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Proposal of systems for targeted transoprt of compounds of sweet taste
Demová, Radoslava ; Hlaváček, Viliam (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on possibility of immobilization sweeteners on polymeric system. In the theoretical part information about sweeteners, carrier systems and the possibility of immobilization technique were reviewed. In the experimental part preparation of nanoparticles of polyhydroxybutyrate (PHB) was optimized. The PHB particles were characterized by dynamic light scattering (DLS). PHB particles were activated by plasma treatment. The surface morphology was studied using infrared and Raman spectroscopy. Immobilization of following substances with a sweet taste was tested: glucose, fructose, sucrose, mannitol, sorbitol and erythritol. From these compounds only sucrose was immobilized on PHB particles successfully. Prepared immobilized particles were exposed to the artificial stomach juice, intestinal juices and bile acids and amount of released sucrose was monitored. Finally, long-term stability prepared particles was measured and also the amount of sucrose released was determined.
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Effects of detergents on activity, thermostability and aggregation of immobilized lipases
Bančáková, Anna ; Voběrková, Stanislava (referee) ; Hermanová, Soňa (advisor)
Predmetom tejto diplomovej práce bolo štúdium vplyvu detergentov na aktivitu, termostabilitu a agregáciu voľnej a imobilizovanej formy komerčného preparátu lipázy izolovanej z mikroskopickej huby Rhizopus arrhizus. Teoretická časť obsahuje ucelenú rešerš popisujúcu štruktúru, mechanizmus účinku a priemyselný význam spomínanej hydrolázy spolu s popisom chemických účinkov detergentov, pričom dôraz bol kladený predovšetkým na skupinu neionogénnych detergentov s názvom tweeny. V experimentálnej časti bol študovaný efekt tweenov na rozpustnej a imobilizovanej forme RA lipázy. Imobilizácia spočívala v priamej adsorpcii enzýmu na neupravený nosič. Ako nosič bol použitý oxidovaný grafén ošetrený tweenom (tween 20, 60, 80). Aktivita enzýmu bola stanovená spektrofotometricky za pomoci substrátu p-nitrofenyl laurátu. Zvýšenie aktivity voľnej lipázy (104 % oproti maximálnej hodnote) bolo zaznamenané pri použití tweenu 20 o koncentrácii vysoko nad hodnotou kritickej micelárnej koncentrácie (10 mmol•dm-3). Na základe štúdie imobilizačných podmienok, boli nastavené ideálne parametre pre dosiahnutie účinnej imobilizácie v spojení s čo najvyššou lipolytickou aktivitou (koncentrácia enzýmu 0,1 mg•ml-1, fosfátový tlmivý roztok pH 7,2, koncentrácia tweenu 10,8 mmol•dm-3, čas imobilizácie 1 hodina). Obe formy lipázy vykazovali maximálnu aktivitu pri 35 °C. Optimálne pH sa u imobilizovanej lipázy posunulo na hodnotu 8, v porovnaní s voľnou formou, ktorej pH optimum bolo stanovené na 9. Tepelná stabilita vykazovala približne rovnaký priebeh u oboch foriem skúmanej hydrolázy. Avšak v prípade štúdia stability enzýmu pri dlhodobej úschove bolo po imobilizácii zistené výrazné zlepšenie tohto parametru.
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Inhibition of Hazardous Compounds in Alumino-Silicate Systems
Koplík, Jan ; Škvára, František (referee) ; Rovnaníková, Pavla (referee) ; Havlica, Jaromír (advisor)
The ability of alumino-silicate systems to immobilize hazardous compounds has been investigated since 1990s. The aim of this work is to develope alumino-silicate system (matrix) based on industrial waste products with ability to immobilize hazardous compounds (heavy metals). This ability of the matrix was confirmed by leaching tests based on the law 294/2005 Sb. Concentration of heavy metals in leachates was determined by ICP-MS method. Alumino-silicate system prepared in this work consists of high-temperature fly ash and blast furnace slag activated by mixture of alkaline activators (hydroxide and water glass). Matrixes were characterized by suitable analytic methods (XRD, SEM, FT-IR, DTA-TGA-EGA). The same analytic methods were used to describe the mechanism of immobilization of selected elements (Ba, Cu, Pb) in prepared systems.
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Use of some encapsulation techniques to controlled release of active substances in food and cosmetics products.
Skoumalová, Petra ; Rittich, Bohuslav (referee) ; Kráčmar, Stanislav (referee) ; Márová, Ivana (advisor)
The presented doctoral thesis is focused on preparation, characterization and application of organic micro- and nanoparticles as transport systems for active components and some their complex natural sources. Active component were packed into liposomes and polysaccharide particles. As active components were used caffeine, some drugs – clotrimazole and ibuprofen, further antioxidants and vitamins. Antimicrobial herbs and spices extract, antimicrobial peptides lysozyme, nisin and other antimicrobial ingredients were encapsulated too. Encapsulation of selected hydrolytic enzymes was tested, too. Particles were also used for encapsulation of probiotic strains Bifidobacterium breve and Lactobacillus acidophilus and prebiotic components. These prebiotics were co-encapsulated into capsules with probiotic cells. Natural extracts were encapsulated e.g. extracts of guarana, ginseng, goji, green barley, propolis, black, green and white tea, coffee, fruit and vegetable extracts. The efficiency of encapsulation was determined by HPLC/PDA and by spectrophotometry. Long-term stability of particles and amount of released component in model/real foods, in model cosmetic conditions and in a model physiological environment were monitored too. Size of prepared liposomes and polysaccharide particles was determined by dynamic light scattering and by light microscopy and electron microscopy, respectively. Stability of the particles was measured using a zeta potential. Also, analytical centrifugation was used to measurement of sedimentation velocity and stability of the prepared particles. The antimicrobial activity were tested using two Gram-positive (Bacillus subtilis, Micrococcus luteus), two Gram-negative (Escherichia coli, Serratia marcescens) bacteria and one fungal strains (Candida glabrata). For determining the antimicrobial properties of active component and prepared particles two the most widely used methods were used - agar diffusion method and broth dilution method. The viability of probiotic strains were performed using flow cytometry and fluorescence microscopy. Encapsulation of active component was successful in all types of particles. Liposome showed a very good long-term stability mainly in water conditions with neutral pH and polysaccharide particles were stable in acidic conditions. Prepared particles showed a very good stability in model stomach environment, while in model intestines environments particles were disintegrated and active component were released. Prepared particles with encapsulated caffeine as well as other tested antioxidants and vitamins could be used to modern types of energy drinks, food supplements and also for some cosmetics applications. Encapsulated antimicrobial components could be used for food application as well as for cosmetics and pharmaceutical application like antimicrobial wound formulation. Encapsulated enzymes can be used for controlled release of proteases in wound healing, as delivery systems in digestive tract and as a part of pharmaceutical preparative and food supplements for enzyme therapy. The study revealed that encapsulation of probiotics and also co-encapsulation of probiotics with prebiotics exhibited longer stability of particles and survival bacterial cells. So, prepared particles are suitable for use to food product with beneficial effects on the human body.
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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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Hydrogels of Humic Acids - Experimental Model and Application Form
Sedláček, Petr ; Klučáková, Martina (advisor)
The thesis deals with a utilization of hydrogels made of humic acids in both basic and applied research of this valuable natural material. The attention is paid to an interaction between the humic gel and cupric ions as the model heavy metal. The main experimental part focuses on an optimation of simple laboratory diffusion methods which serve as an innovative tool for modeling pollutants’ transport in natural humic environments. Various techniques were used in order to determine a diffusion coefficient of cupric ions in humic gel; the value is closely linked with the studied interaction between solid content of the gel and the diffusing species. Consequently, the diffusivity can be used as a standard parameter for basic reactivity mapping studies concerning humic substances. The final chapter of the thesis deals with a preparation of mixed reversible hydrogels formed by a reaction between humic acids and chitosan. These materials represent a suitable colloidal form for humic acids’ industrial and agricultural applications.
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The influence of different anions on fixation of Cu in alkali-activated blast furnace slag
Böhm, Petr ; Kotrla, Jan (referee) ; Koplík, Jan (advisor)
The work deals with the fixation of copper in alkali activated blast furnace slag and with the influence of anionts (sulphate, nitrate, chloride and oxide) to its immobilization. This is tested according to leaching tests ČSN EN – 12457 4. The concentration of copper in leachates was determined by inductively coupled plasma optical emission spectrometry. The aim of this work is to check the influence of addition (copper) to the resulting mechanical properties and also specify, how the heavy metal is bonded in the matrix. The structure was examined by scanning electron microscopy.
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Preparation of Microbial Metabolites from Waste Materials
Zichová, Miroslava ; Márová, Ivana (referee) ; Stloukal, Radek (referee) ; Rosenberg, Michal (advisor)
In this thesis the use of waste materials for the microbial production of important metabolites is reported. The first part is focused on the use of waste paper (a lignocellulosic material) as a non-traditional source for the production of bioethanol. The second part is focused on the immobilization of cellulolytic enzymes, which are used for the hydrolysis of lignocellulosic materials. First, the waste paper (cardboard) was pre-treated using a blender and a vibratory mill. The pre-treated cardboard was used for the production of ethanol by the method of simultaneous saccharification and fermentation. This method was optimized with free cells of Saccharomyces cerevisiae. Then strains suitable for the immobilization were selected. Strains of S. cerevisiae and Pichia kudriavzevii were immobilized by encapsulation into the polyvinyl alcohol carrier and tested again for the ethanol production by simultaneous saccharification and fermentation. In the second part of the work a carrier from waste polyethylene terephthalate bottles was prepared and used for the immobilization of the cellulolytic complex. The basic characteristics were determined, such as optimal pH and optimal temperature, storage, operational and thermal stability, enzyme kinetics and the mode of action of the enzyme. Compared to two other commercial carriers this carrier showed to be suitable for the immobilization of the cellulolytic complex.
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The influence of alkali activator on immobilization of metals in alkali activated blast furnace slag
Bystrianska, Emília ; Kalina, Lukáš (referee) ; Koplík, Jan (advisor)
In this work the influence of alkaline activator on immobilization of lead and copper in alkali-activated blast furnace slag was investigated. A total of five activators were used; sodium water glass, potassium water glass, sodium hydroxide, potassium hydroxide and sodium carbonate. The leaching test according to ČSN EN 12457-4 was used to evaluate the level of immobilization of heavy metals, the leached solutions were analyzed by ICP-OES. For a better understanding of immobilization, the selected samples were characterized by analytical methods (FTIR, XRD, SEM, XPS). It was found that the degree of immobilization Pb2+ and Cu2+ in AAS was very high, regardless of the type of alkaline activator used.
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