The release of virus‐like particles from recombinant Saccharomyces cerevisiae : Effect of freezing and thawing on homogenization and bead milling

Recombinant cells of Saccharomyces cerevisiae , expressing virus‐like particles (Ty‐VLPs), can be readily disrupted in a high pressure homogenizer and show identical disruption kinetics to the untransformed host strain. When the cells are freeze/thawed before disruption, they become about four times more resistant to homogenization. This effect increases with the number of freeze/thaw cycles, but is independent of the time the cells remain frozen. The freeze/thaw effect is observed with cells harvested during both the logarithmic and stationary phase of growth, and occurs with the untransformed host strain as well as the transformed one. Freeze/thawed cells are twice as resistant to disruption in the bead mill as fresh cells. © 1994 John Wiley & Sons, Inc.