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OPtimization od cultivation od microalgae cultures in photobioreactors
Byrtusová, Dana ; Márová, Ivana (referee) ; Kočí, Radka (advisor)
Presented diploma thesis is focused on the optimisation of Haematococcus pluvialis cultivations in different photobioreactors and on biotechnological production of astaxanthin. Theoretical part summarized the knowledge about optimal growth and production conditions of secondary metabolites. Followed research was focused on actual cultivation systems and on the possibilities of metabolite and nutrient monitoring. In experimental part the growth characteristic of the strain from Březova nad Svitavou (HMP-CCALA 375) was analyzed under optimal cultivation conditions on white and red light. During culture growth the profile and the concentration of carotenoid pigments were determined. The best yield of biomass was achieved in the cultivation on white light (0,939 g/l),carotenoids lutein and -carotene were observed as dominant pigments. In the next experiments optimal growth medium, temperature and light intensity were determined for cultivations of four chosen HMP strains from Germany, America, Africa and Switzerland. The most suitable cultivation medium was found BBM, oppositely the worst results were obtained with BG11. In previous experiments cultivation temperature 22 °C was determined as optimal value for comparative strain HMP – CCALA 375. Selected four strains were cultivated at 22 °C, as well as at 25 °C. Higher temperature was more optimal mainly for Switzerland, German and Africa strains. By analyzing of light intensity influence, it was found that the best increase of biomass was induced by the adaptation of culture on lower illumination (50 µmol photones•m^-2•s^-1) followed by higher light intensity (100 - 150 µmol photones•m^-2•s^-1). HMP from Switzerland showed the best growth results during all cultivation experiments, so this strain could be perhaps useful for industrial production of astaxanthin. In the last part of work, the influence of stress conditions on astaxanthin production by strain from Březova nad Svitavou (HMP – CCALA 375) was studied. Followed stress factors were used: high intensity of light (1 000 µmol photones•m^-2•s^-1), low nitrogen concentration (32,96 mg/l), addition of sodium chloride (0,5%), influence of sodium acetate (2,2 mM) and combination of sodium chloride and sodium acetate (0,5% NaCl, 2mM NaAc). Due to strong illumination (1 000 µmol photones•m^-2•s^-1) the best yield of astaxanthin was obtained (more than 20 mg/g). According to literature [103, 105] significant amount was also observed by addition of sodium acetate (9,2 mg/g). Oppositely minimal astaxanthin production was showed in presence of salt stress (3,8 mg/g). In followed experiments should be studied the influence of stress combinations on HMP – CCALA 375 strain as well as on other suitable strains of H. pluvialis with the aim to achieve the maximal yield of astaxanthin significant for large scale cultivation.
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Cell cycle of astaxanthin producing green alga Haematococcus pluvialis, culture media and cultivation conditions
Vávrová, Karolína ; Němcová, Yvonne (advisor) ; Pichrtová, Martina (referee)
Haematococcus pluvialis is unicellular green alga (Chlorophyceae, Chlamydomonadales), which can be found in ephemeral rock pools and birdbaths. It is the best natural producer of strong antioxidant astaxanthin, red secondary carotenoid used as coloring agent in aquaculture and poultry breeding. Astaxanthin also has various positive effects on human health. Haematococcus pluvialis has quite complex life cycle consisting of four life stages, biflagellated zoospores, non- motile round palmella stage, thick-walled akinetes (aplanospores, cysts) with high content of astaxanthin and small biflagellated gametes. Akinetes, which enable H. pluvialis to survive desiccation in its natural habitat, are formed in response to stress conditions such as high irradiance and temperature and nutrient depletion. Cells undergo dramatic ultrastructural changes during aplanospore formation. Chloroplast volume is decreased, synthesis of high amount of astaxanthin and fatty acids results in presence of lipid droplets that spread from the center to the periphery of the cell and thick cell wall containing algaenans is formed. Cultivation of H. pluvialis is often performed in two subsequent stages, green stage focused on biomass production and red stage focused on astaxanthin accumulation under stress conditions. There are...
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OPtimization od cultivation od microalgae cultures in photobioreactors
Byrtusová, Dana ; Márová, Ivana (referee) ; Kočí, Radka (advisor)
Presented diploma thesis is focused on the optimisation of Haematococcus pluvialis cultivations in different photobioreactors and on biotechnological production of astaxanthin. Theoretical part summarized the knowledge about optimal growth and production conditions of secondary metabolites. Followed research was focused on actual cultivation systems and on the possibilities of metabolite and nutrient monitoring. In experimental part the growth characteristic of the strain from Březova nad Svitavou (HMP-CCALA 375) was analyzed under optimal cultivation conditions on white and red light. During culture growth the profile and the concentration of carotenoid pigments were determined. The best yield of biomass was achieved in the cultivation on white light (0,939 g/l),carotenoids lutein and -carotene were observed as dominant pigments. In the next experiments optimal growth medium, temperature and light intensity were determined for cultivations of four chosen HMP strains from Germany, America, Africa and Switzerland. The most suitable cultivation medium was found BBM, oppositely the worst results were obtained with BG11. In previous experiments cultivation temperature 22 °C was determined as optimal value for comparative strain HMP – CCALA 375. Selected four strains were cultivated at 22 °C, as well as at 25 °C. Higher temperature was more optimal mainly for Switzerland, German and Africa strains. By analyzing of light intensity influence, it was found that the best increase of biomass was induced by the adaptation of culture on lower illumination (50 µmol photones•m^-2•s^-1) followed by higher light intensity (100 - 150 µmol photones•m^-2•s^-1). HMP from Switzerland showed the best growth results during all cultivation experiments, so this strain could be perhaps useful for industrial production of astaxanthin. In the last part of work, the influence of stress conditions on astaxanthin production by strain from Březova nad Svitavou (HMP – CCALA 375) was studied. Followed stress factors were used: high intensity of light (1 000 µmol photones•m^-2•s^-1), low nitrogen concentration (32,96 mg/l), addition of sodium chloride (0,5%), influence of sodium acetate (2,2 mM) and combination of sodium chloride and sodium acetate (0,5% NaCl, 2mM NaAc). Due to strong illumination (1 000 µmol photones•m^-2•s^-1) the best yield of astaxanthin was obtained (more than 20 mg/g). According to literature [103, 105] significant amount was also observed by addition of sodium acetate (9,2 mg/g). Oppositely minimal astaxanthin production was showed in presence of salt stress (3,8 mg/g). In followed experiments should be studied the influence of stress combinations on HMP – CCALA 375 strain as well as on other suitable strains of H. pluvialis with the aim to achieve the maximal yield of astaxanthin significant for large scale cultivation.
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