Examination of B. Subtilis Spore Sterilization by an Underwater-Ar-Plasma

Abstract

Advanced oxidation process (AOP) with hydroxyl radicals (OH) is considered to be useful for sterilization; therefore, we have proposed an underwater plasma source with a porous glass membrane which functioned in bubble supply and the formation of micro-discharges. In this study, we first examined whether B. subtilis spores could be sterilized by the underwater plasma of which operating gas was argon. Next, similar experiment was conducted by using mannitol, and the numbers of colonies were compared. The obtained results showed that OH radicals generated at gas-liquid interface were responsible for the sterilization.