Modification of a French pressure cell to improve microbial cell disruption.

A procedure for modification of the valve stem of a 40 K French pressure cell is described. The modification should be done by a machinist and requires a metalworking lathe. After modification of the valve stem, a torlon 4203 plastic ball is used between the valve stem and valve seat to control the pressure within the cell. The torlon plastic ball is a key component needed to obtain the high pressures required for efficient disruption of microbial cells.