Impact of PHA accumulation on stress resistance of bacteria against disinfection agents

This bachelor thesis deals with the influence of acumulation of PHA balancing on the resistence of bacteria against desinfecting means. Two bacterial strains, PHA accumulation Cupriavidus necator H16 and its mutant strain insoluble PHA synthase Cupriavidus necator PHB-4 were used as model microorganisms. These bacteria were exposed to three different concentration of three desinfecting means (etanol, savo and ajatin). The viability of bacteria by the action of disinfectants was determined by the plate method and by the flow cytometry. The influence of desinfecting means against bacteria was examined by the broth dilution method which rested in measurement of absorbance over time. Agar diffusion method was the last one technique use. The results show that PHA production positively aids cell defence against desinfectants because bacterial strain Cupriavidus necator H16 is more resistant than its mutant strain Cupriavidus necator PHB-4. Of the free selected disinfectants, ajatin is the most effective