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Bacteriocidal effect of Ag-containing superparamagnetic nanoparticles on selected bacteria
Čavojská, Miriam ; Šálek, Petr (referee) ; Trachtová, Štěpánka (advisor)
The aim of this work is to demonstrate the bacteriocidal effect of Ag-containing superparamagnetic nanoparticles on selected non-pathogenic bacteria. The theoretical part is focused on the characterization of superparamagnetism, but the main part of the work is the characterization of silver-containing nanoparticles, methods of their synthesis and their practical application. Furthermore, basic specificities for selected bacteria are presented. The experimental part is mainly focused on the cultivation of bacterial cultures together with nanoparticles, thus demonstrating the antibacterial effect of nanoparticles. The biocompatibility of the nanoparticles was also determined by real-time PCR using the corresponding DNA.
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The potencial of next-generation probiotics
Kharkevich, Viktoryia ; Langová, Denisa (referee) ; Trachtová, Štěpánka (advisor)
The aim of the bachelor thesis was to examine the possibilities of identifying probiotic microorganisms using molecular diagnostic techniques such as PCR and HRM-PCR in a commercially available product – Probiolact Forte 12. In the theoretical part, a literature review focused on next-generation probiotics was conducted. In the practical part, cultivation of microorganisms contained in one capsule in liquid medium and solid media was performed. DNA isolation was carried out using the NucleoSpin Microbial DNA commercial kit according to the manufacturer's instructions. The purity and concentration of isolated DNA were verified using spectrophotometric analysis. Primers for specific PCR analysis of DNA domains Bacteria and individual genera and species, whose presence the manufacturer declares in the preparation, were used for DNA identification. The results of the PCR analysis confirmed the presence of the target DNA, i.e., bacterial genera and species in the preparation, as claimed by the manufacturer.
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Microbiome of smear ripened cheese and its changes in dependence on the stages of production
Jandová, Karolína ; Mikešová,, Martina (referee) ; Trachtová, Štěpánka (advisor)
The theoretical part describes soft smeared cheeses, then deals with the technology of manufacturing said cheese with importance on the development of microbiome and describes the most commonly wanted microorganisms and contaminants. Shortly also deals with legislation requirements on the microbial quality of these chesses. The experimental part studies the development of microbiome and contamination by fungi of soft smeared cheese. Firstly, samples were collected in manufacture from each step of manufacturing. In the first part, microbial and microscopical assessment was done. In the second part, DNA was isolated from samples by a commercial kit and phenol-chloroform extraction. The concentration and purity of isolates were determined by spectrophotometry. By qPCR of the DNA isolates the main microbiome and contamination by fungi were examined. As part of the microbial and microscopical assessment, the expected bacteria were determined, and several species of yeast were found, instead of the expected one. Mold contamination was also found. Using molecular diagnostic techniques, the presence of bacteria, yeasts, fungi and the genera Brevibacterium and Candida was proved.
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Study of stability of antimicrobial nanomaterials in different environment by HPLC
Janderová, Šárka ; Trachtová, Štěpánka (referee) ; Márová, Ivana (advisor)
This thesis deals with the preparation of nanomaterials (nanoparticles, nanofibers) with encapsulated active substances and the stability of these nanomaterials in different environments using liquid chromatography. The development and optimization of methods for monitoring the kinetics of release of encapsulated substances from nanomaterials into various environments play a key role in research aimed at their utilization in the pharmaceutical, food, and cosmetic industries, and also contribute to the development of new antimicrobial nanomaterials limiting antibiotic resistance. The theoretical part focuses on the characterization of nanomaterials (nanoparticles, liposomes, nanofibers, and combined nanomaterials). Another section of the literature review deals with natural (eugenol, carvacrol, curcumin, thymol, vitamin E) and synthetic (ampicillin, streptomycin) antimicrobial substances. The final chapter discusses the instrumental methods used for the characterization of nanomaterials and the evaluation of their stability, released, and degradation products. In the practical part, the antioxidant activity of selected substances was first monitored. Liposomes were prepared, and their stability and encapsulation efficiency were examined. An HPLC method for determining active substances was optimized. Subsequently, the gradual release of the mentioned active substances from prepared liposomes was monitored. Nanofibers were prepared using forcespinning, and their release into selected model environments was also analyzed. Distilled water with minimal ion and impurity content served as a model environment, as well as a physiological solution at 25°C, simulating the temperature of the human body surface, and a physiological solution at 37°C, characteristic of human body temperature. This analysis provides a comprehensive view of the behavior of prepared materials and their potential practical applications. In the final section, combined nanomaterials (based on nanofibers and nanoparticles) with encapsulated active substances were prepared. The gradual release of active substances and any potential synergistic effects were examined for these nanomaterials.
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Preparation of Cosmetic Product Based on Microbial Extracts
Reichertová, Klára ; Trachtová, Štěpánka (referee) ; Hudečková, Helena (advisor)
This thesis is focused on the preparation of a cosmetic product based on microbial extracts. The thesis is divided into two main parts, theoretical and practical. The theoretical part describes the types of cultured microorganisms, microbial metabolites, legislation and safety of cosmetic products, composition of human skin and last but not least the applied analyses. The experimental part deals with the use of waste products of the food industry, specifically coffee grounds as a substrate for culture media. Furthermore, the cultivation is studied with a focus on the gain of metabolites useful in the cosmetic industry, the analysis of these metabolites by GC/FID and HPLC/PDA. The work addresses the preparation of microbial extracts, their testing including determination of polyphenol and flavonoid content and characterization of antioxidant activity and antimicrobial activity tested on bacterial cultures of Esterichia coli and Staphylococus epidermidis. The application of the analysed extracts and their application to the final product is also addressed. The last chapter discussed in this thesis to test the final product using Visioscope PC–35, instrument and performing sensory analysis. The cultured strains were Phaffia rhodozyma CCY 77-1-1, Cystophilobasidium macerans CCY 10-1-2, Rhodosporidium toruloides CCY 062-002-004 Chlorella vulgaris CCALA 924. The biomass obtained by cocultivation of Phaffia rhodozyma CCY 77-1-1 and Chlorella vulgaris CCALA 924 as well as the biomass of these two microorganisms cultured separately were used for the preparation of microbial extracts.
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Determination of selected bioactive substances in grapes
Havlíková, Markéta ; Trachtová, Štěpánka (referee) ; Vítová, Eva (advisor)
The subject of this thesis was the determination of selected bioactive substances in grapes and the subsequent comparison of differences between the samples. Two fractions of grapes (skins and pulp with seeds) of 4 grape varieties - Hibernal, Johanniter, Riesling and Aurelius - were analysed. Two methods were used for the determination: for phenolic substances, high-performance liquid chromatography with mass spectrometry and for volatile substances, headspace solid-phase microextraction coupled with gas chromatography and mass spectrometry. For each of these methods, the optimal extraction technique was first selected and then used for the analysis of all samples. The linearity of the external standard method was also verified with a reliability coefficient R2 in the range of 0.9650-0.9989 for high-performance liquid chromatography with mass spectrometry and 0.8571-0.9999 for headspace solid-phase microextraction coupled with gas chromatography and mass spectrometry. 63 volatile and 9 phenolic compounds were identified in the samples. From these, specific compounds of grapes (20 volatile compounds and 5 phenolic compounds) were selected. On the basis of the amount of observed compounds, the two grape fractions and subsequently the grape varieties were compared with each other. There were differences in the content of selected compounds between grape fractions and across varieties, which could probably be due to the geographical origin of the samples.
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The characterisation of selected type of „bio“ dairy product
Hanychová, Silvie ; Trachtová, Štěpánka (referee) ; Vítová, Eva (advisor)
This bachelor thesis deals with the sensory evaluation of kefir. Specifically the differences in the sensory properties of kefir produced using the same method from various types of milk were observed. The theoretical part was focused on kefir, its characteristics, composition and production using kefir grains. The experimental part deals with the comparison of four kefir samples based on sensory evaluation. The evaluation was made by the students from Faculty of Chemistry BUT, the untrained assessors. Therefore the evaluation results may be closely reflecting the opinions of common consumers. The samples of kefir were subjected to sensory evaluation by the ranking test and the pleasantness of chosen properties (appearance, colour, texture, odour and taste) was evaluated using a seven-point scale, as well as the overal acceptability of samples. The results were statistically processed and graphically evaluated.
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Non-traditional foods containing probiotic bacteria
Sobotková, Markéta ; Konečná, Jana (referee) ; Trachtová, Štěpánka (advisor)
Probiotic microorganisms are contained in common dairy products as well in unconventional probiotic products consumed especially in Asian countries. In the thesis is shown overview of chosen less common foodstuffs containing probiotic microorganisms, which no belong to fermented dairy products. In the thesis are discussed positive health benefits of probiotics foodstuffs on the host. The experimental part deals with the identification of probiotic microorganisms, which are contained in chosen probiotic product from Asia. DNA was isolated from the product by use phenol extraction and using magnetic particles. Probiotic microorganisms in chosen product were detected using method real-time polymerase chain reaction (qPCR).
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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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