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Biotechnological production of sophorolipids
Šimšová, Veronika ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with the microbial production of sophorolipids by the Starmerella genus yeasts. The theoretical part of the thesis includes general characteristics of biosurfactants with the focus on sophorolipids. There are described the options of biotechnological production of sophorolipids and fields of their possible applications. Furthermore, the theoretical part deals with the describtion of Starmerella bombicola yeast, which is often used for biotechnological production of sophorolipids. Six strains of the Starmerella genus were cultured in the basic medium suitable for sophorolipid produsction. The amount of produced sophorolipids was tested by the emulsification capacity assay, solubilization of crystalline anthracene assay, measuring the surface tension by the Du-Noüy-Ring method and determination of the sophorolipid concentration by extraction with ethyl acetate. The purity of the extracted sophorolipids was inspected by the Fourier Transform infrared spectrosopy (FT-IR) Based on the results, the Starmerella bombicola CBS 6009 and the Starmerella anomalae CBS 14178 strains were studied in greater detail. They were cultured in several production media of different composition and the effect of the individual components on the ability of the sophorolipid production was monitored. Based on the results, it was evaluated that the composition of the medium has a great influence on the production ability of the strains. The highest production rate of sophorolipids was achieved in the basic production medium and so was in the medium containing molasses and Indian waste oil. The cultivation mode has great effect on the sophotolipid production rate. It has been found that when cultured in a bioreactor, the strains produced sophorolipids in a larger amount and of a different quality than in the shaker flasks.
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Microrheology in systems of polymeric colloids
Bjalončíková, Petra ; Sedláček, Petr (referee) ; Venerová, Tereza (advisor)
My bachelor’s thesis was aimed to deal with evaluation of microrheology method in the research of polymer colloids. Used polymers were poly(sodium 4-styrenesulfonate) and sodium carboxymethyl celullose. For measuring of microrheology were used particles with different radius (1 m and 4 m). The results obtained with passive microrheology were compared with results obtained with clasical rheology. It was found, that both substances have viscous charakter. The values of polymer viscosity were similar for dilute solutions in both methods, but for concentrated solutions deviations were found. The reason are polymer nets, which do not allow sufficient movement of particles in concentrated solutions.
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Dry gel forms - aerogels, xerogels - preparation, properties and potential use.
Sedlář, Marian ; Smilek, Jiří (referee) ; Sedláček, Petr (advisor)
The content of this bachelor thesis was to find out what influence has the drying of hydrogel on its internal structure on an appropriate model hydrogel system. In the theoretical part of this thesis selected methods of structural analysis that are commonly used for characterization on gels in their original hydrated state and in dry state were described. In the practical part, agarose based hydrogels with different concentrations and with various additions of polyelectrolytes were chosen as the model hydrogel system. Cryo-scanning electron microscopy and turbidimetry were used for the structural analysis of hydrogels. For the dry gels, scanning microscopy and mercury porosimetry were used. The obtained data and results for our model system can be use in analyse of other hydrogel systems and their dry forms.
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Application of thermal analysis in physiological characterization of microorganisms
Kočiová, Silvia ; Obruča, Stanislav (referee) ; Sedláček, Petr (advisor)
This diploma thesis deals with the applicability of thermal analysis in the influence of stress factors on microorganisms. The main aim of the presented work was to design and implement a series of experiments to thest the usability of advanced methods of thermal analysis in the characterization of microorganisms. Two bacterial strains were used as model organisms: Cupriavidus necator H16 and its mutant strain Cupriavidus necator PHB-4, which differs in the ability to produce polyhydroxyalkanoates. The basic technique used thermogravimetric analysis (TGA), which was optimized and applied in the study of water transport, behavior and determination of intracellular water content with respect to the influence of the presence of intracellular PHB granules. The results of this method were subsequently supported by TEM photos.
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Experimental and computer modeling diffusion of low-molecular solutes in gel – based carriers
Masár, Lukáš ; Gregorová, Eva (referee) ; Sedláček, Petr (advisor)
This diploma thesis is focused on combination of experimental study and computer modelling of diffusion processes in gel phases. The aim of experimental part of the diploma thesis was to test and optimize the setting of the diffusion coefficient in gel medium by using the method of horizontal diffusion cells, commonly used for study of diffusion processes through membranes. Specific description of experiments was to determinate the impact of presence of reactive component in inert hydro-gel carrier on final value of diffusion coefficient of low-molecular model diffusion probe. The defined dependencies were subsequently combined with computer simulation of diffusion process in a properly designed model in order to determinate the experimentally unavailable system parameters. The stated combination of both approaches was proved to be an appropriate instrument for studying of hydro-gels with a wide potential especially in the field of preparation of hydro-gel carriers with controlled release of active substances.
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Adhesion Properties of Semi-IPN Hydrogels
Candráková, Simona ; Sedláček, Petr (referee) ; Kalina, Michal (advisor)
This Diploma thesis deals with optimization of the hydrogel preparation with various additions of substances affecting adhesion, studying the adhesion of prepared hydrogel systems and modifying their adhesion properties. Prepared hydrogels were agarose, alginate and gellan polymer systems with additions of acrylic acid, acrylamide, calcium chloride and Tween 20. The experimental part of the diploma thesis focuses first on optimizing the preparation of individual hydrogels, from which, according to certain criteria, suitable representatives were selected to study adhesion and its controlled modification. Agarose and gellan hydrogels were selected as suitable representatives, which were then used in rheological measurements. Based on these measurements, the effect of the adhesive force and the adhesive work of individual materials was evaluated. It was found that the best adhesion properties of the materials used are unadjusted hydrogels, in the case of hydrogels with the addition of another substance, a negative effect on adhesion was observed, when the adhesion force was reduced and also the adhesion work was reduced.
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Reactivity of modified humic gels
Lang, David ; Sedláček, Petr (referee) ; Klučáková, Martina (advisor)
This bachelor thesis deals with humic acid gels and their ability to bind metallic ions on their surface. In the thesis the adsorption of copper ions on humic gels was studied. The gels were prepared by dissolving the humic acid in sodium hydroxide or sodium tripolyphosphate and then by precipitating with hydrochloric acid or magnesium chloride. Adsorption was studied at different concentrations of the copper (II) chloride and measured on UV-VIS spectrophotometer. It was proved from measuring that gels made from sodium tripolyphosphate are adsorbing less copper ions than the ones prepared by sodium hydroxide. Also, the copper ions are bound with smaller force on gels prepared with polyphosphate. Gels precipitated with magnesium chloride adsorb much more than gels precipitated with acid, Thus the extracted amounts are bigger.
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Preparation of hydrosorbents from humic acids
Nováčková, Táňa ; Giláni, Vladimír (referee) ; Sedláček, Petr (advisor)
This diploma thesis is focused on development and characterization of synthetic hydrogel materials containing humic acids. Based on the literature review, procedure for the preparation of synthetic superabsorbent containing humic acids was designed and optimized in order to maintain required functionality of the resulting materials, such as swelling abilities and to the controlled the release of humic substances. Very important part of this work was also characterization of superabsorbents by wide range of routine physic-chemical methods (rheometry, moisture analyzers, FT-IR). Preparation of these materials is aimed to their use in agriculture and in the environment.
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Fixation media for fluorescence microscopy of liposomes
Kvasnicová, Klára ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with the synthesis of fixation medias suitable for fluorescence microscopy of liposomes. The theoretical part contains a literature search focused primarily on the characterization, classification and use of chemical fixatives in chemical practice. Experimental section also deals with the selection of appropriate fixative for preparation of microscopic preparations based on liposomes.
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Determination of Paracetamol content in selected drugs using ATR-FTIR spectrometry
Waczulíková, Kristína ; Sedláček, Petr (referee) ; Enev, Vojtěch (advisor)
This bachelor thesis deals with determination of paracetamol content in selected drugs by ATR-FTIR spectrometry and aims to design and optimize determination of paracetamol in dosage forms by a direct measurement of the sample, called ‘dry way’. Tablets of three drugs containing paracetamol have been studied. Wavelength ranges were determined from the measured FTIR spectra as regions where the absorptions of fillers (microcrystal cellulose, starch and magnesium stearate) were minimal. Absorption bands of paracetamol were selected at the wavenumbers of 1 503 cm-1 and 1 224 cm-1 in order to construct a calibration curve. The contents of paracetamol in the drug tablets were calculated using calibration curves obtained by the method of simple regression analysis. The lowest deviation from the amount of 500 mg paracetamol per tablet as reported by the manufacturer was from the calibration curve for paracetamol with microcrystalline cellulose. The determined amounts of paracetamol per tablet in the selected drugs lied within range 493.5–505.5 mg. These results point to the conclusion that the ATR-FTIR spectrometry method can be used for the quantitative determination of paracetamol in drugs using direct measurement, as deviations from the reference value of 500 mg did not exceed 1.5 % for cellulose and 3.85 % for magnesium stearate and therefore are within acceptable limits for the exploratory study.
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