Once you’ve prepared a liquid culture, you can put the bacteria into storage or proceed to isolate the plasmid DNA. Lysogeny broth (also known as “LB broth” and “LB liquid”) is a type of nutrient-rich fluid used to propagate bacteria rapidly. It can be purchased from a retailer that sells laboratory equipment and materials. [2] X Research source Incubating bacterial cultures is a highly technical process involving many different variables. For this reason, it’s best performed by a trained technician in a controlled laboratory setting.
Diluting the glycerol is necessary to prevent it from damaging the bacterial cells. Some scientists prefer to use a glycerol solution as low as 15-40% in order to avoid compromising the bacterial culture. However, a 50% mixture will provide maximum longevity in storage.
If possible, use a tube with a screw top rather than one with a snap top. Snap top tubes have been known to come open accidentally during mixing and prolonged storage.
Using disproportionate amounts of glycerol and liquid culture could affect the hardiness of the bacteria and reduce the amount of time it’s able to survive in cold storage. If you’re using a glycerol solution with a lower concentration, you’ll need to adjust the quantity of the bacterial culture accordingly. Consult the literature relating to the exact strain you’re storing for more information.
Keep your thumb pressed firmly against the lid of the microfuge tube while shaking to make sure it doesn’t come loose.
Be sure to also record any other information that may prove useful during analysis, such as the exact strain of the sample or its origin. Labeling your sample containers is an indispensable step in the collection process, as it enables you to keep track of their contents as they’re shuffled around in and out of storage. [8] X Research source
It’s critical that the temperature of the freezer remain fixed at −80 °C (−112 °F). If it’s set any warmer, the preserved bacteria may die.
Be careful not to let the bacteria scraping thaw. It may help to keep the stock tube on dry ice until you’ve completed your tests. Only pull your sample out of the freezer when absolutely necessary. Repeated thawing and refreezing will decrease its lifespan considerably.
