Microrheological monitoring of life cycle of yeast cell Saccharomyces Cerevisiae

Bacterial adhesion and proliferation through biofilm is a major concern in industrial applications where surfaces are in contact with aqueous fluids. Bacteria in these environments are capable of rapid attachment and community development on those surfaces. NDT can play an important role thanks to its capability to monitor bio-physical properties. In this study, a simple technique to monitor the rheological properties of S. Cerevisiae growth at microscopic scale is proposed. This technique uses shear waves generated by an AT-cut quartz crystal at 5 MHz. In order to optimize growing conditions, the temperature, pH and substrate on which the yeast grows are tightly controlled. This grow is performed under aerobic conditions. Using a suitable model including the electrical properties evolution during S. Cerevisiae cultivation, the rheological properties elastic and viscous moduli (respectively G\´ and G") can be accurately extracted. Thanks to the high sensitivity of the proposed technique, the ultradian mechanical oscillation of the entire yeast culture is observed. This preliminary micro-rheological monitoring study makes possible the online optimization of bioethanol production.