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Influence of biodegradation of polyhydroxyalkanoates on soil properties and composition
Denková, Pavla ; Doležalová Weissmannová, Helena (referee) ; Kučerík, Jiří (advisor)
Biodegradable plastics are presented as a promising replacement for synthetic polymers. In soil, they are expected to be fully degraded by micro-organisms within a short time and to be inherently harmless to the environment. However, this assumption needs to be verified, and it is important to pay attention to the impact on soil´s biota as well as the effect of the biodegradation process could have on soil properties, composition and structure. In this work was studied the effect of biodegradation of poly(R-3-hydroxybutyrate), (P3HB), belonging to the group of polyhydroxyalkanoates, on the structure and physicochemical properties of soil. P3HB particles were mixed in different concentrations with soil in which biodegradation experiments were carried out under different conditions - i.e. with and without growing plant, with and without nitrogen fertilization. After 90 days, were soil analyzed. Thermogravimetry was used to determine the amount of residual non-degraded micro-bioplastics and to determine the effect of biodegradation on the properties of soil organic matter. Differential scanning calorimetry provided information on the effect of biodegradation on the evaporation enthalpy of adsorbed water from the soil, while the amount of water in the soil was also determined. Furthermore, the effect on field water holding capacity was determined and sieve analysis of individual samples was performed to characterize the effect of biodegradation on soil particle size distribution. Biodegradation conditions were shown to affect not only the rate of biodegradation but also some soil parameters. As expected, biodegradation of P3HB was proved to be faster in a nutrient-rich environment. In contrast, lack of nitrogen in soil with growing plant caused a decrease in the evaporation enthalpy of water and a reduction in the amount of water in soil, which can lead to easier soil drying and cause stress conditions for plant growth. Increased soil particle aggregation was observed in all sample series with P3HB compared to soils without P3HB addition.
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Biotechnological production of polyhydroxyalkanoates on wheat bran
Guziurová, Pavlína ; Pernicová, Iva (referee) ; Obruča, Stanislav (advisor)
The bachelor thesis deals with the biotechnological production of polyhydroxyalkanoates (PHA) from lignocellulosic waste – wheat bran. The aim was to determine whether the hydrolysate from wheat bran subjected to different types of pretreatment could be used as a substrate for the production of PHA using selected bacterial strains. The selected strains were Halomonas organivorans, Halomonas halophila and two strains of Schlegelella thermodepolymerans. Halophilic strains were proved as the best producers and were subsequently used for cultivations. The hydrolysates after neutral pretreatment were utilized by the bacteria most efficiently, due to the lowest content of microbial inhibitors (phenolic substances) where the bacteria produced the most PHA. The highest value of produced PHA was determined on the hydrolysate after neutral pretreatment by using the strain Halomonas organivorans, namely 2,82 g/l. The hydrolysate was also used for the production of lactic acid bacterial strains of Lactobacillus. The highest achieved concentration of produced lactic acid was 16,73 g/l by the Lactobacillus casei strain.
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Use of the organism Daphnia magna in a multigenerational ecotoxicity test
Klasová, Kristýna ; Maršálková, Eliška (referee) ; Zlámalová Gargošová, Helena (advisor)
This bachelor thesis deals with the multigenerational effect of microparticles of the biodegradable polymer polyhydroxybutyrate (P3HB) on the freshwater organism Daphnia magna. The presence of microplastics in the environment is a frequently discussed environmental problem, hence efforts are being made to develop biodegradable plastics that would degrade more easily in the environment. The most studied biopolymer P3HB, however, there is not much information on its ecotoxicity yet. In the context of this work, ecotoxicity was assessed using a multigeneration assay; in addition, the effect of P3HB microparticles was compared to that of naturally occurring particles. Multigeneration assays are not yet commonly used for ecotoxicological evaluation, but they offer a comprehensive and realistic view of the effect of the test substance on the test organisms. In this work, 4 generations of D. magna were exposed to P3HB microparticles and kaolin microparticles for comparison. The results showed no negative effect on the mortality of the organism, but a slight decrease in reproductive activity was observed.
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Preparation of skin masks with the anti-acne effect
Geierová, Kateřina ; Bendová, Agáta (referee) ; Márová, Ivana (advisor)
This bachelor thesis was focused on the preparation and characterization of nanofibers containing active agents with the aim of using these materials in anti-acne facial masks. The nanofibers were prepared from polyhydroxybutyrate solution and gelatin solution by electrospinning method. Among the active ingredients, eugenol and piperine were used to functionalize the nanofibers. In the theoretical part, the types of face masks, the individual active ingredients, the materials for the preparation of nanofibers, their preparation methods and their characterization were characterized. In the practical part, the antioxidant and antimicrobial activity of the active ingredients themselves was investigated. Subsequently, the release rate of selected active ingredients from the prepared nanofibers was monitored in three model environments. The antimicrobial activity of the nanofibers was monitored on three microorganisms, namely Staphylococcus epidermidis, Cutibacterium acnes and Escherichia coli.
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Influence of microbioplastics on aquatic plants
Mácová, Sabina ; Maršálková, Eliška (referee) ; Kučerík, Jiří (advisor)
Plastic pollution is becoming a serious environmental problem, for this reason, in recent years efforts have been made to propose alternatives to conventional plastics. Biodegradable plastics appeared to be a possible alternative due to similar properties to synthetic plastics and because they are considered safe and degradable in the environment. However, under real conditions, biodegradation is a relatively time-consuming process that can lead only to biofragmentation into small particles, co-called microbioplastics. So far, very little is known about their impact on the environment. This work deals with the ecotoxicological influence of biodegradable poly(3-hydroxybutyrate) (P3HB) microparticles in two size fractions (particles
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Preparation and characterization of nanoparticles with encapsulated antimicrobial component
Dohnalová, Marie ; Strečanská, Paulína (referee) ; Márová, Ivana (advisor)
This bachelor thesis is focused on the preparation and characterization of particles with encapsulated natural substances with antioxidant and antimicrobial properties. Selected antioxidants were anthocyanins, eugenol and vitamin E, as one of the most powerful antioxidants. At the same time, antimicrobial agents were chosen, in this case eugenol. In the theoretical part, individual active substances, materials for the preparation of particles, methods of their preparation were characterized and the principle of determining the safety of used materials. In the experimental part, selected active substances were characterized and the preparation of particles was optimized. Two types of liposomes were prepared, for which the encapsulation efficiency, size and stability were determined. Also prepared aqueous extracts of blueberries and blackberries were prepared, for which total anthocyanin content has been determined. The extracted substances from the plant material were encapsulated into alginate particles. Furthermore, the gradual release of active substances from particles into model environments using a spectrophotometer was determined. During the gradual release of active substances from the particles, the antioxidant effect was also monitored, in which it was possible to observe a decrease with the passage of time. The antimicrobial effect of active substances and liposomes against model microorganisms Escherichia coli and Micrococcus luteus was also tested. Cytotoxicity tests on human keratinocytes were performed on selected active substances, extracts and prepared nanoparticles, where it was proven that the selected materials are non-cytotoxic. Finally, a proposal for a possible application form in the form of an alginate hydrogel was created.
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Study on degradation processes of bioplastics
Fojt, Jakub ; Koutný, Marek (referee) ; Gregor, Tomáš (referee) ; Kučerík, Jiří (advisor)
Biodegradable bioplastics are currently developed as a more environmentally friendly replacement for conventional plastics to be used in agriculture or packaging materials. As the production of these products increases, so will the likelihood of introducing them in the environment. Biodegradable materials are expected to biodegrade rapidly, thereby they should reduce the number of microplastics in the environment. Biodegradability is currently determined by biodegradation tests, the parameters of which are defined in very general terms and often do not reflect the actual conditions under which the bioplastic will degrade in the environment. There is a lack of knowledge about the fate and impact of these particles in different ecosystems (especially in soil, where contamination is expected to be highest). Therefore, in this dissertation, we critically evaluate the ISO soil biodegradation test and extend it with a subsequent determination of bioplastic residues in soil. For this reason, an analytical method for the determination of polyhydroxybutyrate and polylactic acid microplastics based on methods used for the determination of conventional microplastics. The effect of microbioplastics on soil is also discussed, focusing on the effects that may pose problems in agriculture. The influence of microbioplastics on abiotic (soil water properties, soil structure) and biotic (soil diversity, nutrient cycling) soil properties immediately after their entry into the soil are described. The effect of biodegradation and long-term presence of microbioplastics in soil on soil organic matter, nutrient content, and soil microbial diversity (described by determining the activity of 5 key enzymes involved in carbon, nitrogen, and phosphorus cycling) are also studied. The last chapter demonstrates the potential problems that can be encountered when bioplastic products are applied in agriculture, where the growth of fungi and molds naturally occurring in the soil can be accelerated. As a result of this dissertation, a comprehensive view of bioplastics in the environment is presented, which can serve to assess the suitability of the application of current generation bioplastic products in agriculture and the possible management of bioplastic waste.
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METHODS OF POLY-3-HYDROXYBUTYRATE EXTRACTION AND THEIR OPTIMIZATION
Pospíšilová, Aneta ; Plachá,, Daniela (referee) ; Kowalczuk, Marek (referee) ; Přikryl, Radek (advisor)
Poly-3-hydroxybutyrát (PHB) je biolodegradovatelný a biokompatibilní termoplastický polymer se širokou škálou potenciálních aplikací. Výroba PHB typicky zahrnuje fermentaci obnovitelných surovin bakteriemi. Získávání PHB z bakterií je však často náročné a neefektivní. V této práci jsou zkoumány a porovnány různé metody pro získání PHB, včetně digesce, mechanického rozrušení a extrakce. Jsou diskutovány různé optimalizační strategie, které lze použít ke zlepšení účinnosti izolace PHB. Experimentální a výsledková část popisuje snahy o zlepšení metod izolace, zejména kyselé a mýdlové digesce, které byly vybrány jako potenciálně ekonomické, bezpečné a šetrné k životnímu prostředí. Společně s našimi průmyslovými partnery jsme tyto technologie úspěšně otestovali v čtvrtprovozním měřítku a plánuje se další vývoj. Řešily se také možné aplikace a komercializace PHB. Bylo zjištěno, že PHB může nahradit některé mikroplasty v kosmetice a že toto úsilí má potenciál, protože přítomnost mikroplastů v běžných výrobcích je stále vysoká a na úrovni Evropské unie je plánován jejich zákaz. Dále byla studována tepelná stabilita PHB v závislosti na metodě získávání a byly vyvinuty dvě stabilizační metody, které umožnily použít PHB získaný digescí za použití mýdla v materiálových aplikacích.
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Utilization of physico-chemical and spectroscopical methods in study on microbial extremofiles
Dobešová, Kateřina ; Enev, Vojtěch (referee) ; Sedláček, Petr (advisor)
The aim of this bachelor thesis is the determination od polyhydroxyalkanoates in the cells of extremophille bacterie, preformed by several methods. The chosen bacterium was Schlegelella thermodepolymerans DSM 15 344 Thermogravimetric analysis, infrared spectroscopy with Fourier transformation, and Raman spectroscopy were used in this thesis. The TGA method was used for the determination of extracellular and intracellular water in samples. The FTIR method was used in order to observe the amount od PHA, but aslo to observe the physical properties of the polymer in the sample, specifically to determine either amorphous or crystalline featuers of this polymer. Raman spectroscopy was used in oder to confirm the presence of PHA in the samples. All results e´were compared eith the results accomplished by gas chromatografy.
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Preparation and characterization of nanofiber wound dressings
Jiroušková, Pavla ; Uhlířová, Renata (referee) ; Skoumalová, Petra (advisor)
The presented bachelor thesis deals with the preparation and characterization of nanofiber wound dressings. The materials used for the preparation of nanofibers were poly(3-hydroxybutyrate) and gelatin. Active substances, such as ampicillin and ibuprofen, were incorporated into the wound dressings. In the theoretical part of the work skin, wound healing, and nanofibers and their properties were described. This part also deals with the use of nanofibers as wound dressings. Additionally, it depicts materials suitable for the preparation of nanofiber wound dressings. Furthermore, this section contains a review focused on various methods of preparation of nanofibers, drugs that can be incorporated into the fibers and the subsequent determination of the safety of the prepared dressings. In the experimental part, nanofiber wound dressings containing ampicillin and ibuprofen were produced. The maximum possible amount of active substance feasible to be incorporated into the nanofibers has been determined. Subsequently, combined wound dressings were prepared to study the release rate of active substances into the model environments. The release in the time intervals was determined spectrophotometrically. Finally, antimicrobial activity assays were performed to test the effect of dressings containing ampicillin on selected strains of microbiirganism: S. Epidermidis, E. Coli and M. Luteus
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