Abstract: To effect disintegration of cells of microorganisms such as yeast, bacteria, and fungi, a suspension of cells is presaturated with a compressed gas and then passed through one or more disintegration units containing a plate valve seat and valve member urged toward each other. The disintegration unit can be attached to a mechanical vibrator-shaker. At the inlet of said disintegration unit there are two thick-wall vessels, i.e. a mixing vessel to effect intermixing of the suspension and compressed gas and a homogenizing vessel to maintain the suspension under pressure. When the suspension is passed through a throttling slit formed between the valve seat and valve member, cell shells are intensively broken due to the internal pressure.