Buchner Press

Buchner Press (Buchner), a hydraulic or oil press, adapted for laboratory needs and allowing for obtaining pure cell sap from tissues, yeast cells, and even bacteria. The material to be pressed is usually first rubbed with infusorial earth into a semi-dry mass, wrapped in very dense canvas, and in this form placed in a steel cylinder provided with numerous small holes, closed at the top by a tightly fitting piston. The cylinder with the material is placed on the press platform, and the piston is pressed down (as far as can be done by hand) by turning the upper wheel. In this way, a pressure of up to 40 atm can already be achieved. When further turning becomes impossible, a hydraulic pump is used, the small piston of which is an extension of the horizontal screw rod with a handle, while the large piston carries the aforementioned platform. Thus, now the platform is pressed against the press piston, and the pressure

can gradually be increased to 300 atm. In this process, the cells are crushed against the particles of infusorial earth, the cell sap is squeezed out and flows out of the holes in the steel cylinder. By means of the Buchner Press, it was first possible to obtain yeast sap that did not contain living cells but was capable of causing fermentation. At present, there are devices, a kind of micro-presses, that allow using an ordinary Buchner Press to press very small amounts of material (the price of a Buchner Press is about 1,200 marks).