"

From 2012.igem.org

Contents 1 French press user manual 1.1 Preparation of the French press 1.2 Operating of the French press 1.3 shutting off the French press

French press user manual

The French press is a mechanical cell disruption method by passing cells through a narrow valve under high pressure. When the sample passes the valve, bacteria cells will experience shear forces causing cellular disruption.

Important: very expensive and dangerous machine. Do not use when you are not certain about how to operate it.

Preparation of the French press

1. The cylinders are stored in the large cold room opposite the centrifuge room (next to the beer). Clean all the parts with demineralized water before using them.
2. Use the large cylinder, if your volume is above 5 mL. There are 5 parts which only fit in one way. Assemble all the parts except for the closing cap. Make sure you tighten the handle properly, otherwise you will lose sample.
3. Turn the cylinder with the piston in it upside down (piston down) in the rusty holder. Estimate the volume needed and adjust the piston. Moving the piston down is somewhat easier, so make a small estimate. Place the sample in the piston and put the cap on. Try to avoid any air bubbles inside of the cylinder by adjusting the piston.

Operating of the French press

1. Take the cylinder (do not push the piston in!) and place it with the piston upwards in the press. Close the bar on top of the cylinder.
2. Make sure the pressure increase is totally closed (turn to the left).
3. Put the left handle (black) on ‘high’ and turn on the press, slightly increase the pressure.
4. The cylinder will go up slowly until the piston is pushed into the cylinder.
5. Increase the pressure up to 1000 (never higher!).
6. Hold a 50 mL Greiner tube under the tube coming out of the cylinder.
7. Open the valve by turning the handle on the cylinder to the left.
8. Do not increase the pressure, but control the pressure by slowly opening the valve on the cylinder.
9. Wait until the cylinder is empty.

shutting off the French press

1. Put the handle to “down” and close the pressure increase. Take out the cylinder and turn off the French press.
2. Clean the five cylinder parts and put it back in the cold room. Clean also around the French Press.