Modeling of Bacillus spores: Inactivation and Outgrowth

摘要

This research models and analyzes the thermochemical damage produced in Bacillus spores by short, high-temperature exposures as well the repair process within damaged Bacillus spores. Thermochemical damage in spores is significantly due to reaction with water, hydrolysis reactions. Applying heat to the spore causes absorbed and chemically bound water molecules become mobile within the spore. These mobile water molecules react by hydrolysis reactions to degrade DNA and enzyme molecules in the spore. In order to survive the thermal inactivation, the spore must repair the damaged DNA during spore germination. The DNA repair process, as well as other germination functions, is dependent on reactions catalyzed by enzymes that are viable after the thermal exposure. Increased damage to the enzymes during thermal inactivation, affects the rate at which the spore DNA is repaired. If the enzymes are damaged to such an extent that the DNA repair is not completed, the spore is unable to germinate, or produce outgrowth. The DNA repair process, repair enzymes, and outgrowth time influences the spore's chance of survival. Using this information, a probability of survival model was created based on water mobility, hydrolysis reactions, an initial state of DNA, viable repair enzymes, and an outgrowth time.