The main objective of the Thesis is to understand the oxidation of must, especially enzymatic oxidation. It is caused by the oxidative enzymes that are already present on the grapes in vineyard, especially on those badly infected by mushroom diseases. The two main oxidative enzymes that need to be targeted are tyrosinase and laccase, collectively called polyphenoloxidasi (PPO). These most active oxidative enzymes, which already oxidize the must in the beginning of wine production and degrade the quality of future wine, belong to the group of oxidoreductases where oxygen is a catalyst for enzymatic activity and the phenolic compounds are substrates. Another main goal of the Thesis is to determine polyphenol oxidase activity on several samples of varieties and to compare how it affects other wine parameters such as acids, sugar content, etc. We will discus the oxidation of caftaric acid and its subsequent conversion to quinones. Quinones are just the product of the oxidation of phenolic compounds due to the activity of these enzymes. Caftaric and coutaric acids are the most oxidizable compounds for these enzymes and will therefore be discussed in more detail. It is also necessary to focus on possible protection against enzymatic oxidation.

A practical technique for enzymatic dissociation and isolation of pikeperch (Sander lucioperca) (Percidae, Teleostei) early stage germ cells (eGC), including spermatogonia and spermatocytes, is reported in this study. Their potential to differentiate into functional gametes, and transmit genetic information to the next generations makes them suitable for cryopreservation and surrogate reproduction studies by germline chimera. Two different age groups (14 month old and 18 month old) of pikeperch were used to adjust the correct stage of eGC isolation. Finally the 18 month old samples were selected due to their high average gonadal volume (0.513 g). 10 ml PBS + 0.3% trypsin (304 mOsm/kg, pH 8) were used for enzymatic dissociation of testicular cells and they were sorted by centrifugation in Percoll density gradient. eGCs were identified on the basis of their ploidy level by CYSTAIN DNA 1 steps kit (PARTEC) and morphological characteristics trough by light microscopy. Cell counting was performed on histological sections and Percoll gradient layers whit the method of random square counting. The method of isolation enriched the number of eGC from 41.3% to 84.7%, obtained from the 33% of Percoll concentration.

Accumulation of sediments in fishponds is a serious problem for today's aquaculture. High economical, organizational and time-consuming requirements are often the limit factor for many fish farmers. One of the available solutions has recently emerged bacterial-enzymatic mixtures, which thanks to modified bacteria cultures, have been able to reduce organic matter from sediment and improve overall physical and chemical water parameters. The aim of this diploma thesis was to verify the effect of the bacterial - enzymatic mixture PTP plus in laboratory and field conditions. For the laboratory experiment, was chosen a method with different concentrations of the PTP plus, under the controlled conditions of the glass containers. However, the results of the laboratory test did not confirmed significant effect of this bioenzymatic mixture on the reduction of the organic component of the sediment nor on the changes in the physical and chemical parameters of the water. But the influence at the visual properties of the water was confirmed in container with several times higher dose. Three small ponds near Bohuslavice near Konice, with a total area of approximately 2.5 hectares were chosen for the field experiment. The results of the field experiment also did not confirm the significant effect of the bio-enzymatic blend on the physical and chemical parameters of the water in the monitored localities. However, in the lowest location of the fishpond cascade, BOH I, was recorded slight reduction of sediment organic component.

The thesis describes the development and survival of immature Ips typographus specimens at low temperatures under laboratory and field conditions. Further, the focus was identifying and characterizing the digestive enzymes present in the gut of adult I. typographus, their location in the gut and enzymatic fluctuation over a full calendar year, with a specific focus on digestion of cellulose.

Presented thesis is focused on microbial activity of forest soils and aims at characterizing some of its parameters on sites with different silvicultural management practices. Coppice, coppice-with-standard and high forest stands were compared in terms of carbon and nitrogen content, content of microbial biomass, enzymatic activity and selected physical properties of soil. Study was conducted between September 2015 and April 2016 on pre-existing TARMAG II research plot near Soběšice, Brno, Czech Republic. Samples were collected during three different calendar seasons, allowing for seasonal dynamicity assessment of the studied parameters. Statistical evaluation detected significant effect of management type on potential respiration of studied soil samples as well as significant effect of seasonality on microbial biomass content in incubated samples, phosphatase activity in fresh soil samples, catalase activity in both fresh and incubated samples and potential respiration of studied samples. Results also show that the overall potential activity of urease and catalase was at its highest during the winter season.

Major part of ethanol production for industrial use in Czech Republic is made from cereals. Effect of acid, alkali and enzymatic hydrolysis after thermopressure preparation takes part in the paper. The most promising alternative is enzymatic hydrolysis. Especially efficiency of different hydrolytic enzymes towards different species of cereals takes the main part of the simulations. Local farm products, oats, barley and wheat were prepaired by steam explosion in different pressure. After hydrolysis were detected the GE and after fermentation was observed the production of alcohol.

The main goal of this thesis was to evaluate the influence of additives on the qualitative indicators of grass silage. The evaluation concentrated in particular on lactic acid, pH and the degree of proteolysis. The selected qualitative indicators were monitored in 36 samples of grass silage from the region of South Bohemia. Silage samples were divided into three groups. The first group was a guide sample without any additives. The second group was treated with bacterial additives and the third group with bacteria-enzyme additives. Classification of silage samples was done according to "Norma 2004". Each sample was evaluated in terms of quality of fermentation and the content of nutrients. Statistically significant differences (p <0.05) were found in the content of lactic acid, pH and the degree of proteolysis between the group of silages without additives and the group treated with silage additives.

In diploma thesis the process of enzymatic hydrolysis of waste paper as a source for the production of liquid biofuels is discused. It follows directly the homonymous diploma thesis from Ing. Brummer, and it is based on the findings, which were solved and decided in previous work. In the theoretical part there is a summarization of basic information on the enzymatic hydrolysis of waste paper and the associated influences of various factors of the rate and degree of hydrolysis. Higher attention is paid to a waste cardboard and its pretreatment methods due to the maximalization of the yield of hydrolysis. The next part summarizes options of the fermentative production of biofuels, focusing on the method of simultaneous saccharification and fermentation, where the further appropriate organism for ethanol fermentation is discussed. The last part is about the technological process from the raw material input to the separation of ethanol. In the experimental section the pre-treatment of waste paper in order to maximize the efficiency of hydrolysis was examined. The best results were achieved using a vibratory mill. In addition, various parameters for simultaneous saccharification and fermentation were optimized using enzymes from Novozymes® company and the yeast Saccharomyces cerevisiae. The conversion rate of waste paper cellulose to reducing sugars was observed by spectrophotometric method by Somogyi - Nelson and the amount of produced ethanol was quantified using HPLC / RI. As a part of this thesis some conditions (amount of enzyme, substrate, nutrients, yeasts, temperature, pH, type of buffer) were optimized to maximize the effectiveness of the overall process. All experiments were carried out on corrugated cardboard, which was chosen as the most promising material for hydrolysis that was among the waste paper pulp in diploma thesis by Ing. Brummer.

In the diploma thesis are discussed the process of enzymatic hydrolysis of waste paper as a source for the production of bioethanol by bacteria Zymomonas mobilis. In the theoretical part summarize basic information about particular methods of hydrolysis, about paper used as a raw material for enzymatic hydrolysis, about possibilities of the fermentative production of bioethanol focusing on the method of simultaneous saccharification and fermentation comparison with enzymatic hydrolysis and fermentation. Suitable microorganisms for ethanolic fermentation and simultaneous saccharification and fermentation and their advantages and disadvantages, are further discussed in this part as well. The theoretical part ends with the suggestion of the technological process for production of bioetanol. It covers all necessary steps from the input of raw material to the separation of produced ethanol. In the experimental part various parameters of hydrolysis, fermentation and simultaneous saccharification and fermentation were optimized using enzymes from Novozymes® company and the Zymomonas mobilis CCM2770 and Zymomonas mobilis LMG457 bacterium. The conversion rate of paper cellulose to gluckose and production of ethanol were observed by HPLC/RI method. Type of buffer, quantity of cells, enzyme and substrate were optimized in order to maximize the efficiency of the process. All experiments were performed on paper containing high amount of cellulose and for comparison on standard medium which contains gluckose. The highest yields was achieved with the use of Novozymes® Cellulosic ethanol enzyme Kit. The strain Zymomonas mobilis LMG457 has demonstrated as a better producer.

The paper analyzes the factors affecting the quality and nutritive value of wilted grasssilage. Grass silage sample were collected in the operating conditions for the firstmowing. Three groups were formed after 12 samples. The first group was the controlwithout using preservatives. The sekond group were included in the silage treated withbacterial agents. The third group included the bacterial-enzymetreated silage additives. There were no statistically signifiant differences in lactic acid kontent (P < 0.05) andvalues of thedegree of proteolysis (P < 0.05) between the kontrol group without the useof silage additives and the group, which was used for bacterial and bacterial-enzyme additives.