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Study on potential applications of glutamic acid polymer
Čangelová, Katarína ; Skoumalová, Petra (referee) ; Obruča, Stanislav (advisor)
The subject of the thesis is study of possible applications of isoform of glutamic acid polymer (-PGA). The theoretical part is focused on the properties of this biopolymer and potential applications in various areas. Producers and mechanisms of biosynthesis are also mentioned. In the experimental part, the polymer was firstly characterised by following methods: FT-IR spectroscopy, TGA, DSC and SEC-MALS. Its isoelectric point, antimicrobial activity and solubility in various solvents were also determined. The biopolymer was also precipitated by divalent cations and its interaction with oppositely charged CTAB surfactant was studied. The main experimental study was researching the effect of -PGA on viability of Saccharomyces cerevisiae and Lactobacillus rhamnosus under stress conditions by flow cytometry. The performed stresses included ethanol exposure, high temperature and freezing stress, in which its effects were compared to conventional cryoprotectants. The cells of the mentioned microorganisms were also stressed osmotically and exposed to model gastrointestinal juices - gastric, pancreatic and bile. The protective effects of -PGA on the cells were recorded in ethanol stress on Lactobacillus rhamnosus. Its excellent cryoprotection properties were confirmed and its protective effect of gastric juice exposure on Saccharomyces cerevisiae cells was also observed. At the end of the experimental part, -PGA/alginate beads suitable for encapsulation of probiotic bacteria and -PGA/chitosan nanoparticles for encapsulation of biologically active substances.
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Adsorption of microbial cells on model biological surfaces
Mikušová, Janka ; Krouská, Jitka (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis is creating sorption surface suitable for studying adsorption bacterial strain Lactobacillus rhamnosus, as representative probiotic bacterial strain. Included in the experimental part of this thesis was the process of creating sorption surface, according to the designed and especially optimized method. Optimization method comprised of preparing sorbent with sorption surface including mucin, on which was the bacterial strain Lactobacillus rhamnosus bound to, using specific interaction. UV-VIS spectrophotometry was utilized in the optimization of the sorption surface preparation for monitoring losses of mucin in solution that happens during the bondation on used substrate. Designed sorption surfaces were subjected to various physical-chemical analyses, which roles were displaying and characterisation of surface and confirming the presence of mucin. One of the major components, in the process of observing and characterization of changes in surface structure of the sorption surface, was infrared spectroscopy with Fourier transformation. Scanning electron microscopy was used for more detailed observation of the surface structure, created by adhesive interactions, which participate in probiotic bacteria adhesion. Finally, the created surfaces were used in pilot experiment, during which, the kinetics in growing bacterial culture with and without the presence of sorbent using microcalorimetry were observed. Designed sorbent appears to be a suitable mediator for detailed characterisation of bacterial adhesion, which is the first step in creating bacterial biofilm.
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Active preparatives based on koji fermentation and medical mushrooms extracts
Živná, Kristýna ; Dzurická, Lucia (referee) ; Hoová, Julie (advisor)
This bachelor's thesis deals with the optimization of the growth of the rare species fungus of the hedgehog mushroom on cereal substrates for the purpose of the subsequent to cultivation of lactic acid bacteria. The theoretical part is focused on the description of the rare fungus species and the use of the cereals as substrate and the characterization of their active substances. It also deals with lactic fermentation and its use. In the experimental part, the preparation of the cereal substrate for the cultivation of the hedgehog mushroom was optimized. The method of inoculation of the cereals substrate with liquid mycelium in combination with plate mycelium was chosen as the most applicable. In this combination, the substrate does not dry out and grows evenly from both sides of the substrate. The composition of the cereal substrate with grown mycelium was characterized (antioxidant activity, carbohydrates, proteins). Finally, the substrate was inoculated with lactic bacteria. The lactic bacteria added nutritional value to the product. Fermentation products (antioxidant activity, carbohydrates, proteins) were characterized, and bacterial viability was analysed.
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Study on potential applications of glutamic acid polymer
Čangelová, Katarína ; Skoumalová, Petra (referee) ; Obruča, Stanislav (advisor)
The subject of the thesis is study of possible applications of isoform of glutamic acid polymer (-PGA). The theoretical part is focused on the properties of this biopolymer and potential applications in various areas. Producers and mechanisms of biosynthesis are also mentioned. In the experimental part, the polymer was firstly characterised by following methods: FT-IR spectroscopy, TGA, DSC and SEC-MALS. Its isoelectric point, antimicrobial activity and solubility in various solvents were also determined. The biopolymer was also precipitated by divalent cations and its interaction with oppositely charged CTAB surfactant was studied. The main experimental study was researching the effect of -PGA on viability of Saccharomyces cerevisiae and Lactobacillus rhamnosus under stress conditions by flow cytometry. The performed stresses included ethanol exposure, high temperature and freezing stress, in which its effects were compared to conventional cryoprotectants. The cells of the mentioned microorganisms were also stressed osmotically and exposed to model gastrointestinal juices - gastric, pancreatic and bile. The protective effects of -PGA on the cells were recorded in ethanol stress on Lactobacillus rhamnosus. Its excellent cryoprotection properties were confirmed and its protective effect of gastric juice exposure on Saccharomyces cerevisiae cells was also observed. At the end of the experimental part, -PGA/alginate beads suitable for encapsulation of probiotic bacteria and -PGA/chitosan nanoparticles for encapsulation of biologically active substances.
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Adsorption of microbial cells on model biological surfaces
Mikušová, Janka ; Krouská, Jitka (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis is creating sorption surface suitable for studying adsorption bacterial strain Lactobacillus rhamnosus, as representative probiotic bacterial strain. Included in the experimental part of this thesis was the process of creating sorption surface, according to the designed and especially optimized method. Optimization method comprised of preparing sorbent with sorption surface including mucin, on which was the bacterial strain Lactobacillus rhamnosus bound to, using specific interaction. UV-VIS spectrophotometry was utilized in the optimization of the sorption surface preparation for monitoring losses of mucin in solution that happens during the bondation on used substrate. Designed sorption surfaces were subjected to various physical-chemical analyses, which roles were displaying and characterisation of surface and confirming the presence of mucin. One of the major components, in the process of observing and characterization of changes in surface structure of the sorption surface, was infrared spectroscopy with Fourier transformation. Scanning electron microscopy was used for more detailed observation of the surface structure, created by adhesive interactions, which participate in probiotic bacteria adhesion. Finally, the created surfaces were used in pilot experiment, during which, the kinetics in growing bacterial culture with and without the presence of sorbent using microcalorimetry were observed. Designed sorbent appears to be a suitable mediator for detailed characterisation of bacterial adhesion, which is the first step in creating bacterial biofilm.
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Vliv různých forem glutathionu na kulturu Lactobacillus
Lacková, Zuzana
The thiol tripeptide glutathione was identified in majority of organisms, including microorganisms, and its major role is to maintain the redox equilibrium in a cell. Similar properties are attributed to Lactobacillus rhamnosus, which also exhibits antioxidant potential, and thus acts favorably against oxidative stress. In our studythe effect of GSH and GSSG (0; 3; 300 and 3000 uM) on the culture of L. rhamnosus CCM 4185 was evaluated. Using the microbiological, biochemical and analytical techniques, it was found that increased addition of both glutathione forms causes decrease of glucose and proteins levels, pointing to increased metabolical activity of bacterial cells, as a response on glutathiones presence in extracellular space. The obtained results revealed that glu-tathione causes more positive than negative effects towards L. rhamnosus culture.
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