Long-term Storage of Bacterial Strains

Materials and Equipment

1.Permanent marker

2.Fresh liquid bacterial culture; for most bacteria, a culture grown overnight, or for approximately 8–12 hours, works best for freezing

3.Micropipette (P1000) (1) and sterile tips (2)

4.Sterile microcentrifuge or screw-cap tube (1)

5.Sterile glycerol (autoclave to sterilize)

6.Liquid nitrogen (optional)

7.Resealable plastic bag

8.Freezer

Procedure

1.Using a permanent marker, label a sterile microcentrifuge or screw-cap tube with the date and the name of the bacteria.

2.Using a micropipette, add 150 µl of sterile glycerol to the tube.

3.With a new tip, use the micropipette to transfer 850 µl of the bacterial culture to the same tube.

4.Cap the tube and invert it several times to thoroughly mix the glycerol and bacteria.

5.If you are going to store the bacteria in a special -80°C freezer, you should first snap-freeze the bacterial stock by dropping it in a container of liquid nitrogen. If you are storing the bacteria in a regular -20°C freezer, the bacterial stock can be placed there with no further treatment.

Thanks very much i will try this method

Its k. All the best.......