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The aim of this thesis was the synthesis of carbon nanomaterials and their composites for environmental applications, application as an antibacterial agent, and crop protection. As the basic constituent of all prepared nanomaterials, graphene oxide (GO) prepared by the modified Hummers method was successfully used. In order to improve the desired properties, the prepared GO was further reduced and modified with magnetic nanoparticles (MPs) and nanoparticles (NPs) of metals or metalloids to form composites. In the prepared nanocomposites, the synergistic effect of graphene oxide and nanoparticles was utilized. In the case of nanocomposite formed from reduced graphene oxide (rGO) and MPs, this composite was used to bind Se (IV) as a heavy metal from an aqueous medium. In addition, the advantage of this material was its reusability after a recovery in ethanol. To protect agricultural crops against Xanthomonas euvesicatoria (X. euvesicatoria), which causes the bacterial spot disease of tomato and pepper and considerable economic casualties, nanocomposite containing GO and copper and silver NPs was used. This nanocomposite was selected for application to tomato and pepper plants after previous microbiological tests in vitro.

Bacteria are exposed to evolutionary pressure to an extent unlike other organisms. This leads to a high degree of adaptation to its surrounding. This thesis investigates the degree of adaptation towards higher accuracy in the transcription of DNA to RNA in coding sequences in the DNA of the E. coli bacteria. Two coding sequences with different nucleotide contents were investigated. Goodness-of-fit tests were performed but no significant adaptation towards higher transcription accuracy was found in the investigated sequences.

The aim of this thesis was to study the microbiological quality of different types of pâtés supplied by a Czech manufacturer. We investigated the occurrence and changes in selected microorganisms during the storage process. In all cases, we aimed to measure the total plate count, total number of psychrotrophic microorganisms, mold and yeasts and enterococci, as well as Enterobacteriaceae and Escherichia coli bacteria. Part of the samples was also examined for the effects of storage temperature (5 and 8 ° C) on the microbiological quality of pâtés. No statistical significance between microbial quality of the products stored at 5 and at 8 ° C was proved. The worst microbiological quality was discovered in the samples of course pâtés, where high levels of Enterobacteriaceae as well as traces of total plate count, psychrotrophic microorganisms, mold and yeasts were detected. In order to achieve a high microbiological quality of pâtés (as well as other meat products), the use of high quality raw materials and strict compliance with approved manufacturing processes is absolutely essential, as is sufficient hygiene during the production and distribution as well as in the course of the actual sale.

Malolactic fermentation (MLF), or malolactic fermentation is a process which converts Malic acid to lactic acid. Made with lactic fermentation bacteria. There are different kinds of lactic acid bacteria -- positive (Oenococcus oeni) and negative (Lactobacillus, Pediococcus). Malolactic fermentation on wine by reducing acidity, improves the stability of microbial and sensory properties of wine. Malolactic fermentation we can perform before the alcoholic fermentation, during alcoholic fermentation and alcoholic fermentation. It always depends on the situation and the type of wine. The aim of the practical part of the thesis was to track the progress of malolactic fermentation in white, pink and red wine. Malolactic fermentation was observed for two strains of bacteria -- commercial tribe and citrátnegative tribe.

This thesis deals with the influence of malolactic fermentation on analytical and sensory characteristics of white wines. Literary section addicts oneself to population growth lactic acid bacteria and factors affecting their development in wine, the metabolism of lactic acid bacteria and their products and how these products influence organoleptic properties of white wines. The practical part deals on the experiment of the inoculation of two different species of lactic acid bacteria in wines at different stages of vinification and on the analytical and sensory evaluation of produced wine.

Bacterial infections with complicated process and therefore lengthy, often unsolvable treatment due to emerging resistance to antibiotic drugs are currently increasingly frequent problem of many medical fields. The presented thesis entitled "Effect of heavy metal ions on the biological properties, resistance and virulence" was primarily focused on the study of selected metal ions (Ag +, Cd2+, Cu2+, Pb2+ and Zn2+) on the biochemical properties of bacterial strains, in particular observing their influence on free radical formation, creation of oxidative stress and growth properties. Detection of the influence of metals not only on biochemical parameters, but mainly their significant antimicrobial effect directed our further studies to testing of antimicrobial activity of metals (usually silver) or metal nanoparticles synthesized in complexes with polymer substances (chitosan, hyaluronic acid). The obtained results clearly showed the nanoparticles as the best form, so the effects of proven antimicrobial silver nanoparticles were subsequently compared with metalloid selenium nanoparticles, which even surpassed the previous results of antimicrobial activity. Finally, the effect of long-term action of metal ions on the emerging resistance or so-called multiresistance in the case of cross-resistance of metals and antibiotic drugs was tested.

This master's thesis is specifically concerned with the influence of malolactic fermentation on the aromatic profile of red wine. The literary (theoretical) part defines the malolactic fermentation and describes the volatile substances formed during malolactic fermentation. The practical part results from an experiment of various kinds of malolactic fermentation, where there are used two different strains of lactic acid bacteria. The experiment was carried out on three different varieties of wines which were sensorically and analytically evaluated.