National Repository of Grey Literature 40 records found  beginprevious30 - 39next  jump to record: Search took 0.00 seconds. 
Production of polyhydroxyalkanoates from waste substrates and their isolation
Grossová, Marie ; Babák, Libor (referee) ; Márová, Ivana (advisor)
The aim of this work is to study the possibility of microbial production of polyhydroxyalkanoates (PHA). PHA can be used as biodegradable materials. Bacterial strain Cupriavidus necator was used for laboratory production of PHA. This bacterium was cultivated in medium with various precursors to produce copolymers of 3HB with 3HV or 4HB. Another part of the work was aimed at cultivation of C. necator on different waste substrates, especially oils, with the aim to achieve the highest production of polymer. Another large part of the thesis is dedicated to isolation strategies of PHA using enzymes. Commercially used proteases – alcalase and pancreatin – can be used with advantages for digestion of bacterial cells. A number of optimization experiments showed that application of proteases leads to enhancement of PHA purity to about 13%. Purity increase up to 90 % was achieved by adding a surfactant, which promotes the solubility of non-PHA forming polymer. This surfactant increases the purity of 20 % when compared to control. The last part of presented work deals with the use of enzyme solution isolated from Bacillus subtilis medium. Its application to C. necator culture led to the yield of polymer at a purity exceeding 95 %. These results could represent the basis for new isolation strategies, which can lead to more efficient yield of PHA.
Thermophilic Enzymes
Kuchtová, Ludmila ; Obruča, Stanislav (referee) ; Babák, Libor (advisor)
Thermophilic enzymes are produced by organisms living at temperatures between 60 and 80°C, in some cases even higher, and are active and stabile at these temperatures. This work deals with thermophilic and hyperthermophilic organisms, their habitats, ways of adaptation to environment with considerably higher temperatures than optimal temperature for most organisms, and recent findings and opinions about possible factors enhancing protein thermostability. Properties and behaviour of thermophilic enzymes and their current applications (i.e. PCR, starch industry) are summarized. Advantages and disadvantages of using of these enzymes in comparison to currently used mesophilic enzymes are compared. Possible applications of thermozymes in various industrial branches, where they could replace some environment polluting procedures, simplify technology and be economically important, are introduced.
Kinetics and temperature dependance of cellulose degrading enzymes in the Arctic soils
Kinetics and temperature dependance of ?-glucosidase and cellobiosidase was investigated in Arctic soil. These enzymes are key in cellulose degradation, while ?-glucosidase produces the final product of cellulose degradation, the glucose, which si readily available to soil microbes and can influence the CO2 production. The enzymes activities was measured using fluorogenic substrates.
Production of Enzymes by Fungal Colonies in Soils: A Laboratory Study
Šnajdr, Jaroslav ; Popelářová, Petra ; Baadri, S. ; Alawi, A. ; Boddy, L. ; Baldrian, Petr
Production of enzymes by fungal colonies in soils is affected by mycelium age and the presence or absence of interspecific mycelial interactions
Fungal community and enzyme activities in topsoil layers of Quercus petraea forest: how important is the seasonality?
Voříšková, Jana ; Valášková, Vendula ; Baldrian, Petr
The analysis of fungal community composition and enzyme activities in topsoil layers of a Quercus petraea forest show that seasonality is an important factor affecting community composition
Litter decomposition in a primary succession chronosequence on brown coal mine deposits
Urbanová, Michaela ; Valášková, Vendula ; Šnajdr, Jaroslav ; Baldrian, Petr
Litter decomposition in a primary succession chronosequence on brown coal mine deposits varies along with the successional age of the site
Degradation of lignin and humic substances in forest soil by saprotrophic basidiomycetes
Šnajdr, Jaroslav ; Steffen, K. T. ; Hofrichter, M. ; Baldrian, Petr
The work deals of degradation of lignin and humic substances in forest soil by saprotrophic basidiomycetes is significant, yet species-dependent

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