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Growth characteristics of thermophilic microorganisms
Kuchtová, Ludmila ; Vítová, Eva (referee) ; Babák, Libor (advisor)
The aim of this work was focused on study of influence of cultivation conditions on growth of thermophilic bacteria Thermus aquaticus, Thermus scotoductus, Geobacillus thermodenitrificans and Geobacillus thermocatenulatus in cultivation medium recommended by Czech Collection of Microorganisms (CCM). The change of concentration of biomass during cultivation with various pH of media, cultivation temperature, agitation rate and with addition of glucose to medium during cultivation in Erlenmayer flasks was observed. Results served for determination of optimal growth conditions for each microorganism. After optimal growth conditions were obtained, cultivations in fermenter were performed. Growth curves were made from values of absorbance and dry weight of samples.
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Pretreatment of polysaccharide waste materials to maximize of hydrolysis products
Myslivcová, Pavla ; Trachtová, Štěpánka (referee) ; Babák, Libor (advisor)
This thesis deals with study of the polysacharidic waste material pretreatment in order to maximize the hydrolysis products. It has been chosen a pastry as a waste material, specifically rolls and bread. Pastry was pretreated by milling and 15% w/v suspension of pastry in the water was prepared. Then several types of hydrolysis were performed with suspensions. Products of hydrolysis were characterized by spectrophotometric method of Somogyi-Nelson and efficiency of hydrolysis was compared. Three acids (H2SO4, HNO3, HCl) and two alkalis (NaOH, KOH) in three various concentration were used for the chemical hydrolysis. Microwave and ultrasound were chosen for the physical hydrolysis.
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Thermophilic microorganisms application to biodegradation
Varmužová, Tamara ; Márová, Ivana (referee) ; Babák, Libor (advisor)
This thesis is focused on study of biodegradability of modified polyurethane elastomeric films in synthetic medium with minerals and vitamins on tempered shaker by mixed thermophilic aerobic bacterial culture Bacillus and Thermus genera. In most cases addition of all used fillers (carboxymethyl cellulose, hydroxyethyl cellulose, acetylated cellulose, acetylated starch and glutein) led to increased biodegradability of elastomeric films with modifying agent in comparison with elastomeric films without modifying agent (referential). The growth of cultures was strongly increased in presence of elastomeric films modified by 10 % acetylated cellulose and 10 % carboxymethyl cellulose. Elastomeric film biodegradation mechanism included probably two stages: abiotic destruction of elastomeric films and consequent utilization of degradation products by bacterial culture.
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Biodegradability of bacterial natural and modified polyesters and their composites
Pala, Martin ; Babák, Libor (referee) ; Obruča, Stanislav (advisor)
Presented work was focused on biodegradability of bacterial natural and modified polyesters and their composites. The first part of the work was focused on study of influence of PHA granules structure on their biodegradability using selected enzymes and influence of physiological conditions on PHA stability. Overall, tested polymer either in crytalinne or amorphous phase seems to be rezistent to attack of seleced hydrolytic enzymes such as lipases or proteases and is stable in simulated physiological fluids as well. Because of thies results, it is possible to use tested PHA materials in biomedical applications requiring rather resistant biomaterials. Second part of the work was focused on microbial degradation of modified PHA materials considering their potential environmental impact. Both mixed thermophillic culture originaly used in wastewater treatment plant and bacterial strain Delftia acidovorans were employed for biodegradation tests. Composites containing chlorine PHB and PHB films modified using plasticizers were tested. Films containing chlorine PHB cause inhibition of biomass growth to both tested cultures. The highest rate of degradation (31%) was observed in presence of bacterial culture with film containing 10% chlorine PHB. The results show that used microbial population is important factor affecting biodegradability.
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A study of the possibility of waste pastries using for the bioproduction of selected metabolites
Hudečková, Helena ; Vránová, Dana (referee) ; Babák, Libor (advisor)
The aim of this diploma thesis was to study the possibility of using waste bread to bioproduction of selected metabolites. As bakery waste was used waste bread that came from coffee-house “Zastávka”. Bread was pre-treated by grinding into small particles and then it was made to form 15% w/v suspension, which was subjected to enzymatic hydrolysis. For the hydrolysis has been used the -amylase for liquefaction of the substrate and that was followed by a glucoamylase which sacharificated the substrate. There have been several methods of hydrolysis from which was chosen the optimal method for pre-treatment of the substrate prior to fermentation. The effectivity and a process of hydrolysis were determined spectrophotometrically by Somogyi-Nelson method. Final yields of glucose from hydrolysis were determined by HPLC method. Enzymatic hydrolysis was followed by fermentation, which was carried out in two ways, namely by adjusting the pH of the hydrolyzate to pH 5, and without pH adjustment. During the fermentation was carried out sampling in which was determined the content of glucose, glycerol and ethanol by HPLC method. The yeasts Saccharomyces cerevisiae were used for the fermentation which was performed at 30 °C. High yield of glucose was achieved by hydrolysis in two steps (70,28 gl-1), but for the fermentation was used mixed hydrolysis (second method of mixed hydrolysis) with yield 67,94 gl-1. High ethanol yield was achieved during fermentation without treatment pH, namely 31,5 gl-1.
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Importance and utilization of cellulases
Stuchlíková, Olga ; Babák, Libor (referee) ; Omelková, Jiřina (advisor)
The theoretical part of my bachelor thesis focuses on studying plant cells and polysaccharides, from which the cell wall is made of. The main attention is held on cellulose. Secondly, cellulases and microorganisms, which produce these enzymes, are mentioned. This work also deals with the actual use of cellulases in industry and agriculture. The last chapter of the theoretical part is devoted to immobilization, immobilized enzymes and their use in practice. The practical part of my bachelor thesis focuses on determination of basic properties of commercially used enzyme Celluclast 1.5 L. The temperature and pH optimum and temperature and pH stability were determined experimentally. The attention is also held on immobilization of these cellulases on synthetically prepared carrier „Sorsilen“. Subsequently, basic characteristics were determined as well as for soluble form of commercial enzyme.
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Influence of total leaf nitrogen and non-structural carbohydrates on Rubisco content and its activity under ambient and elevated concentrations of carbon dioxide
Vičíková, Magda ; Babák, Libor (referee) ; Hrstka, Miroslav (advisor)
This diploma thesis examines influence of content of leaf nitrogen and non-structural carbohydrates on Rubisco activity and its content under impact of ambient (A = 385 µmolCO2 mol-1) and elevated (E = 700 µmolCO2 mol-1) concentrations of carbon dioxide in needles of Norway spruce (Picea abies L.). The Rubisco activity was determined spectrophotometrically, the Rubisco content by using SDS-PAGE, the content of non-structural carbohydrates by using the anthron method and total leaf nitrogen was determined by using the Kjeldahl method. The Rubisco activity in needles of Norway spruce did not show acclimation on elevated concentration of carbon dioxide, but the activity was elevated concentration of carbon dioxide stimulated during the growing season. The acclimation was proved by Rubisco content, its content was significantly lower in needles cultivated under elevated carbon dioxide. Content of total leaf nitrogen was statistically significantly lower in needles of Norway spruce cultivated under elevated carbon dioxide then in needles cultivated under ambient concentration of carbon dioxide. On the contrary, the content of non-structural carbohydrates was significantly higher in needles cultivated under elevated concentration of carbon dioxide then in variant A. Seasonal changes of Rubisco content depended on content of non-structural carbohydrates, the Rubisco content decreased with increasing content of non-structural carbohydrates. No dependence was detected between seasonal changes of the total leaf content and the Rubisco content.
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A bioconversion study of cellulosic waste to ethanol using yeasts systems
Čalová, Iveta ; Vítová, Eva (referee) ; Babák, Libor (advisor)
This diploma thesis deals with the optimization of the production of ethanol from waste paper using yeast. There were used 4 kinds of paper as a substrate - office paper, non-recycled workbook, recycled workbook and newspaper. All papers were pretreated with the following procedures: grinding, microwaves + NaOH, microwave + H2SO4 and microwave + H2SO4 + NaOH. The glucose concentration was determined in enzymatic hydrolysis by HPLC. Saccharomyces cerevisiae were chosen for ethanol production. The production of ethanol was carried out with all the pretreated papers in simultaneous saccharification and fermentation. During hydrolysis, the pretreated papers have reached the highest results in the combination with microwave + H2SO4 + NaOH. Non-recycled workbook was the only exception, where the highest concentration of glucose has been obtained by the pretreatment of microwaves + H2SO4. Following results have been acquired: office paper 24,69 gdm-3, non-recycled workbook 22,47 gdm-3, recycled workbook 16,94 gdm-3 and newspapers 15,36 gdm-3. SSF was carried out again with all the papers and their pretreatments. The highest concentration of ethanol has been achieved in microwave pretreatment + H2SO4 + NaOH. The highest overall concentration has been gained from the office paper, amounted to 16,98 gdm-3. The maximum concentration of ethanol for non-recycled workbook has been 15,25 gdm-3, for recycled workbook 12,2 gdm-3 and for newspapers 12,59 gdm-3.
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Thermotolerant strains application for preparation of selected metabolites on waste hydrolysates
Musilová, Kristína ; Vítová, Eva (referee) ; Babák, Libor (advisor)
This Bachelor´s Thesis deals with the preparation of the selected metabolite on hydrolysates of orange fruit waste, specifically on orange peel hydrolysates using thermotolerant strains. The thermotolerant Bacillus coagulans strain having lactic acid as the primary metabolite, a substance with a great perspective, was selected for the fermentation process for its exceptional properties. At the beginning of the experiment, optimal conditions for the growth of the selected microorganism were determined; these were applied during the fermentations. Several fermentations were performed under various conditions until those conditions were determined, in which lactic acid was produced. The fermentation production was determined by the HPLC method and the saccharide decrease by the Somogyi-Nelson method. To achieve lactic acid production, it was necessary to extract the orange peels by an organic agent before fermentation, in order to eliminate substances causing inhibition of micro-organism growth. Higher yields were achieved by the SHF method, but the highest by using the Lactobacillus casei strain.
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Selected bioengineering characteristics of lactic acid bacteria
Šťásková, Lucie ; Vítová, Eva (referee) ; Babák, Libor (advisor)
The diploma thesis deals with the growth of biomass and production of selected metabolit–lactic acid by thermophilic bacteria Bacillus coagulans. The resulting selected metabolite was determined by HPLC method. Cultivations of this genus were performed on synthetic media, where the influence of carbohydrate used as carbon source was tested. Lactose was more suitable fot growth of biomass and glucose for production of lactic acid. On natural whey media the influence of different conditions were tested. The highest yields of biomass and production of lactic acid were observed on enriched whey medium. The last part deals with comparing the production of biomass and metabolites, depending on the volume of media. There were compared selected bioengineering characteristics of all cultivations.
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