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Transport of metal ions in humic hydrogels
Hegr, Martin ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This diploma thesis is focused on the study of diffusion of metal ions in hydrogel of humic acid. The objective of this thesis was to investigate the effect of the concentration of metal ions supply source and duration of diffusion on transport through the gel using method of diffusion couple. Cupric, nickel and cobalt ions were esed like the diffusion medium. All these ions were selected thanks to their high affinity for the humic acids and because they are ideal to investigate the diffusion through the humic gel. Chloride salts of these metals, namely CuCl2, NiCl2 and CoCl2, were used like supply sources. Three different concentrations of each solution were compared, specifically 0,05M, 0,1M and 1M, and also were three different durations of diffusion, specifically 10 hours, 1 day and 3 days. Metal ions were compared with each other in order to determine which one has the best transport properties through the humic hydrogel. The data, necessary for calculation, were obtained by UV-VIS spectrophotometry. Diffusion coefficients and duffusive flux of individual metal ions were determined from measured data.
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Enzymes of Candida tropicalis yeast biodegrading phenol
Koubková, Zuzana ; Stiborová, Marie (advisor) ; Turek, Michal (referee)
Effluents of industrial wastewaters from oil refineries, paper mills, dyes, ceramic factories, resins, textiles and plastic contain high concentrations of aromatic compounds, which are toxic to organisms. Degradation of these compounds to tolerant limits before releasing them into the environment is an urgent requirement. Candida tropicalis yeast is an important representative of eucaryotic microorganisms that are able to utilize phenol. During the first phase of phenol biodegradation, cytoplasmatic NADPH-dependent phenol hydroxylase of C. tropicatis oxidizes phenol to catechol. Catechol is in the second phase of biodegradative process oxidized to cis,cis-muconic acid by the reaction catalyzed with catechol-1,2-dioxygenase. In this diploma thesis we investigated the effect of the heavy metal ions on NADPH-dependent phenol hydroxylase and catechol-1,2-dioxygenase of C. tropicalis. Phenol hydroxylase was inhibited by Cu2+ and Pb2+ ions. Catechol dioxygenase was inhibited by all substances containing heavy metal ions (Fe2+ , Mn2+ , Cd2+ , Cu2+ and Pb2+ ), which were tested in this work. The most effective inhibition was produced by Pb2+ followed by Mn2+ , Cd2+ Fe2+ and Cu2+ ions. The higher sensitivity of catechol-1,2-dioxygenase to heavy metal ions might follow from the presence of histidine residue...
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Transport of metal ions in humic hydrogels
Hegr, Martin ; Smilek, Jiří (referee) ; Klučáková, Martina (advisor)
This diploma thesis is focused on the study of diffusion of metal ions in hydrogel of humic acid. The objective of this thesis was to investigate the effect of the concentration of metal ions supply source and duration of diffusion on transport through the gel using method of diffusion couple. Cupric, nickel and cobalt ions were esed like the diffusion medium. All these ions were selected thanks to their high affinity for the humic acids and because they are ideal to investigate the diffusion through the humic gel. Chloride salts of these metals, namely CuCl2, NiCl2 and CoCl2, were used like supply sources. Three different concentrations of each solution were compared, specifically 0,05M, 0,1M and 1M, and also were three different durations of diffusion, specifically 10 hours, 1 day and 3 days. Metal ions were compared with each other in order to determine which one has the best transport properties through the humic hydrogel. The data, necessary for calculation, were obtained by UV-VIS spectrophotometry. Diffusion coefficients and duffusive flux of individual metal ions were determined from measured data.
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Enzymes of Candida tropicalis yeast biodegrading phenol
Koubková, Zuzana ; Stiborová, Marie (advisor) ; Turek, Michal (referee)
Effluents of industrial wastewaters from oil refineries, paper mills, dyes, ceramic factories, resins, textiles and plastic contain high concentrations of aromatic compounds, which are toxic to organisms. Degradation of these compounds to tolerant limits before releasing them into the environment is an urgent requirement. Candida tropicalis yeast is an important representative of eucaryotic microorganisms that are able to utilize phenol. During the first phase of phenol biodegradation, cytoplasmatic NADPH-dependent phenol hydroxylase of C. tropicatis oxidizes phenol to catechol. Catechol is in the second phase of biodegradative process oxidized to cis,cis-muconic acid by the reaction catalyzed with catechol-1,2-dioxygenase. In this diploma thesis we investigated the effect of the heavy metal ions on NADPH-dependent phenol hydroxylase and catechol-1,2-dioxygenase of C. tropicalis. Phenol hydroxylase was inhibited by Cu2+ and Pb2+ ions. Catechol dioxygenase was inhibited by all substances containing heavy metal ions (Fe2+ , Mn2+ , Cd2+ , Cu2+ and Pb2+ ), which were tested in this work. The most effective inhibition was produced by Pb2+ followed by Mn2+ , Cd2+ Fe2+ and Cu2+ ions. The higher sensitivity of catechol-1,2-dioxygenase to heavy metal ions might follow from the presence of histidine residue...
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