Abstract:
:The effects of pressurized CO2 on the survival of Escherichia coli and the mechanism of cell inactivation were studied. Bacterial cultures were inoculated in nutrient broth and incubated at 30 degrees C for 18 h. Exposure of the cells to CO2 under pressures ranging from 2.5 to 25 MPa and at temperatures between 8 and 40 degrees C was performed in a double-walled reactor with a 1 L capacity. The effect of the treatment on the cells was evaluated by plating and by transmission and scanning electron microscopy observation. Vapour CO2 generated a bacteriostatic effect. In liquid or supercritical state, CO2 provided a bactericidal effect. The bactericidal effect increased with pressure and temperature. The mechanism of cell inactivation by liquid CO2 involved two stages. First, cell stress caused by the CO2 penetration provoked cell wall collapse and cellular content precipitation. Second, the cell death caused by supercritical extraction of intracellular substances and cell envelope perforation resulted in leaking of intracellular constituents. In supercritical conditions, the cell inactivation process had one single phase: cellular death.
journal_name
Can J Microbioljournal_title
Canadian journal of microbiologyauthors
Oulé MK,Tano K,Bernier AM,Arul Jdoi
10.1139/w06-078subject
Has Abstractpub_date
2006-12-01 00:00:00pages
1208-17issue
12eissn
0008-4166issn
1480-3275pii
w06-078journal_volume
52pub_type
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