Picking a Colony for Liquid Culture

Why?

-          To ensure genetic uniformity and consistent results in cloning, plasmid preparation, protein expression, etc.

Materials:

-          LB agar plate with bacterial colonies

-          LB broth (in a sterile tube or flask)

-          Sterile inoculating loop

-          Incubator with shaker

Steps:

-          Label your culture tube or flask with sample info, date and Name.

-          Use a sterile disposable tip/toothpick).

-          Gently touch a single, well-isolated colony on the LB agar plate.

-          Dip the tip into 2 mL of sterile LB broth in a culture tube. Swirl briefly to mix.

-          Incubate at 37⁰C, shaking 230 rpm for 4 hours.

-          Add 3 ml LB Broth to the tube (final volume = 5ml).

-          Continue incubation at 37°C, 230 rpm for an additional 6–12 hours (overnight is fine).

-          You should observe a cloudy culture by the next day, which indicates bacterial growth.

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