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Comparison of microbial metabolic production from waste and powder whey
Elefantová, Petra ; Vítová, Eva (referee) ; Babák, Libor (advisor)
The master’s thesis discusses the comparison of microbial metabolic production from waste and powder whey. Whey is obtained as a by-product of cheese production. Lactose (preferably whey) using lactic acid bacteria (eg. Lactobacillus) under suitable temperature conditions is converted to lactic acid. Effect of temperature, effect of salts and effect of yeast extract on lactic acid production by L. casei were investigated. HPLC metod was determined lactid acid. In the practical part were used bacteria of the genus Lactobacillus. It was found that for dried and waste whey is the optimal temperature of 35 °C. At this temperature is the greatest gain of lactic acid. The highest concentration of lactic acid was obtained by using 20 g of yeast extract for dried whey and for waste whey were used 24 g of yeast extract. When monitoring the effect of salt concentration on the production of lactic acid, it was found that using only MnSO4·H2O gain most of lactic acid.
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Utilization of various methods of porosimetry in investigation of internal structure of biopolymer hydrogels
Zahrádka, Jan ; Pekař, Miloslav (referee) ; Sedláček, Petr (advisor)
The main aim of the thesis was to select, optimize and test suitable methods for studying inner structure of hydrogel materials. The study of the size of pores with potential use in fundamental and applied research of these materials is the central focus of the thesis. Firstly, a literature search was done in order to collect basic information about usefulness of the individual methods. On the basis of this literature search, the experimental part of the work was divided into several steps. First, selected methods of conventional porosimetry (mercury intrusion porosimetry, BET analysis and DSC thermoporometry) were applied on reference porous materials and the results obtained by the individual methods were compared. The methods optimized with the use of these reference materials were then utilized in the analysis of porosity of model hydrogels based on polyvinyl alcohol. Based on the results of this analysis, the usability and benefits of the individual methods were discussed with respect to the sample preparation, time and financial demands, and also from the viewpoint of compliance of the determined pore sizes with the range of sizes declared for the physical PVA gels.
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Interactions between hyaluronan and cetrimide
Adamcová, Zuzana ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
Interactions between hyaluronan and cationic Cetrimide were studied using fluorescence spectroscopy and turbidimetry in model physiological solution (0,15 M NaCl) and water. Results obtained in water showed strong electrostatic interactions before reaching CMC of the surfactant, which were screened in presence of salt due to high ionic strenght of the solution. Behavior of Cetrimide-hyaluronan systems was compared with the pure TTAB in equivalent system. It was found, that changes in Cetrimide-HA system occure at lower concentrations of the surfactant than in TTAB-HA system. This was probably caused by presence of small amount of CTAB in Cetrimide.
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Investigation of Polyelectrolytes Interactions with Cationic Aminogroups-containing Amphiphiles
Zeman, Jan ; Běťák, Jiří (referee) ; Chytil, Martin (advisor)
The study deals with interactions of polyelectrolytes polystyrene sulfonate and hyaluronic acid with nitrogenic amphiphilic substances, represented by lysine and albumine. To study the interactions pH-metry, conductance, viscositic and turbidity measurement, DLS and reometry were used. All mixtures of different concentrations were measured and the data were compered with data obtained from measurement of samples with amphiphilic sumstances without polyelectrolytes. Observed interactions occured in the aminoacid concentrations between 0 to 20 mmoldm-3, then the PSS interaction groups were fully bonded by lysine and no more interactions were recognized. The same behaviour were observed in albumine solutions with concentration under 2 gdm-3.
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Hyaluronan ion complexes
Cimalová, Jana ; Sedlařík, Vladimír (referee) ; Pekař, Miloslav (advisor)
This diploma thesis is focused on the study of physical and chemical properties of hyaluronan and cationic surfactant. As the cationic surfactant Septonex was used. The influence of the environment on the system, the effect of molecular weight of hyaluronan, and its concentration was studied. Then, the study of the influence and the effects of concentration of Septonex on the interaction of hyaluronan-surfactant followed. Different methods of measurement were chosen to characterize these ionokomplexes. The critical micelle concentration of the surfactant itself was measured, and then also with the addition of hyaluronan by spectrofluorimetry with fluorescent probe pyren. It was found, that hyaluronan forms gel with Septonex. On this basis, gels were prepared for three different molecular weights of hyaluronan – 300 kDa, 806 kDa and 1697 kDa. Gels were prepared in a ratio of hyaluronan – surfactant 1:1. In gels prepared in this way, the influence of environmental water and 0.15 M NaCl was studied and it was found that at 0.15 M NaCl clear gels are formed. Selected samples of the gels were then measured with oscillatory testing and the rheological behavior of gels of Septonex was studied. As the last method the turbidimetric measurement was chosen, which characterized the turbidity point in the gradual addition of Septonex to sodium hyaluronate solution. Again, the effect of the molecular weight of hyaluronan and its concentration in two environments - water and 0.15 M NaCl was evaluated. It was found that 0,15 M NaCl suppresses formation of turbidity and formation of precipitates.
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Characterization of hyaluronan interactions with albumin
Valentová, Kristýna ; Kratochvílová, Romana (referee) ; Chytil, Martin (advisor)
This bachelor thesis focuses on the research of physical interactions between hyaluronic acid and a protein albumin. In order to investigate these interactions following methods were used: pH and conductivity measurement, viscosimetry, turbidimetry and rheometry. The interactions were observed in solutions of fixed albumin concentration 1.0 gdm-3 and varying concentrations of hyaluronic acid from 0.1 to 2.0 gdm-3. Results were compared with a solution of hyaluronic acid without the addition of albumin. The results show that there are interactions between hyaluronic acid and albumin solutions, especially for those containing high molecular weight hyaluronic acid. The interactions exhibited a change in viscosity of solutions. We can see a reduction in viscosity after adding albumin to the reference solutions. The reduction is noticeable even in the low molecular weight HA solutions, but is not so significant.
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Preparation and characterization of quatsomes
Havlíčková, Anna ; Szabová, Jana (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with preparing and characterizing quatsomes and similar vesicular systems. The preparation consisted of weighing an equimolar amount of sterol and surfactant, hydration with deionized water, and subsequent sonication with an ultrasonic probe with an energy of 5, 10 and 15 kJ. In this work, two types of quatsomes were prepared, the first contained equimolar amounts of cholesterol and cetyltrimethylammonium bromide (CTAB), and the second consisted of cholesterol carbethopendecinium bromide (Septonex). The optimal dispersion energy of 10 kJ was selected for both types based on turbidity measurements, visual observation and dynamic and electrophoretic light scattering analysis. Furthermore, the observed properties were found to be constant from day 7 after sonication. In addition to quatsomes, similar vesicles were prepared, which contained a surfactant in the form of a sulfate salt. Once again, two types were prepared, the first containing sodium dodecyl sulfate (SDS) and cholesterol, the second sodium tetradecyl sulfate (STS) and cholesterol. Based on the same measurements as for quatsomes, optimal dispersion energy of 10 kJ was selected. Furthermore, mixtures with different ratios of cholesterol and a given surfactant were prepared, in which the effect of cholesterol addition was monitored. The analysis of these mixtures was performed by the same methods as the analysis of quatsomes.
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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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Hyaluronan-Micelle Aggregates and their Potential for Nanomedicine Applications
Pilgrová, Tereza ; Burgert, Ladislav (referee) ; Reháková, Milena (referee) ; Pekař, Miloslav (advisor)
This thesis deals with the study of preparation and characterization of hyaluronan-micelle aggregates. The theoretical part deals with drug delivery systems, characterization of used materials and methods especially fluorescence spectroscopy, dynamic light scattering and turbidimetry. Methods of determination of measured data are summarized in the experimental section. The result section is divided into two subsections dedicated to different preparation methods of hyaluronan-surfactant complexes. Induced aggregates of hyaluronan with Septonex are characterized in terms of their origin and stability, and the results are compared with previously studied surfactants CTAB. In the second part are discussed so-called decorated micelles, their formation, properties and stability.
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Complex structural characterization of hydrogels based on semi interpenetrating biopolymer networks.
Trudičová, Monika ; Krzyžánek, Vladislav (referee) ; Sedláček, Petr (advisor)
The content of this diploma thesis was testing the applicability of available structural analysis techniques on a appropriate model hydrogel system. The main aim was to evaluate the advantages and disadvantages of selected structural analysis techniques and the influence of the composition change of the hydrogel system on its internal structure. Semi-interpenetrated hydrogels based on agarose of different concentration were chosen as model system, this type of material was chosen for simple and repeatable preparation and also for its application potential. Electron microscopy (SEM, cryoSEM), mercury porosimetry and turbidimetry were chosen as structural analysis techniques. Experimental results could be used to improve knowledge about the influence of hydrogel composition on its structure and the comparison of chosen techniques will be used for the choice of appropriate structural analysis in the future, which will be applicable to other hydrogel systems as well.
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