National Repository of Grey Literature 8 records found  Search took 0.00 seconds. 
Utilizing of Electron Microscopy for Nanoparticle Detection in Selected Food
Boriková, Natália ; Hrabalová, Vendula (referee) ; Dzurická, Lucia (advisor)
This bachelor thesis deals with the detection of nanoparticles in selected food products using electron microscopy. Specifically, silver pearls, silver powder and food grade whiteness were selected for this purpose. Nanoparticles themselves can have a negative effect on the human body in high concentrations. They need to meet certain legislative standards. The main focus of this bachelor thesis is how nanoparticles could be detected in food. The theoretical part provides an insight into the properties of nanoparticles, their applications and describes methods for their determination, primarily with an emphasis on electron microscopy. In the practical part, solvents with artificially added nanoparticles were prepared and served as standards. Two samples were prepared from selected foods – with and without the addition of nanoparticles. They were analysed using low-energy electron microscope of LVEM 25E type along with elemental analysis using energy dispersive spectroscopy (EDS). The results provide the compositions of the foodstuffs in question and information on the presence of nanoparticles on their own. This research contributes to a better understanding of their characteristics and safety.
Effect of culture medium composition on selected characteristics of microbial culture of Aneurinibacillus sp.
Sklárová, Viktória ; Hrabalová, Vendula (referee) ; Buchtíková, Iva (advisor)
The aim of this bachelor thesis was to identify the key components of the culture medium and to optimize the composition of the culture medium for the thermophilic strain Aneurinibacillus sp. AFN2. The theoretical part discusses extremophilic microorganisms, especially thermophilic ones, and their ability to produce polyhydroxyalkanoates, followed by a description of the structure, properties, synthesis, and applications of polyhydroxyalkanoates. In the experimental part of the work, cultivations were performed to optimize the production medium, inoculation ratio, inoculation culture time and the effect of medium cooling on the production of polyhydroxyalkanoates. Finally, a last cultivation was performed in which the initial and optimized cultivation conditions were compared. All cultivations were performed on mineral and complex production medium. After a series of experiments, the optimized conditions for the complex medium were determined to be the medium composition without NaCl addition, an inoculation ratio of 10%, an inoculation culture cultivation time of 24 hours. The optimum conditions of mineral medium were determined as follows, the composition of the mineral medium remained unchanged from the initial one, the optimum inoculation ratio was determined to be 15% and the inoculum culture cultivation time was established to be 24 h.
Characterization of bacterial strains obtained in evolutionary engineering
Hrabalová, Vendula ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with application of evolutionary engineering on PHA producing bacterial strains. Two bacterial strains, Cupriavidus necator H16 and Halomonas halophila, were chosen for the evolutionary experiments. Copper cations (Cu2+) and sodium chloride (NaCl) were chosen as the selective pressure for C. necator H16; acetic acid (AA) and levulinic acid (LA) for Halomonas halophila. The adapted strains were during long-time evolutionary experiments characterized by GC-FID and SEC-MALS. The growth of the adapted strains was studied by the mean of optical density measurement. The amount of viable cells was determined by spectral FC after their expositon to selected stress factors. Specific enzyme activities of enzymes involved in citrate and glyoxalate cycle, enzymes generating NADPH, LA metabolism enzyme and PHA biosynthesis enzymes were determined. The adapted strains were compared with the wild-type of strains. The successfull adaptation of C. necator H16 adapted to Cu2+ was detected. Biomass and PHA production of both wild and adapted H. halophila strains cultivated in lignocellulosis waste were determined. It was found out that H. halophila adapted to the LA is capable of producing more PHA than the wild strain of this bacteria.
Influence of PHA accumulation on resistance of bacteria against selected antibacterial drugs
Hrabalová, Vendula ; Kučera, Dan (referee) ; Obruča, Stanislav (advisor)
The aim of this bachelor thesis was to study the effect of bactericidal drugs on bacteria from the genus C. necator H16 and its mutant genus PHB-4. The genus H16 shows ability to accumulate polyhydroxyalkanoates (PHA) in the form of granules while the genus PHB-4 lacks to show this ability. The theoretical part of the bachelor thesis is focused on the effect of antibiotics on bacteria in general and the determination of susceptibility of bacteria to antimicrobial substances. The effect of three specific antibiotics (nisine, streptomycin and penicillin) on both bacterial strains was tested in the experimental part. The viability of bacteria was determined by the spread plate method and flow cytometry. Agar diffusion test and broth microdilution test were used to test the susceptibility of bacteria. It was concluded that the accumulation of PHA decreases the tolerance of bacteria to antimicrobial substances because the genus C. necator H16 is more susceptible to streptomycin and penicillin then the strain C. necator PHB-4.
Biotechnological production of PHA from waste substrates
Krejčiřík, Roman ; Hrabalová, Vendula (referee) ; Obruča, Stanislav (advisor)
The presented bachelor thesis deals with the study of polyhydroxyalkanoates using wine grape pomace extract. The thesis aims to determine whether it is possible to use wine grape pomace extract as a substrate for polyhydroxyalkanoates (PHA) production. For this research, four thermophilic bacterial strains were selected such as Schlegelella thermodepolymerans, Caldimonas meghalayensis, natural isolate labeled as 34, and Tepidimonas taiwanensis, from which the most suitable bacterium was subsequently selected. The best transformation of residual sugars showed T. taiwanensis, and therefore it was used for all the further fermentation. The extracts were prepared out of wine marc of Veltlínské červené rané, Müller Thurgau, Pálava, Sauvignon, Rulandské bílé, Frankovka (rosé), Frankovka (red wine). The highest PHA concentration was detected after fermentation with concentrated extracts of Sauvignon and Rulandské bílé. Fermentation processes in other extracts were most likely inhibited by the components they contained. Optimization was performed by dilution of extracts with water. The highest concentrations of PHA while using dilute extracts were achieved with the extract from different kinds of Frankovka (rosé) and Frankovka (red wine).
Biotechnological production of PHA from waste substrates
Krejčiřík, Roman ; Hrabalová, Vendula (referee) ; Obruča, Stanislav (advisor)
The presented bachelor thesis deals with the study of polyhydroxyalkanoates using wine grape pomace extract. The thesis aims to determine whether it is possible to use wine grape pomace extract as a substrate for polyhydroxyalkanoates (PHA) production. For this research, four thermophilic bacterial strains were selected such as Schlegelella thermodepolymerans, Caldimonas meghalayensis, natural isolate labeled as 34, and Tepidimonas taiwanensis, from which the most suitable bacterium was subsequently selected. The best transformation of residual sugars showed T. taiwanensis, and therefore it was used for all the further fermentation. The extracts were prepared out of wine marc of Veltlínské červené rané, Müller Thurgau, Pálava, Sauvignon, Rulandské bílé, Frankovka (rosé), Frankovka (red wine). The highest PHA concentration was detected after fermentation with concentrated extracts of Sauvignon and Rulandské bílé. Fermentation processes in other extracts were most likely inhibited by the components they contained. Optimization was performed by dilution of extracts with water. The highest concentrations of PHA while using dilute extracts were achieved with the extract from different kinds of Frankovka (rosé) and Frankovka (red wine).
Characterization of bacterial strains obtained in evolutionary engineering
Hrabalová, Vendula ; Sedláček, Petr (referee) ; Obruča, Stanislav (advisor)
This diploma thesis deals with application of evolutionary engineering on PHA producing bacterial strains. Two bacterial strains, Cupriavidus necator H16 and Halomonas halophila, were chosen for the evolutionary experiments. Copper cations (Cu2+) and sodium chloride (NaCl) were chosen as the selective pressure for C. necator H16; acetic acid (AA) and levulinic acid (LA) for Halomonas halophila. The adapted strains were during long-time evolutionary experiments characterized by GC-FID and SEC-MALS. The growth of the adapted strains was studied by the mean of optical density measurement. The amount of viable cells was determined by spectral FC after their expositon to selected stress factors. Specific enzyme activities of enzymes involved in citrate and glyoxalate cycle, enzymes generating NADPH, LA metabolism enzyme and PHA biosynthesis enzymes were determined. The adapted strains were compared with the wild-type of strains. The successfull adaptation of C. necator H16 adapted to Cu2+ was detected. Biomass and PHA production of both wild and adapted H. halophila strains cultivated in lignocellulosis waste were determined. It was found out that H. halophila adapted to the LA is capable of producing more PHA than the wild strain of this bacteria.
Influence of PHA accumulation on resistance of bacteria against selected antibacterial drugs
Hrabalová, Vendula ; Kučera, Dan (referee) ; Obruča, Stanislav (advisor)
The aim of this bachelor thesis was to study the effect of bactericidal drugs on bacteria from the genus C. necator H16 and its mutant genus PHB-4. The genus H16 shows ability to accumulate polyhydroxyalkanoates (PHA) in the form of granules while the genus PHB-4 lacks to show this ability. The theoretical part of the bachelor thesis is focused on the effect of antibiotics on bacteria in general and the determination of susceptibility of bacteria to antimicrobial substances. The effect of three specific antibiotics (nisine, streptomycin and penicillin) on both bacterial strains was tested in the experimental part. The viability of bacteria was determined by the spread plate method and flow cytometry. Agar diffusion test and broth microdilution test were used to test the susceptibility of bacteria. It was concluded that the accumulation of PHA decreases the tolerance of bacteria to antimicrobial substances because the genus C. necator H16 is more susceptible to streptomycin and penicillin then the strain C. necator PHB-4.

See also: similar author names
2 Hrabalová, Veronika
1 Hrabalová, Vlastimila
Interested in being notified about new results for this query?
Subscribe to the RSS feed.