Micromanipulation measurement of the mechanical properties of baker's yeast cells

The mechanical properties of a sample of baker's yeast cells were measured by micromanipulation. The relationship between the force required to burst a single cell and its corresponding diameter was established. For stationar y phase cells, the compressive force required to burst a cell varied betwee n 55 and 175 mu N, with a mean value of 101 +/- 2 mu N. This is a substanti al force compared to that required to burst a single mammalian cell (1.5-4. 5 mu N), which presumably reflects the lack of a cell wall of the latter. F rom measurements on 120 cells, there was no significant dependence of burst ing force on yeast cell size. The micromanipulation method will be valuable for studying the dependence of mechanical properties of yeast cells on fer mentation conditions, and the consequential effects of their behaviour in p rocess disruption operations.