of the growth curve of the investigated bacteria. The effect of osmotic pressure on bacteria and the dependence of their survival on the amount of polyhydroxyalkanoates (PHA) in the cell were also studied. The amount of PHA in the biomass was determined chromatographically.
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Biocompatible Amphiphilic Compounds and their Interactions with Polymers
Burdíková, Jana ; Sedlařík, Vladimír (referee) ; Bakoš, Dušan (referee) ; Pekař, Miloslav (advisor)
This work is focused on the study of interaction between hyaluronan and high-biocompatible amphiphilic molecules. Using fluorescent probe method, screening of the interaction of cationic lipid 1,2-dipalmitoyl-3-trimethylammonium-propane (DPTAP), mixture of this cationic lipid with zwitterionic lipid, 1,2-dipalmitoyl-sn-glycero-3-phosphochloline (DPPC), with hyaluronan, both native and hydrophobically modified was carried out. Results showed the self-aggregation of DPPC and DPTAP independently on lipids ratio in the mixture and the interaction of DPTAP and DPPC/DPTAP aggregates with hyaluronan at specific ratio of DPTAP and hyaluronan concentration. Physical properties of formed membranes and the influence of cholesterol were also investigated at different DPPC and DPTAP concentration ratio. Last but not least, the non-ionic surfactant-DPPC systems were studied, namely, the size of the formed aggregates, the thermodynamics of solubilisation and the interaction with native hyaluronan.
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Utilization of thermal analysis in the study on effects of microbial inhibitors
Bošeľová, Miriam ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the use of thermal analysis in the study on effects of microbial inhibitors. The main aim of this work was to determine the utilization of the method, which is mainly used in different fields of science and research. Three bacterial strains: Cupriavidus necator H16, its mutant strain Cupriavidus necator PHB-4 and Halomonas halophila, were used as model microorganisms. The inhibitory effect of levulinic acid on growth and metabolic activity was monitored by microcalorimetry. It was found that bacteria were able to adapt to levulinic acid to a certain concentration - Cupriavidus necator to 5 g/l and Halomonas halophila to 2 g/l. The thermal analysis results were compared to a conventional method, which is commonly used to study the growth of microorganisms.
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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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Characterization of Mechanical Properties of semi-IPN Hydrogels Based on Poly(vinylalcohol)
Přibyl, Jiří ; Pekař, Miloslav (referee) ; Kalina, Michal (advisor)
This diploma thesis deals with the issue of mechanical properties of semi-IPN hydrogels based on poly(vinylacohol). The prepared poly(vinylalcohol) hydrogels were modified by the addition of sodium alginate, dextran, DEAE-dextran, chitosan, and poly(ethyleneglycol). The mechanical properties were studied by various methods, such as the oscillatory amplitude rheological test, dynamic mechanical analysis, swelling experiments and drying characteristics. Microcalorimetry was used to study the interactions between poly(vinylalcohol) and biopolymers in solution using the ITC method and the morphology of prepared hydrogels was visualized using cryo-SEM. The main concept for semi-IPN hydrogels is that there is minimal influence on the mechanical properties but leads to the modification of the binding sites present in the hydrogel structure, which has a high potential in transport properties. From the experimental results, the effects of each biopolymer on the mechanical properties were determined. The obtained results showed that the additions of biopolymers do not have a significant impact on the mechanical properties of PVAl hydrogels, but in the case of swelling experiments, there is a significant influence of the number of freezing/thawing cycles, ionic strength of the environment, and the used biopolymer.
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Use of microcalorimetric techniques in the study of stress adaptation of microorganisms
Korfantová, Stanislava ; Slaninová, Eva (referee) ; Krouská, Jitka (advisor)
This bachelor thesis uses microcalorimetric techniques to study stress adaptation of wild strain of H. halophila and H. halophila strain adapted to lower salinity of medium in the environment of levulinic acid, which occurs naturally in hydrolysates of lignocellulosic materials. These can serve as inexpensive substrates on which H. halophila is capable of producing polyhydroxybutyrate. Microcalorimetric measurements showed that the wild-type H. halophila strain could adapt to levulinic acid to a concentration of 5 g/l. The adapted strain, which was assumed to have poorer stress management based on lower PHB yields, could adapt to all observed concentrations. The results were compared with a conventional method that confirmed the results of microcalorimetry. Microcalorimetry has been evaluated as a universal and susceptible method that is suitable for studying the metabolic activity of microorganisms. To better interpret the obtained microcalorimetric results, it is necessary to supplement the technique with information from other analytical techniques. The bachelor thesis uses spectrophotometric and gravimetric determination and gas chromatography with a flame ionization detector to characterize the wild and adapted strain before monitoring the adaptation to levulinic acid. The techniques offered enriching information to supplement the microcalorimetry outputs.
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Behaviour of microorganisms using microcalorimetry
Piletskaya, Maryia ; Sedláček, Petr (referee) ; Krouská, Jitka (advisor)
The diploma thesis deals with the study of the behavior of a microorganism with the help of microcalorimetry. The theoretical part of the thesis deals mainly with the characterization of the microorganism Rhodospirillum rubrum selected for experimental work and the application of microcalorimetry in microbiology. The second goal was to screen the growth of the bacterial strain R. rubrum using different substrates, and subsequently, based on experimental results, to select the most suitable substrate, and optimize its concentration and aeration of the medium for the microorganism using microcalorimetry. Hexanoate, malate, acetate and fructose were used to examine the most suitable substrate by microcalorimetry. Another goal was data processing and discussion of the advantages and disadvantages of substrate selection and media aeration with respect to bacterial strain growth. Hexanoate was found to be the best substrate for growth, followed by optimization of the concentration and aeration of the medium. The results of the microcalorimetric measurement were confirmed by spectrophotometric study of the growth curve of the investigated bacteria. The effect of osmotic pressure on bacteria and the dependence of their survival on the amount of polyhydroxyalkanoates (PHA) in the cell were also studied. The amount of PHA in the biomass was determined chromatographically.
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