Proposed doctoral thesis deals with microbial production of biopolymers (polysaccharides and polyesters) using renewableble inexpensive resources as carbon and nitrogen source. At first, production of extracellular metabolites, mainly pullulan and poly-L-malic acid, by polymorphic microorganism Aureobasisium pullulans was studied. Further part of thesis was focused on production of bacterial biopolyesters polyhydroxyalkanoates (PHA). PHA are produced in the form of intracellular granules by various bacteria species. During the study of PHA production, sythesis of poly(3-hydroxybutyrate) and technologically significant copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) was investigated as well with regard to waste substrate utilization in biorafinery concept. Spent coffee ground seemed to be applicable waste in biorefinery proces. One of the coffee wastes used for PHA production was spent coffee ground hydrolysate which was converted to PHA by Burkholderia cepacia. Moreover, copolymer of 3HB and 3HV was accumulated when SCGH was used as a sole carbon source, no precursor had to be added. Another coffee waste, which was utillized by Cupriavidus necator H16, is represented by oil extracted from spent coffee grounds. Hydrolysis proces of waste substrates had to be optimized, to reach the highest possible saccharide concentration. Due to the hydrolysis process several toxic compounds can be formed, hence, influence of hydrolysis procesings on polyphenols content in hydrolysates was monitored. Waste substrates were also tested as potentional complex nitrogen source for PHA production. Hydrolysates of cheese whey and chicken feather were used as inexpensive complex nitrogen source for PHA production by C. necator, when waste frying oil was used as a carbon substrate. The finnal part of the thesis is dealing with possibilities how the PHA can be processed into atractive aplication forms. Liposomes with partial content of PHB had been prepared, moreover, for improving of antioxidant activity and antimicrobial effect the waste coffee oil was added. Micro-fibrous PHB materials were prepared for the purposes of water filtration. Higher filtration effectivity was observed when composite PHB fibrous material containing active charcoal or metal oxides was used. Important part of thesis is represented by study of degradation processes of prepared PHA-based aplication forms. Various microorganisms were tested on PHA depolymerases production. Biodegradability of PHA materials was tested in of composting conditions by standard composting test IS/ISO 20200. Changes in mechanical properties of polyurethan, where polyol was partialy replaced by PHB, were tested depending on the exposure of composting condition.
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:295714 |
| Date | January 2017 |
| Creators | Benešová, Pavla |
| Contributors | Pekař, Miloslav, Čertík, Milan, Márová, Ivana |
| Publisher | Vysoké učení technické v Brně. Fakulta chemická |
| Source Sets | Czech ETDs |
| Language | Czech |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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