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Production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) employing selected members of the genus Aeromonas
Čeparová, Klára ; Slaninová, Eva (referee) ; Obruča, Stanislav (advisor)
This bachelor thesis deals with the study of polyhydroxyalkanoates (PHA) production by Aeromonas spp. Four bacterial strains were selected for this study: Aeromonas aquatica (DSM 100827), Aeromonas bivalvium (DSM 19111), Aeromonas hydrophila (CCM 7770) and Aeromonas cavernicola (CCM 7641). The presence of phaC gene responsible for PHA synthesis was verified by polymerase chain reaction (PCR). In three of four selected strains (A. aquatica, A. bivalvium, A. hydrophila) the presence of phaC gene was confirmed. Strains A. cavernicola did not contain the phaC gene. PHA synthesis on different carbon substrates was further tested on strains with confirmed presence of the phaC gene. The aim of the thesis was to optimize the cultivation conditions of bacterial cultures for the PHA synthesis. The production of polyhydroxybutyrate (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx) was monitored. The evaluation of polymer presence and concentration in biomass was determined by gas chromatography. For cultivation, decanoic acid, caproic acid, octanoid acid, glukose, sucrose, fructose were used as carbonaceous substrates. The highest of both PHB and the copolymer P(3HB-co-3HHx) were recorded by A. aquatica with addition of decanoid acid at a concentration of 1 g/l to the production medium. Among the sugar substrates, cultivation on sucrose was the most successful with, resulting in the highest biomass concentration.
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