Sterilizing Bacillus pumilus spores using supercritical carbon dioxide

Area of Science:

• Microbiology
• Chemical Engineering
• Sterilization Technologies

Background:

• Sterilization is critical for medical devices and pharmaceuticals.
• Supercritical carbon dioxide (SC CO(2)) offers a potential alternative to traditional sterilization methods.
• Evaluating SC CO(2) with additives for microbial inactivation is an area of research.

Purpose of the Study:

• To assess the efficacy of supercritical carbon dioxide (SC CO(2)) as a sterilization agent.
• To determine the impact of additives on the killing of Bacillus pumilus spores using SC CO(2).

Main Methods:

• Bacterial spores (Bacillus pumilus) were exposed to SC CO(2) under specific temperature and pressure conditions.
• Trace levels of additives including hydrogen peroxide, water, ethanol, and isopropanol were introduced into the SC CO(2).
• Spore log reduction was measured to evaluate sterilization effectiveness.

Main Results:

• Complete killing of Bacillus pumilus spores was achieved using 200 ppm hydrogen peroxide in SC CO(2) at 60°C and 27.5 MPa.
• Addition of water to SC CO(2) resulted in a greater than three-log reduction but was insufficient for sterilization.
• Ethanol and isopropanol additives did not enhance the killing efficacy of SC CO(2).

Conclusions:

• Supercritical carbon dioxide combined with hydrogen peroxide is a viable sterilization method.
• SC CO(2) with hydrogen peroxide offers a promising approach for sterilizing heat-sensitive materials.
• Further research may explore optimization of SC CO(2) sterilization parameters and additives.