Mechanism of the inactivation of bacterial spores by reciprocal pressurization treatment

Abstract

Aims: The mechanism of the inactivation of Bacillus subtilis spores by reciprocal pressurization (RP) was unclear. Therefore, the mechanism was investigated. Methods and Results: To investigate the effects of RP and continuous pressurization (CP) treatments on the inactivation and injury of B. subtilis spores, spores were treated at 25, 35, 45 and 55°C under 200, 300 and 400 MPa. RP treatment was effective in injuring and inactivating spores. Scanning electron microscopy and transmission electron microscopy observation showed that spores treated by RP treatment were more morphologically and structurally changed than the ones treated by CP treatment. There were significant differences between the release of dipicolinic acid (pyridine-2,6-dicarboxylic acid) by RP and CP treatments. From this result, it was concluded that the core fraction was released into the spore suspension. Conclusions: The mechanism of RP treatment is believed to work as follows: hydrostatic pressure treatment initiated germination of bacterial spores, and the repeated rapid decompression caused disruption, injury and inactivation of the germinated spores. Significance and Impact of the Study: This study indicated that the physical injury of bacterial spores was effective to inactivate the bacterial spores through the disruption of spores and leakage of their contents.

Supercritical carbon dioxide and hydrogen peroxide cause mild changes in spore structures associated with high killing rate of Bacillus anthracis

“…Initiation of B. subtilis spores germination was achieved with static pressures between 200 and 400 MPa (Furukawa et al, 2003). It also has been shown that treatment with pressurized CO 2 helps induce spore germination, rendering the spores more susceptible to deactivation (Ballestra and Cuq, 1998).…”

Lethality of Shock Pressures to a Marine Vibrio sp. Isolated from a Ship's Ballast Water

“…Chemicals including pesticide should not be used for this purpose because they have been recognized as environmental pollutants. Application of critical CO, (Spilimbergo et al, 2003), hydrostatic pressures (Hauben et al, 1997;Furukawa et al, 2003), hydroxyl radicals (Bai et al, 2005), and shock pressures (Abe et al, 2005) seem to be available for use to kill the harmful marine microorganisms in ships' ballast water. l n this study, we examined the lethality of shock pressures to the Vibrio sp.…”

Effect of Repeated Pressure Treatment on Breakdown of Clumps of Bacterial Spores

“…We have indicated that repeated pressure treatment (repeated compression, pressurization and decompression) was effective to inactivate bacterial spores (Furukawa et al, 2000a;Furukawa et al, 2000b;Furukawa et al, 2003). Spores were more inactivated by RP treatment than by continuous pressure treatment (consisting of 1 cycle of 30 min pressurization; CP treatment).…”

“…Germinated spores were increasingly injured by the repeated decompression. In RP treatment, spores were first germinated and then were injured by repeated decompression (Furukawa et al, 2000a;Furukawa et al, 2000b;Furukawa et al, 2003).…”

“…In RP treatment, spores were first germinated and then were injured by repeated decompression (Furukawa et al, 2000a;Furukawa et al, 2000b;Furukawa et al, 2003). Here, only pressurization was needed to germinate the spores (Furukawa et al, 2000a).…”