Saccharomyces cerevisiae Morphology under Hyperbaric Gases
Integration of life sciences & engineering
Bio-transformation in the Laboratory and in Large Scale Production (T5-3)
Keywords: hyperbaric reactor, yeast, morphology, viability
The effects of hyperbaric stress on the morphology of Saccharomyces cerevisiae were studied in batch cultures under pressures between 0.1 MPa and 0.6 MPa and different gas compositions (air, oxygen, nitrogen or carbon dioxide), covering aerobic and anaerobic conditions. A method using automatic image analysis for classification of S. cerevisiae cells based on their morphology was applied to experimental data. Information on cell size distribution and bud formation throughout the cell cycle is reported. Cell viability was assessed through the Methylene Blue staining method and the percentages of viable and non-viable cells were also estimated using digital image processing.
The results show that the effect of pressure on cell activity strongly depends on the nature of the gas used for pressurization. While nitrogen and air to a maximum of 0.6 MPa of pressure were innocuous to yeast, oxygen and carbon dioxide pressure caused cell inactivation, which was confirmed by the reduction of bud cells with time. Moreover, a decrease in the average cell size was found for cells exposed for 7.5 h to 0.6 MPa CO2. A model taking into account cell viability reveals the opposing effects between oxygen availability and the baric and oxidative stresses present on the system. It is shown that cell viability in general is not constant during the experiments but strongly depends on the environment.
Presented Thursday 20, 16:20 to 16:40, in session Bio-transformation in the Laboratory and in Large Scale Production (T5-3).
