Large-scale disintegration of microorganisms by freeze-pressing

A semicontinuous press has been constructed for the disintegration of microorganisms and other biological material by freeze-pressing, i.e., pressure extrusion of frozen material through a narrow hole. The material to be freeze-pressed is frozen in the form of cylindrical rods, which fit into the pressure chamber and are extruded by a piston forced back and forth by means of a hydraulic pump. At a sample temperature of -35 degrees C and a press temperature of -20 degrees C, about 90% disruption is achieved in a single passage of undiluted baker's yeast (Saccharomyces cerevisiae, 270 mg/g) through the orifice of the pressure chamber. With this press about 10 kg of material can be freeze-pressed per hour.