National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Biodegradability of bacterial natural and modified polyesters and their composites
Pala, Martin ; Babák, Libor (referee) ; Obruča, Stanislav (advisor)
Presented work was focused on biodegradability of bacterial natural and modified polyesters and their composites. The first part of the work was focused on study of influence of PHA granules structure on their biodegradability using selected enzymes and influence of physiological conditions on PHA stability. Overall, tested polymer either in crytalinne or amorphous phase seems to be rezistent to attack of seleced hydrolytic enzymes such as lipases or proteases and is stable in simulated physiological fluids as well. Because of thies results, it is possible to use tested PHA materials in biomedical applications requiring rather resistant biomaterials. Second part of the work was focused on microbial degradation of modified PHA materials considering their potential environmental impact. Both mixed thermophillic culture originaly used in wastewater treatment plant and bacterial strain Delftia acidovorans were employed for biodegradation tests. Composites containing chlorine PHB and PHB films modified using plasticizers were tested. Films containing chlorine PHB cause inhibition of biomass growth to both tested cultures. The highest rate of degradation (31%) was observed in presence of bacterial culture with film containing 10% chlorine PHB. The results show that used microbial population is important factor affecting biodegradability.
Production of proteolytic enzymes by selected microorganisms
Pala, Martin ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
Presented work was focused on study of microbial production of proteolytic enzymes used in many industrial applications. Bacterium Bacillus subtilis was used for laboratory production of microbial proteolytic enzymes. During cultivation production of biomass and proteolytic enzymes were studied influence of substrate type and stress factor application (osmotic shock, hydrogen peroxide and ethanol) was tested too. The highest concentration of biomass was measured in concentrated BM medium after 32 hours of cultivation. Biomass yield was 1.11 g/l. The highest protease activity (88.28 U/ml) was obtained in the same cultivation medium and time of cultivation. According to results of stress experiments it can be concluded that most of used stress factors exhibited a toxic effects to bacterial culture even at low concentrations.

See also: similar author names
1 Pala, Michal
1 Pala, Miroslav
1 Pala, Miroslav Christoph
3 Pála, Martin
2 Pála, Matěj
2 Pála, Milan
1 Pála, Miloslav
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