Isolation of PHA from bacterial biomass and their subsequent purification

This bachelor thesis deals with the isolation and characterization of the bacterial polymer PHA isolated from the bacterial strain Halomonas halophila (CCM 3662) by osmotic stress in distilled water, ie hypo shock, when the cells crack and release PHA. The addition of biosurfactants simultaneously solubilizes the proteins and lipids of the residual biomass, theoretically achieving a purer PHB product without the use of toxic substances such as chloroform. The theoretical part of the work focuses on PHA in terms of their general properties and use, the mechanism of synthesis of PHA microorganisms and their subsequent degradation and the existing strategy for isolating PHA from bacterial biomass. The experimental part describes the production of PHB bacteria Halomonas halophila and the subsequent process of isolation of PHB by hypo shock of halophilic bacteria in distilled water with the addition of selected biosurfactants. Biosurfactants used in the work are coconut soap, lecithin, rhamnolipids, sophorolipids, coco glucoside, lauryl glucoside and cocoamidopropyl betaine. The properties of the isolated PHB material were analyzed by gas chromatography with FID detection and SEC-MALS and FTIR methods. Based on the results, we chose the pair of coco glucoside and lauryl glucoside as the most suitable biosurfactants that can be used to isolate PHB from bacterial biomass. In combination with washing the material in ethanol, at concentration of biosurfactant 5 g/l and isolation in 70 ° C, it was possible to achieve a purity of 90 % of material using cocot glucoside and 89 % purity of material using lauryl glucoside